WO2010113647A1 - ボルナ病ウイルスを利用するベクター及びその利用 - Google Patents
ボルナ病ウイルスを利用するベクター及びその利用 Download PDFInfo
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Definitions
- the present invention relates to a viral vector, a recombinant virus and its use for introducing a foreign gene into a cell.
- a method using a viral vector As a means for transporting foreign genes to living organisms or cells, a method using a viral vector is known. So far, vectors using retroviruses, lentiviruses, adenoviruses, adeno-associated viruses, and Sendai viruses have been developed.
- gene therapy a gene introduction technique capable of introducing a gene only to a target cell is expected.
- gene therapy is considered to be effective in the treatment of nervous system diseases, so the development of a viral vector that can selectively introduce genes into nerve cells and that has high safety, stability, persistence, and gene transfer efficiency. Is desired.
- Borna's disease virus (hereinafter also referred to as BDV) is a virus belonging to the order of the mononegavirus having a non-segmented minus-strand, single-stranded RNA as a genome, and is said to be apt to infect nerve cells. Has characteristics. Furthermore, although BDV is a virus that replicates in the cell nucleus, its infection is non-cytotoxic and has a characteristic of persistent infection over a long period of time, and has a characteristic that the host range that can be infected is extremely wide (Non-Patent Documents 1 and 2) etc).
- GFP green fluorescent protein
- Patent Document 1 includes (a) cDNA of a recombinant virus in which any foreign gene is inserted into the translation region of G gene of cDNA encoding Borna disease virus genome, (b) cDNA encoding ribozyme, and (c) Disclosed is a viral vector comprising a promoter sequence, wherein (b) is located upstream and downstream of (a), and (a) and (b) are located downstream of (c).
- the present invention is safe because the range of infectable hosts is wide, the efficiency of exogenous gene introduction is high, the viral genome is not inserted into the host chromosome, and the exogenous genes can be expressed non-cytotoxically in the cell nucleus. It has good stability and persistence in cells, and can selectively introduce foreign genes into target cells (for example, cells of central nervous system such as cranial nervous system). Viral vectors that can efficiently produce recombinant viruses with low pathogenicity (high safety) because they do not spread to cells, recombinant viruses, methods for introducing foreign genes using the recombinant viruses, foreign gene introducing agents, etc. The purpose is to provide.
- RNA virus genome RNA virus genome
- a viral vector containing cDNA of a recombinant viral genome in which an exogenous gene was inserted at various sites of cDNA encoding BDV genome cDNA of BDV genomic RNA
- BDV The plasmid (group) expressing N gene, P gene and L gene) was introduced into a cell to produce a recombinant virus, and the resulting recombinant virus was infected into the cell.
- the P gene was translated in the BDV genome.
- a vector in which an exogenous gene is inserted into the G gene region has a low ability to produce a recombinant virus, and the infection of the recombinant virus produced from the vector into a cell is transient, so that the foreign The sex gene could not be expressed.
- the recombinant BDV vector in which a foreign gene was inserted into the 5 'end region of the genome had a low gene introduction efficiency.
- the present inventors have found that a recombinant BDV vector in which an exogenous gene is inserted into an untranslated region between the translated region of the P gene and the translated region of the M gene has a higher virus production ability than the existing recombinant BDV vector It has been found that the recombinant virus produced from the vector can express the target gene for a long period of time with high efficiency even in brain nervous system cells. Has been conceived that can be efficiently introduced into target cells.
- the present inventors also have a set in which an exogenous gene is inserted into an untranslated region between the P gene ORF and the M gene ORF of the BDV genome (an untranslated region that binds downstream of the P gene ORF).
- an exogenous gene is inserted into an untranslated region between the P gene ORF and the M gene ORF of the BDV genome (an untranslated region that binds downstream of the P gene ORF).
- a viral vector using the cDNA of the modified BDV genome it was found that the pathogenicity of the recombinant virus produced from the vector can be reduced by destroying (deleting) the sequence encoding the G gene.
- Recombinant virus produced from such a G gene-deficient virus vector maintains its ability to replicate in the cell, so that it continuously infects the introduced cell, but cannot synthesize the G protein and thus other cells.
- the propagation ability of the recombinant virus can be further reduced while maintaining the replication ability in the cells. Further, in the viral vector, by deleting the intron of L gene (part of G gene) and binding the ORF of L gene which is divided by G gene in BDV genome, replication of recombinant virus produced It has been found that the ability can be improved, that is, the replication rate of the foreign gene in the cell can be increased.
- the present inventors further change the cell directivity of a recombinant virus by producing a recombinant virus using a gene encoding an outer shell protein of another virus together with the above-described viral vector in which the G gene is disrupted. Therefore, it was found that the target gene can be efficiently introduced into various cells.
- the BDV genome includes at least six proteins, namely, nuclear protein (N protein), X protein, phosphorylated protein (P protein), matrix protein (M protein), surface glycoprotein (G protein) and RNA-dependent RNA. Polymerase (L protein) is encoded.
- FIG. 1 is a diagram schematically showing the structure of a BDV genome.
- N, X, P, M, G, and L schematically show the ORF of each gene.
- the BDV genome has N, X, P, M, G, and L genes in this order from the 3 'end.
- G gene cDNA means a cDNA encoding the G gene.
- the present invention relates to the following items 1 to 14.
- Item 1 In the untranslated region having at least the N gene, X gene, P gene and L gene in the Borna disease virus genome in the same order as in the Borna disease virus genome and linked downstream of the translated region of the P gene A recombinant viral RNA cDNA having a sequence inserted with a foreign gene, (b) a DNA encoding a ribozyme, and (c) a promoter sequence, wherein (b) is arranged upstream and downstream of (a). And (a) and (b) are arranged downstream of (c).
- the cDNA of the recombinant viral RNA has a sequence in which the G gene is disrupted in the Borna disease virus genome, and a foreign gene has been inserted into the untranslated region linked downstream of the translated region of the P gene.
- the viral vector according to Item 1 which is cDNA of a recombinant viral RNA having a sequence.
- Item 3. The cDNA of the recombinant viral RNA has a sequence in which the G gene and M gene are disrupted in the Borna disease virus genome, and a foreign gene is present in the untranslated region linked downstream of the translated region of the P gene.
- the viral vector according to Item 1 or 2 which is a cDNA of a recombinant viral RNA having an inserted sequence.
- Item 4. (A) cDNA of a recombinant virus in which a foreign virus is inserted into an untranslated region between the P gene translation region and the M gene translation region of the cDNA encoding the Borna disease virus genome Item 5.
- (A) cDNA encoding (b1) hammerhead ribozyme is arranged upstream of cDNA of recombinant viral RNA, and (b2) cDNA sequence encoding hepatitis delta virus ribozyme is arranged downstream of (a) Item 6.
- the viral vector according to any one of Items 1 to 5, wherein
- Item 7. A recombinant virus comprising RNA encoded by the viral vector according to any one of Items 1 to 6.
- Item 8. A step of introducing a plasmid or a group of plasmids expressing the N gene, P gene and L gene of Borna disease virus as a helper plasmid together with the viral vector according to any one of Items 1 to 6 into the cell in vitro, and the viral vector; And a method for producing a recombinant virus, comprising a step of culturing cells into which a helper plasmid has been introduced to produce a recombinant virus.
- Item 9. Item 9.
- Item 10. The method for producing a recombinant virus according to Item 8 or 9, wherein a plasmid expressing the Borna disease virus M gene is further introduced into cells in vitro as a helper plasmid.
- Item 11 A method for introducing an exogenous gene, comprising a step of infecting a cell or an animal with the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10.
- Item 12. An exogenous gene introduction agent comprising the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10.
- Item 13 An agent for introducing an exogenous gene into a brain nervous system cell, comprising the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10.
- Item 14 An exogenous gene introduction kit comprising the viral vector according to any one of Items 1 to 6.
- the present invention also includes the following methods, uses and the like.
- a method for introducing an exogenous gene into a brain nervous system cell wherein the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10 is administered to an animal; Use of the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10 for producing an exogenous gene introduction agent.
- Item 11 Use of the recombinant virus according to Item 7 or the recombinant virus produced by the method according to any one of Items 8 to 10 for producing an exogenous gene introduction agent into brain nervous system cells.
- Item 11 A recombinant virus according to Item 7 or a recombinant virus produced by the method according to any one of Items 8 to 10 for introducing a foreign gene into a cerebral nervous system cell.
- the infectious host range is wide, the efficiency of exogenous gene introduction is high, the viral genome is not inserted into the host chromosome, it is safe, and the exogenous gene can be expressed non-cytotoxically in the cell nucleus. Therefore, the stability and persistence in the host cell is good, and the foreign gene can be selectively introduced into the target cell such as a cell of the cranial nervous system and is not transmitted to cells other than the target cell. Therefore, a virus vector and a recombinant virus that can produce a recombinant virus with low pathogenicity (high safety) with high productivity can be produced.
- a foreign gene can be selectively and efficiently introduced into a target cell such as a cranial nervous system cell, and the foreign gene can be continuously expressed in the cell.
- the recombinant virus produced from the viral vector of the present invention causes persistent infection in the nucleus of cells such as cranial nervous system cells, it is difficult to be attacked by host immunity and difficult to eliminate.
- the P protein possessed by the recombinant virus of the present invention has a function of inhibiting the host immunity response pathway, and activation of innate immunity does not occur in virus-infected cells.
- FIG. 1 is a diagram schematically showing the structure of the genome (wild type) of Borna disease virus.
- FIG. 2 (a) schematically shows an untranslated region (1875 to 1895 as base numbers of the BDV genome) between the ORF of the P gene and the ORF of the M gene in the cDNA of the wild-type BDV genome.
- B is a diagram schematically showing an example of a foreign gene insertion site in the virus vector of the present invention.
- FIG. 3 is a diagram schematically showing an example of the structure of the viral vector of the present invention.
- FIG. 4 is a diagram schematically showing the structure of a recombinant viral vector (rBDV-5′GFP) in which a GFP gene is inserted into the untranslated region on the 5 ′ end side of the BDV genome.
- FIG. 5 is a graph showing changes over time in Vero cells infected with wild-type or recombinant BDV (change in infection rate from 0 to 19 days after infection).
- FIGS. 6 (a) and 6 (b) show the results of examining the gene expression in cells infected with wild-type BDV, recombinant virus p / mGFP and recombinant virus 5′GFP by Northern blotting (a), And (b) shows the results of examining protein expression by Western blotting.
- FIGS. 7a to f are photomicrographs showing the results of examining protein expression in cells infected with wild type BDV, recombinant virus p / mGFP and recombinant virus 5'GFP, respectively.
- FIGS. 8a to 8f are photomicrographs showing the results of examining protein expression in cells infected with wild-type BDV, recombinant virus p / mGFP, and recombinant virus 5'GFP, respectively.
- FIG. 9 is a diagram for explaining an experimental method for examining viral infection in the rat brain.
- FIG. 10 is a diagram showing the site of inoculation of virus into the rat brain.
- FIGS. 12a to 12d are a macro photograph (a and b) in which a rat brain is dissected 14 days after inoculation of the recombinant virus and turned over, and a macro fluorescence photograph (c and d) of the brain.
- 13A and 13B are a macrophotograph (upper figure) of a cerebral cortex of a rat brain infected with a virus and a micrograph (ad) of a section of the cerebral cortex, respectively.
- FIGS. 12a to 12d are a macrophotograph (upper figure) of a cerebral cortex of a rat brain infected with a virus and a micrograph (ad) of a section of the cerebral cortex, respectively.
- FIGS. 15 (a) and 15 (b) are photomicrographs showing the results of examining protein expression in cells infected with the recombinant virus obtained from the rBDV-p / mDsRed vector.
- FIGS. 15 (a) and 15 (b) are micrographs (a) and luciferase activities (FIG. 15) showing the results of examining protein expression in cells infected with the recombinant virus obtained from the rBDV-p / mLuci vector, respectively. It is a figure which shows b).
- FIG. 16 is a diagram schematically showing an example of the structure of the viral vector of the present invention.
- FIG. 17 is a diagram schematically showing an example of the structure of the virus vector of the present invention.
- FIG. 16 is a diagram schematically showing an example of the structure of the viral vector of the present invention.
- FIG. 18 is a fluorescence micrograph (FIG. 18a: macro photo, FIG. 18b: 400 ⁇ enlarged photo of FIG. 18a) of the brain cut surface of the mouse 8 months after inoculation with the recombinant virus.
- FIG. 19 is a diagram showing an outline of the preparation procedure of plasmid p / mGFP ⁇ G.
- FIG. 20 is a diagram showing an outline of the preparation procedure of plasmid p / mGFP ⁇ G LL.
- FIG. 21 is a diagram showing an outline of a procedure for preparing a BDV G gene expression plasmid.
- FIG. 22 is a diagram comparing the recombinant BDV production ability of plasmids p / mGFP ⁇ G and p / mGFP / ⁇ G LL, respectively.
- FIG. 23 is a graph showing the transition of the infection rate of p / mGFP ⁇ G-LL virus to Gero stably expressing Vero cells and Vero cells.
- FIG. 24a is a diagram showing the results of examining protein expression in cells infected with wild-type BDV and G-deficient recombinant virus by Western blotting, and FIG. 24b shows infection with G-deficient recombinant virus.
- FIG. 3 is a fluorescence micrograph of Vero cells expressing GFP.
- FIG. 25 is a diagram showing an outline of a procedure for preparing a chimeric protein expression plasmid having a BDV G gene intracellular region and vesicular stomatitis virus (VSV) G gene extracellular and transmembrane regions.
- FIG. 26 is a diagram showing the recovery efficiency of G-deficient recombinant viruses when using the BDV G gene or any of the outer genes of VSV and rabies virus (Rab) as a helper plasmid.
- FIG. 27 is a diagram showing an outline of a procedure for preparing a plasmid p / mGFP ⁇ M-G LL in which the M gene is deleted.
- FIG. 28 is a diagram showing an outline of the production procedure of p / mGFP ⁇ M-G LL P-M tandem vector.
- FIG. 29 shows the results of Western blotting of recombinant virus p / mNEP-infected cells.
- FIG. 30 is a diagram showing the enzyme activity of NEP in cells infected with a recombinant virus.
- FIG. 31 is a diagram showing an outline of a procedure for preparing a p / m miR155 introduction vector (pSIRIUS-B).
- FIG. 32 is a diagram showing an outline of the procedure for preparing plasmid p / m miR155.
- FIG. 33 is a diagram showing the transcription inhibition efficiency of a target gene in a cell infected with a recombinant virus.
- FIG. 34 is a diagram showing an outline of the procedure for preparing plasmid p / m miRx2.
- FIG. 35 is a schematic diagram of a p / m vector into which miRNA ⁇ 1 (p / m miR155), miRNA ⁇ 2, and miRNA ⁇ 4 are inserted.
- FIG. 36 is a diagram showing the effect of infection with a recombinant virus p / m-miR-GAPDH having a recombinant viral RNA inserted with miRNA against GAPDH.
- FIG. 37 is a diagram showing the effect of infecting a recombinant virus p / m-miR-APP having a recombinant virus RNA into which miRNA for APP (amyloid precursor protein) is inserted.
- the viral vector of the present invention has (a) at least N gene, X gene, P gene and L gene in the Borna disease virus genome in the same order as in the Borna disease virus genome, and the translation region of the P gene
- a recombinant viral RNA cDNA having a sequence in which an exogenous gene is inserted in an untranslated region linked downstream thereof, (b) a DNA encoding a ribozyme, and (c) a promoter sequence, upstream of the (a) And (b) is arranged downstream, and (a) and (b) are arranged downstream of (c).
- the cDNA of the recombinant viral RNA of (a) is also simply referred to as “(a) cDNA of recombinant BDV genome”.
- the viral vector of the present invention may contain sequences other than the above (a), (b) and (c) as long as the effects of the present invention are exhibited.
- the cDNA of (a) recombinant BDV genome in the present invention is a cDNA of recombinant BDV RNA having at least N gene, X gene, P gene and L gene in the BDV genome in the same order as in the Borna disease virus genome.
- the recombinant BDV RNA has a sequence in which an exogenous gene is inserted into an untranslated region linked downstream of the translated region of the P gene.
- a cDNA of such (a) recombinant BDV genome in the BDV genome or a sequence in which either or both of the G gene and M gene are disrupted in the BDV genome, an untranslated region linked downstream of the translated region of the P gene
- a cDNA encoding a sequence having a foreign gene inserted therein is preferably used.
- (a) as a cDNA of the recombinant BDV genome in the present invention a sequence in which either or both of the G gene and the M gene are disrupted in the BDV genome, and non-translation linked to the downstream of the translation region of the P gene
- An RNA cDNA having a sequence in which a foreign gene is inserted in the region is preferred.
- the cDNA of (a) recombinant BDV genome more preferably has a sequence in which the G gene is disrupted in the BDV genome and is exogenous in the untranslated region linked downstream of the translated region of the P gene. It is cDNA of a recombinant viral RNA having a sequence into which a gene has been inserted.
- a virus vector containing a cDNA of a recombinant viral RNA having a sequence in which the G gene is disrupted as cDNA of the recombinant BDV genome is hereinafter also referred to as “G gene-deficient virus vector”.
- the recombinant virus produced from the viral vector does not propagate to cells other than the introduced cells, so that pathogenicity is reduced and safety is high. More preferably, a recombinant virus having a sequence in which the G gene and M gene are disrupted in the BDV genome, and a sequence in which a foreign gene is inserted in an untranslated region linked downstream of the translated region of the P gene.
- RNA cDNA Such a viral vector containing the cDNA of the recombinant viral RNA is hereinafter also referred to as “G gene and M gene deficient viral vector”.
- Disrupting a gene usually means that the gene does not exist in a form capable of encoding a protein (for example, G protein in the case of G gene).
- the gene can be destroyed by deleting a part of the gene, inserting another sequence into the gene, or replacing an amino acid in the gene with another amino acid. it can.
- the intron of the L gene in the BDV genome is deleted.
- the ORF of the L gene that is fragmented in the natural BDV genome is linked as shown in FIG. 16, so that the replication ability of the recombinant virus, that is, the foreign gene in the cell Expression efficiency is further improved.
- the intron of the L gene is deleted, a larger foreign gene can be inserted.
- the intron of the L gene can be removed by a known method.
- a recombinant BDV genome cDNA a recombinant virus in which a foreign gene is inserted into an untranslated region between the P gene translation region and the M gene translation region of the cDNA encoding the BDV genome.
- cDNA can also be used.
- Such a recombinant BDV genome cDNA is a cDNA encoding a BDV genome (RNA virus genome), and is arbitrarily located in an untranslated region between the translation region (ORF) of the P gene of BDV and the translation region of the M gene. A foreign gene has been inserted.
- FIG. 3 schematically shows an example of the cDNA structure of (a) the recombinant BDV genome in the virus vector of the present invention.
- FIG. 3 is a cDNA of a recombinant virus in which a foreign gene is inserted into an untranslated region between the translated region of the P gene and the translated region of the M gene of cDNA encoding the BDV genome.
- FIG. 16 schematically shows an example of a preferable structure of (a) cDNA of recombinant BDV genome in the virus vector of the present invention.
- the cDNA of the recombinant BDV genome shown in FIG. 16 has a sequence in which the G gene is disrupted (deleted) in the BDV genome, and an exogenous gene is present in the untranslated region linked downstream of the translated region of the P gene.
- Recombinant viral RNA cDNA with an inserted sequence is provided.
- FIG. 17 schematically shows an example of another preferred structure of (a) cDNA of recombinant BDV genome in the virus vector of the present invention.
- the cDNA of the recombinant BDV genome shown in FIG. 17 has a sequence in which the G gene and M gene are destroyed (deleted) in the BDV genome, and is foreign in the untranslated region linked downstream of the translated region of the P gene.
- It is a cDNA of a recombinant viral RNA having a sequence into which a sex gene has been inserted.
- M surrounded by a dotted line in FIG. 17 indicates the deleted M gene.
- the L gene is divided by the G gene.
- the L gene in the BDV genome is deleted by partially deleting the G gene. Since the intron is deleted, the ORF of the L gene is linked at the part indicated by the arrow in the figure.
- the BDV genome in the present invention may be a gene belonging to a virus belonging to Bornaviridae (Bornaviridae) or a mutant strain thereof.
- viruses belonging to the Bornaviridae include strains such as He80, H1766, Strain V, and huP2br.
- mutant strain include No / 98, Bo / 04w, HOT6, and the like.
- the BDV genome retains its function as a BDV
- a part of these genome sequences may be substituted with other bases, deleted, or newly inserted, and further, one of the base sequences.
- the part may be rearranged. Any of these derivatives can be used in the present invention.
- the part may be, for example, 1 to several (usually 1 to 5, preferably 1 to 3, more preferably 1 to 2) in terms of amino acid residues.
- BDV genome and cDNA of RNA having a sequence in which G gene or the like is disrupted in BDV genome can be prepared based on the virus genome information.
- cDNA can be prepared from an RNA genome using a sequence reversal enzyme.
- RNA cDNA having a sequence in which the G gene is disrupted in the BDV genome can be easily prepared, for example, by performing PCR using the BDV genome cDNA as a template and using appropriate primers.
- RNA cDNA having a sequence in which the G gene and the M gene are disrupted in the BDV genome is, for example, a BDV genome cDNA or an RNA cDNA having a sequence in which the G gene is disrupted in the genome as a template and an appropriate primer. And can be easily prepared by performing PCR. Further, it can be chemically synthesized using a DNA synthesizer based on the sequence of the RNA genome or a sequence obtained by deleting the G gene from the RNA genome. Alternatively, as a method for obtaining cDNA of (a) recombinant BDV genome in the present invention, a method using a known amplification means such as PCR can be mentioned. Operations such as PCR and primer preparation can be performed by a known genetic engineering technique (gene manipulation technique).
- the cDNA of the recombinant BDV genome is a cDNA of a recombinant viral RNA having a sequence in which an arbitrary foreign gene is inserted in the untranslated region linked downstream of the ORF of the P gene in the BDV genome.
- the untranslated region linked downstream of the ORF of the P gene is an untranslated region between the translated region of the P gene and the translated region of the M gene (hereinafter simply referred to as “P gene and M gene”). It is also referred to as “the non-translated region between”.
- the recombinant virus productivity of the viral vector that is, the replication efficiency of the recombinant virus produced from the viral vector can be increased.
- Recombinant virus can be produced.
- a recombinant virus produced (replicated) from the viral vector can efficiently express a foreign gene when introduced into a cell. Therefore, when the viral vector of the present invention is introduced into a cell, or when a cell is infected with a recombinant BDV produced from the viral vector, any foreign gene is efficiently introduced into the cell. That is, the foreign gene is efficiently expressed in the cell. As shown in FIG.
- the BDV genome base numbers 1875 to 1895 ie, bases 1875 to 1895 of SEQ ID NO: 1
- Base numbers 1875 to 1882 and the start signal sequence of the M gene (base numbers 1875 to 1890 of SEQ ID NO: 1).
- the insertion site of the foreign gene in the untranslated region between the translated region of the P gene and the translated region of the M gene is a P gene stop signal.
- a region that does not include the sequence and / or the start signal sequence of the M gene is preferable, and a region that does not include the stop signal sequence of the P gene and the start signal sequence of the M gene is more preferable.
- the base number of SEQ ID NO: 1 is particularly preferably between 1890 and 1891.
- the recombinant BDV genome in the present invention can contain restriction enzyme sites on both sides or one side (preferably on both sides) of the foreign gene. It is preferable to have a restriction enzyme site, since the foreign gene can be easily incorporated into the BDV genome sequence and the translation efficiency of the foreign gene into the protein is increased.
- the restriction enzyme sites that can be arranged on both sides or one side of the foreign gene include, for example, the Bst'BI site, Pac I site, Sse8387 I site, and Swa I for the 3 ′ end side of the foreign gene. Site, Kpn I site, etc., and Bst BI site is preferred. Examples of the 5 ′ terminal side of the foreign gene include Pac I site, Bst BI site, Sse8387 I site, Swa I site, Kpn I site and the like, and Pac I site is preferable.
- the cDNA of the recombinant BDV genome in the present invention contains an M gene
- the cDNA of the recombinant BDV genome includes a foreign gene (and restriction enzyme sites arranged on both sides or one side as required) and P. Between the gene ORF and between the exogenous gene (and restriction enzyme sites located on either side or one side as required) and the M gene ORF, respectively, It is preferred that there is a sequence containing the start signal sequence (taaaaaatcgaatca (SEQ ID NO: 11)).
- SEQ ID NO: 11 the start signal sequence taaaaaatcgaatca
- FIG. 2 (b) shows a recombinant BDV genome cDNA containing the M gene as an example.
- a sequence comprising a P gene stop signal sequence and an M gene start signal sequence (SEQ ID NO: 11) downstream of the foreign gene. It is preferable to have.
- the stop signal sequence of the P gene and the start signal sequence of the M gene shown in FIG. 2B are the stop signal of the foreign gene and the start of the L gene. Acts as a signal.
- FIG. 2 (b) shows an example in which a Bst BI site is inserted at the 3 ′ end side of the foreign gene and a Pac I site is inserted at the 5 ′ end side of the foreign gene.
- the restriction enzyme sites arranged on both sides are not limited to these.
- the type and length of the exogenous gene in the present invention are not particularly limited, and a desired gene can be used according to the purpose.
- a desired gene can be used according to the purpose.
- cDNA of a gene encoding a protein or peptide siRNA, cDNA encoding short hairpin RNA (shRNA), microRNA DNA (miRNA), cDNA encoding RNA aptamer, or the like can be used.
- shRNA short hairpin RNA
- miRNA microRNA DNA
- the ribozyme may be any sequence that can cleave any foreign gene transcribed from the cDNA of the recombinant virus (a).
- Examples of (b) include DNA such as cDNA encoding ribozymes such as hammerhead ribozyme (HamRz), hepatitis delta virus ribozyme (HDVRz), hairpin ribozyme, artificial ribozyme and the like.
- DNA such as cDNA which codes the modified ribozyme of the said ribozyme, can also be used.
- the modified ribozyme has a common sequence and 1 to several bases (for example, several are, for example, 10, preferably 5, more preferably 3, more preferably 2). And a polynucleotide comprising a deleted or added base sequence and functioning as a ribozyme.
- a DNA encoding hamRz (preferably cDNA) is located upstream of the cDNA of the recombinant BDV genome, ie, at the 3 ′ end, and downstream of the (a), ie, 5 ′ end.
- a DNA (preferably cDNA) sequence encoding HDVRz is arranged on the side. Thereby, the expression efficiency of the foreign gene in the cell is improved.
- the base sequence of HamRz is described in Yanai et al., Microbes and Infections 8 (2006) 1522-1529, Mercier et al., J. Virol. 76 (2002) 2024-2027 and Inoue et al., J. Virol. Methods 107 (2003) 229-236.
- the base sequence of HDVRz is Ferre-D'Amare, AR, Zhou, K. and Doudna, JA Crystal structure of a hepatitis delta virus ribozyme. Nature 395 (6702), 567-574 (1998) Etc. are described.
- cDNA encoding the base sequence of HamRz described in these documents can be used.
- HamRz 5'-UUGUAGCCGUCUGAUGAGUCCGUGAGGACGAAACUAUAGGAAAGGAAUUCCUAUAGUCAGCGCUACAACAAA-3 '(SEQ ID NO: 2)
- HDVRz 5'-GGCCGGCAUGGUCCCAGCCUCCUCGCUGGCGCCGGCUGGGCAACACCAUUGCACUCCGGUGGCGAAUGGGAC-3 ' (SEQ ID NO: 3)
- RNA polymerase II promoter sequences examples include RNA polymerase II promoter sequences, RNA polymerase I promoter sequences, and T7 polymerase promoter sequences. Among them, RNA polymerase II promoter sequences are included. preferable. Examples of the RNA polymerase II promoter include CMV promoter and CAGGS promoter. Among these, CAGGS promoter is particularly preferable. Such a promoter sequence is, for example, JA Sawicki, RJ Morris, B. Monks, K. Sakai, J. Miyazaki, A composite CMV-IE enhancer / b-actin promoter is ubiquitously expressed in mouse cutaneous epithelium, Exp. 244 (1998) 367-369.
- a cDNA encoding a hammerhead ribozyme is disposed upstream of (a) a recombinant viral RNA cDNA (cDNA of a recombinant BDV genome), and downstream of the (a) (B2) a cDNA sequence encoding hepatitis ⁇ virus ribozyme is arranged. Further, (a) and (b) are arranged downstream of the promoter of (c) RNA polymerase II system.
- the viral vector of the present invention can contain a partial or entire sequence of the SV40 viral replication origin / promoter region sequence. Further, when the viral vector contains a part or all of the SV40 viral replication origin / promoter region sequence, the sequence is preferably arranged downstream of (a) and (b). As a part of the SV40 viral DNA replication origin / promoter region sequence, a fragment consisting of 113 bases on the 5 ′ side in the SV40 replication origin / promoter region is suitable.
- SV40 virus replication origin / promoter region sequence (SEQ ID NO: 4) is, for example, DA Dean, BS Dean, S. Muller, LC Smith, Sequence requirements for plasmid nuclear import, Exp. Cell. Res. 253 (1999) 713- 722 etc.
- the viral vector of the present invention further encodes one or more factors advantageous for protein expression, such as an enhancer, an activator (for example, a trans-acting factor), a chaperone, and a processing protease, as long as the effects of the present invention are exhibited.
- factors advantageous for protein expression such as an enhancer, an activator (for example, a trans-acting factor), a chaperone, and a processing protease, as long as the effects of the present invention are exhibited.
- multiple nucleic acid sequences can also be included.
- the viral vector of the present invention may have any factor that is functional in the selected cell.
- the viral vector of the present invention may be linear DNA or circular DNA, but is preferably circular when introduced into a cell.
- the circular virus vector include the DNAs (a), (b) and (c), which are essential sequences of the virus vector of the present invention, and the DNA (d) contained as necessary.
- Examples include those arranged in a commercially available plasmid vector in the above-described predetermined order.
- a commercially available plasmid vector may be any plasmid vector as long as it is capable of self-replication in a cell into which a viral vector is introduced. Examples thereof include pBluescript SKII ( ⁇ ), pCAGGS, pCXN2, and pCDNA3.1.
- the production method of the viral vector of the present invention is not particularly limited, and a known genetic engineering technique may be used.
- a known genetic engineering technique may be used.
- the CAT gene is replaced with the genomic sequence of BDV, and the P gene
- the self-replicating (persistent infection type) virus vector of the present invention is inserted by inserting a target foreign gene into a non-translated region (non-translated region between P gene and M gene) linked downstream. Can be produced.
- the viral vector prepared by the above method comprises: (a) a recombinant viral RNA cDNA that is a foreign gene in the untranslated region between the P gene translation region and the M gene translation region of the cDNA encoding the BDV genome. And a recombinant virus cDNA (for example, a recombinant virus cDNA having a structure schematically shown in FIG. 3).
- the G gene-deficient virus vector and the G gene and M gene-deficient virus vector can be obtained by using, for example, (a) a cDNA encoding a BDV genome as a cDNA of a recombinant virus RNA.
- CDNA of a recombinant virus in which a foreign gene is inserted into a non-translation region between the translation region of the P gene and the translation region of the M gene for example, (a) a recombinant virus RNA having the structure schematically shown in FIG.
- the G gene-deficient virus vector in the present invention can be prepared by inserting a deletion mutation or the like into the G gene by PCR or the like using the self-replicating virus vector having (cDNA) as a template.
- the intron portion of the L gene is similarly scraped by PCR to produce a more preferred G gene-deficient virus vector in the present invention.
- the G gene and M gene deficient virus vectors can be prepared by deleting the M gene by PCR or the like using the G gene deficient virus vector as a template.
- the circular viral vector is used in the region other than (a) the cDNA region of the recombinant BDV genome, (c) the promoter sequence region, and other signal sequence regions necessary for protein expression.
- a linear viral vector can be prepared by appropriately selecting a restriction enzyme that cleaves at one site according to the type of the vector and cleaving the circular viral vector with the restriction enzyme.
- a method for introducing the foreign gene contained in the viral vector of the present invention into the target cell a method for introducing the viral vector into the target cell together with a helper plasmid described later, a recombinant virus produced from the viral vector is used as the target cell.
- a method using a recombinant virus produced from a viral vector is preferred.
- the recombinant virus produced from the viral vector of the present invention is a recombinant BDV having RNA encoded by the viral vector in place of the wild-type BDV genome.
- Recombinant virus A recombinant virus containing RNA encoded by the above-described viral vector is also one aspect of the present invention.
- it is a recombinant virus containing RNA encoded by a viral vector, and N protein of BDV, P protein of BDV and L protein of BDV.
- the recombinant virus of the present invention is a persistently-infected recombinant virus that contains the above-mentioned recombinant BDV genome and can continuously express a foreign gene after infection of cells.
- the recombinant virus may optionally have a BDV G protein or an outer shell protein of another virus, and may further have a BDV M protein.
- the outer shell gene in the present invention is a gene encoding a viral outer shell protein. In BDV, the gene encoding the outer shell protein is the G gene.
- the recombinant virus of the present invention includes, for example, a step of introducing a plasmid or a group of plasmids expressing the N gene, P gene and L gene of BDV as a helper plasmid together with the above virus vector into an in vitro cell, and the virus vector and It can be prepared by a method comprising a step of culturing cells into which a helper plasmid has been introduced to produce a recombinant virus.
- a method for producing a recombinant virus is also one aspect of the present invention.
- a recombinant virus can be produced in vitro.
- In vitro cells into which viral vectors and helper plasmids are introduced are usually cultured cells.
- a G gene-deficient virus vector when used, it is preferable to introduce a plasmid that expresses the outer gene of the virus into an in vitro cell as a helper plasmid.
- the outer gene of the virus may be appropriately selected according to the target cell into which the foreign gene is introduced, and the outer gene of a virus other than BDV G gene or BDV can be used.
- the G gene and M gene deficient virus vectors when used, it is preferable to introduce a plasmid expressing the M gene of BDV virus into the cells as a helper plasmid.
- the plasmid or plasmid group expressing the N gene, P gene and L gene of the BDV, and the plasmid expressing the outer gene of the virus and the M of the BDV virus. It is preferable to introduce a plasmid expressing the gene into cells in vitro.
- the helper plasmid may be any one that can express the N gene, the P gene, the L gene and the M gene of BDV, and the outer gene of the virus, and two or more of these genes are included in one plasmid. These genes may be contained in different plasmids. For example, as a plasmid for expressing the N gene, P gene, and L gene of BDV, any one of the following plasmids (1) to (4) or a plasmid group is preferably used.
- a plasmid expressing the N gene of BDV, a plasmid expressing the P gene of BDV, and a plasmid expressing the L gene of BDV (2) A plasmid expressing the N and P genes of BDV, and the L gene of BDV Plasmid to be expressed (3) Plasmid to express BDV N gene and L gene, and plasmid to express BDV P gene (4) Plasmid to express BDV N gene, L gene and P gene
- a helper plasmid provides a viral protein necessary for BDV genome replication, and an infectious recombinant virus can be produced by introducing a helper plasmid into a cell together with a viral vector.
- the plasmid (group) of any one of (1) to (4) that expresses the BDV N gene, P gene and L gene in a helper plasmid the plasmid group of any one of (1) to (3) is preferable.
- the virus vector used in the method for producing the recombinant virus of the present invention and the preferred embodiment thereof are the same as described above.
- the helper plasmid in the present invention is not limited as long as it can express the N gene, the P gene, and the L gene of BDV in the cell when introduced into the cell together with the virus vector.
- the plasmid expressing the BDV N gene is preferably a plasmid in which the BDV N gene cDNA is arranged downstream of the promoter sequence.
- a plasmid for expressing the BDV P gene a plasmid in which the BDV P gene cDNA is arranged downstream of the promoter sequence is preferable.
- a plasmid for expressing the BDV L gene a plasmid in which the BDV L gene cDNA is arranged downstream of the promoter sequence is preferably used.
- plasmid for expressing the BDV N gene and P gene a plasmid in which the BDV N gene cDNA and the P gene cDNA are arranged in this order downstream of the promoter sequence.
- a plasmid for expressing the BDV N gene and L gene a plasmid in which the BDV N gene cDNA and the P gene cDNA are arranged in this order downstream of the promoter sequence.
- a plasmid for expressing BDV N gene, L gene and P gene a plasmid in which BDV N gene cDNA, L gene cDNA and P gene cDNA are arranged in this order downstream of the promoter sequence.
- the helper plasmid is introduced into the cell together with the G gene-deficient viral vector, and the BDV N gene, P gene, L gene and virus in the cell. Any gene can be used as long as it can express the outer shell gene.
- the helper plasmid may be any one that can further express the BDV M gene in the cell.
- the plasmid that expresses the outer gene of the virus and the plasmid that expresses the M gene of BDV can be used together with any of the plasmids (groups) described in (1) to (4) above, for example. Furthermore, as a plasmid that expresses the outer shell gene, a plasmid that expresses one or more genes selected from the group consisting of the N gene, the L gene, and the P gene of BDV, and the outer shell gene of the virus can also be used. As the plasmid for expressing the outer shell gene, a plasmid in which the cDNA of the outer shell gene is arranged downstream of the promoter sequence is preferable.
- the outer shell protein encoded by the outer shell gene such as G gene of BDV is usually a transmembrane protein, and its amino acid sequence includes a region located outside the cell (extracellular sequence), a transmembrane region (transmembrane through the cell membrane). Sequence) and a region located within the cell (intracellular sequence).
- the outer shell gene in the helper plasmid may be the G gene of BDV.
- the envelope genes of all envelope viruses that use the host cell membrane as the outer shell such as vesicular stomatitis virus, rabies virus, measles virus, and retrovirus, are used.
- the intracellular sequence of the G protein of BDV is encoded as the intracellular sequence.
- the outer shell gene in the present invention has the intracellular sequence of the G protein of BDV as the intracellular sequence, and has the extracellular sequence and the transmembrane sequence of the outer shell protein of any virus (virus other than BDV or BDV).
- a gene encoding a protein is preferable.
- the intracellular sequence of the G protein of BDV as the intracellular sequence, the recombinant virus production efficiency is improved.
- the gene sequence encoding the intracellular sequence in the shell gene is converted into the intracellular sequence of the G protein of BDV by a known genetic engineering technique. It is preferable to use it by substituting it with a sequence encoding.
- the cell directivity of the produced virus can be changed depending on the type of virus from which the gene is derived. For example, when infecting epithelial cells, respiratory cells, etc. with a recombinant virus, viruses with high directivity to epithelial cells, respiratory cells, etc.
- helper plasmid that expresses an outer shell gene that encodes the extracellular sequence of the outer shell protein and the transmembrane sequence of the outer shell protein and the intracellular sequence of the G protein of BDV.
- a plasmid that expresses the M gene a plasmid that expresses one or more genes selected from the group consisting of the BDV N gene, L gene, P gene, and viral coat gene, and a BDV M gene may also be used. it can.
- a plasmid for expressing the M gene a plasmid in which the BDV M gene cDNA is arranged downstream of the promoter sequence is preferable.
- BDV N gene cDNA, P gene cDNA, and L gene cDNA can be prepared based on the sequence information of the BDV N gene, P gene, and L gene, respectively.
- the BDV M gene cDNA and G gene cDNA can be prepared based on the sequence information of the BDV M gene and G gene, respectively.
- cDNA can be prepared from RNA using sequence reversal enzymes. Further, it can be chemically synthesized using a DNA synthesizer based on the RNA sequence.
- BDV N gene, P gene and L gene, and M gene and G gene examples include Cubitt, B., Oldstone, C. and de la Torre, JC Sequence and genome organization of Borna disease virus. Virol. 68 (3), 1382-1396 (1994) can be used. Moreover, as these genes, RNA synthesized according to the above sequence can also be used. Furthermore, it is possible to obtain fragments by hybridization and PCR methods based on amino acid sequences conserved among BDV N, P, L, M and G proteins. Furthermore, it is possible to obtain fragments by degenerate RT-PCR using mix primers designed based on the sequences of other known N gene, P gene, L gene, M gene and G gene of BDV. .
- the base sequence of the obtained fragment can be determined by a usual method.
- the proteins encoded by the genes are BDV N protein, P protein and L protein, and M gene and G protein, respectively.
- a part of the base sequence may be substituted, deleted or newly inserted with another base, and a part of the base sequence may be rearranged. Any of these derivatives can be used in the present invention.
- the part may be, for example, 1 to several (1 to 5, preferably 1 to 3, more preferably 1 to 2) in terms of amino acid residues.
- an N gene for example, a polypeptide having a sequence identity of at least about 90%, preferably about 95% or more, more preferably about 98% or more with the BDV N gene and having the function of an N protein RNA encoding can also be used as the N gene of BDV in the present invention.
- An RNA encoding a polypeptide having a sequence identity of at least about 90%, preferably about 95% or more, more preferably about 98% or more with the P gene of BDV and having a function of P protein is also provided in the present invention. It can be used as the P gene of BDV in the invention.
- RNA encoding a polypeptide having a sequence identity of at least about 90%, preferably about 95% or more, more preferably about 98% or more with the L gene of BDV and having the function of L protein is also used in the present invention. It can be used as L gene of BDV.
- An RNA encoding a polypeptide having a sequence identity of at least about 90%, preferably about 95% or more, more preferably about 98% or more with the G gene of BDV and having the function of a G protein is also used in the present invention. It can be used as the G gene for BDV.
- RNA encoding a polypeptide having a sequence identity of at least about 90%, preferably about 95% or more, more preferably about 98% or more with the M gene of BDV and having the function of M protein is also used in the present invention. It can be used as the M gene for BDV. Sequence identity is determined by CLUSTAL W, GCG program, GENETYX, BLAST search.
- vesicular stomatitis virus is GeneBank, No: J02428.1
- rabies virus is GeneBank, No: AB044824.1.
- a sequence encoding an extracellular sequence and a transmembrane sequence of the outer shell protein in these outer shell genes is used.
- the sequence encoding the extracellular and transmembrane sequences of the outer shell protein in the outer shell gene is Garry RF. Proteomics computational analyses suggest that the bornavirus glycoprotein is a class III viral fusion protein ( ⁇ penetrene).
- RNA synthesized according to the above sequence can also be used.
- an RNA encoding a polypeptide having at least about 90%, preferably about 95% or more, more preferably about 98% or more sequence identity with such an outer shell gene and having the function of an outer shell protein. can also be used as a viral coat gene in the present invention.
- the circular helper plasmid is, for example, one or more factors that are advantageous for protein expression, such as an enhancer or activator in a form in which a promoter sequence, which is an essential sequence of the helper plasmid in the present invention, and a protein cDNA are arranged. It can also include one or more nucleic acid sequences encoding (eg trans-acting factors), chaperones, processing proteases. It may also have any factor that is functional in the selected cell.
- the helper plasmid is preferably constructed using a commercially available plasmid vector capable of self-replication in a cell into which the helper plasmid is introduced.
- Examples of commercially available plasmid vectors include pCAGGS, pCXN2, and pCDNA3.1. It is done.
- the promoter sequence in the helper plasmid is preferably an RNA polymerase II type promoter.
- helper plasmids can be prepared by a known genetic engineering technique.
- a plasmid that expresses the N gene of BDV a plasmid that expresses the P gene of BDV, and a plasmid that expresses the L gene of BDV are described in “Materials and” of Yanai et al., Microbes and Infection 8 (2006), 1522-1529. It can be prepared by the method described in 2.2 Plasmid construction of “methods”.
- the plasmid expressing the N gene and the P gene of BDV for example, from the unique restriction enzyme sequence region downstream of the cDNA of the N gene of the plasmid expressing the N gene of BDV, the signal sequence such as cDNA and promoter of N gene It can be prepared by appropriately selecting a restriction enzyme that does not cut and inserting the BDV P gene cDNA into the restriction enzyme site.
- a plasmid expressing the N gene and L gene of BDV is, for example, a signal sequence such as a cDNA or promoter of the N gene from a unique restriction enzyme sequence region downstream of the cDNA of the N gene of the plasmid expressing the N gene of BDV.
- It can be prepared by appropriately selecting a restriction enzyme that does not cleave and inserting BDV L gene cDNA into the restriction enzyme site.
- a sequence such as a promoter sequence that promotes the expression of the L gene or the P gene or an internal ribosome entry site It is also possible to insert.
- a plasmid expressing the BDV G gene is prepared by using a BDV G gene cDNA in place of the BDV N gene cDNA in the production of a helper plasmid expressing the BDV N gene, L gene or P gene. be able to. For example, it can be manufactured according to the method shown in Example 7 and FIG. 21 as an example.
- a plasmid expressing the M gene of BDV can be prepared, for example, according to the method described in the instructions attached to pEF4 / myc-His A, B, and C (Invitrogen).
- a helper plasmid that encodes the extracellular sequence and transmembrane sequence of the outer shell protein of a virus other than BDV and expresses the outer shell gene encoding the intracellular sequence of the G protein of BDV is, for example, an outside of a virus other than BDV.
- a plasmid that expresses the shell gene as a template PCR is performed using appropriate primers, and the sequence encoding the intracellular sequence of any viral outer shell gene is replaced with the sequence encoding the intracellular sequence of the BDV G protein. It can produce by doing.
- Such a helper plasmid can also be prepared, for example, according to the method described in Example 8 and FIG.
- the gene sequence encoding the intracellular sequence of the G protein of BDV is, for example, the 3712-3747th sequence (the 3712-3747th base of SEQ ID NO: 1) in the BDV genome whose cDNA sequence is shown in SEQ ID NO: 1.
- a vector composition containing the virus vector can be used.
- the vector composition may contain a helper plasmid in addition to the viral vector.
- the vector composition contains other components such as an appropriate buffer solution, phosphate buffered saline, cell culture standard solution, etc., depending on the introduction method and introduction target. May be.
- the content of the viral vector in the vector composition may be appropriately selected according to the infection method, the infection target, and the like, and includes, for example, a viral vector having a DNA concentration of about 0.25 to 2.0 ⁇ g / ⁇ L. It is preferable.
- each helper plasmid in the vector composition is preferably about 0.0125 to 0.125 ⁇ g per 1 ⁇ g of the virus vector.
- the method for introducing the viral vector and the helper plasmid into cells in vitro is not particularly limited, and for example, a method known per se using a commercially available transfection reagent can be employed.
- commercially available transfection reagents include, but are not limited to, FuGENE 6 transfection reagent (Roche Molecular Diagnostics (registered trademark), Pleasanton, CA).
- FuGENE 6 transfection reagent FuGENE 6 transfection reagent
- an appropriate amount of a commercially available transfection reagent is added to a vector composition containing the above-mentioned amounts of virus vector and helper plasmid, buffer, and the like, and this is usually about 10 3 to 10 per 1 ⁇ g of virus vector.
- a viral vector and a helper plasmid can be introduced into the cells by adding about 10 4 to 10 7 cells.
- the viral vector and helper plasmid may be introduced into the cell at the same time or may be introduced separately.
- the order of introduction when separately installed is not particularly limited.
- the cell into which the viral vector is introduced may be any mammalian cultured cell that can produce the recombinant virus of the present invention by introducing the viral vector, and examples thereof include human kidney-derived 293T cells and BHK cells. It is done.
- a cell that constantly expresses the outer shell gene used in the helper plasmid that expresses the outer shell gene can be prepared by introducing the outer shell gene into cells such as 293T cells and BHK cells using various plasmids that express the outer shell gene.
- a plasmid that expresses the outer shell gene is usually produced by introducing the outer shell gene into the plasmid according to the method described in the instructions attached to the various expression plasmids.
- the above-mentioned helper plasmid expressing the outer shell gene can also be suitably used.
- the G gene and M gene deficient viral vectors are used, it is preferable to use cells that constantly express the outer shell gene used in the helper plasmid that expresses the M gene and outer shell gene of BDV.
- Such cells are produced, for example, by introducing the BDV M gene and the outer shell gene into cells such as 293T cells and BHK cells in the same manner.
- the plasmid expressing the outer shell gene and the plasmid expressing the BDV M gene are usually easily prepared by introducing the outer shell gene and the BDV M gene into the plasmid according to the instructions attached to the various expression plasmids. Manufactured.
- the above-described helper plasmid expressing the outer shell gene, the helper plasmid expressing the BDV M gene, and the like can be preferably used.
- the culture conditions such as the medium for producing the recombinant virus, the culture temperature, and the culture time may be appropriately set depending on the cell type.
- the culture temperature is usually about 36 to 37 ° C. when 293T cells or BHK cells are used.
- the medium Dulbecco's modified Eagle MEM medium is preferably used.
- the culture time is usually about 24 to 96 hours, preferably about 36 to 48 hours.
- the above culture produces a recombinant virus containing RNA encoded by the viral vector and BDV N, P, and L proteins in the cells into which the viral vector has been introduced.
- BDV helper plasmid that expresses the viral outer gene
- a recombinant virus containing the outer protein encoded by the gene is produced.
- helper plasmid that expresses the outer gene of the virus and a helper plasmid that expresses the M gene of BDV are used in the introduction of the virus vector, the RNA encoded by the virus vector, and the N protein and P protein of BDV In addition to the L protein and the L protein, a recombinant virus containing the outer shell protein encoded by the outer shell gene and the M protein of BDV is produced.
- Recombinant virus is produced in the cells into which the viral vector has been introduced.
- the supernatant of the culture medium in which the cells are cultured is collected by centrifugation or the like, and BDV is used to infect cells such as monkeys. It is confirmed by infecting kidney-derived Vero cells, rat glia-derived C6 cells, human glia-derived OL cells and the like. Confirmation that the recombinant virus has been produced may be carried out after performing a step of mixing and culturing the cells producing the recombinant virus described later with cells having a high growth rate. For example, a recombinant virus can be confirmed by quantitative analysis of the expression of a foreign gene (such as GFP) in an infected cell.
- a foreign gene such as GFP
- That the produced virus is a persistent infectious type is that the expression of a foreign gene (such as GFP) in an infected cell is quantitatively analyzed and the next generation of recombinant virus is contained in the culture supernatant. This is confirmed by examining the production of particles.
- the production of particles of the next generation recombinant virus in the culture supernatant means, for example, that the supernatant is recovered by centrifugation, etc., and this is further infected to other cells. This can be confirmed by examining the expression of a foreign gene derived from s.
- the cell producing the recombinant virus in order to efficiently propagate the recombinant virus (for example, it is preferable to perform a step of mixing and culturing 293T cells and BHK cells) with cells having a high growth rate.
- the infectious recombinant virus infects the cells having a high growth rate.
- the infected virus grows with the growth of the cells, so that the recombinant virus can be efficiently propagated.
- the cell having a high proliferation rate for example, Vero cell is suitable.
- the mixing ratio of the cells that have produced the recombinant virus and the cells having a high growth rate is, for example, usually about 0.1 to 10 cells having a high growth rate with respect to one cell that has produced the recombinant virus. Preferably about 0.2 to 2.
- Conditions for culturing cells having a high growth rate after mixed culture are not particularly limited.
- the culture temperature is usually about 36 to 37 ° C., and usually 3 times with Dulbecco's modified Eagle MEM medium. Culturing is carried out for about 5 days, preferably about 3 days to 3 weeks.
- a G gene-deficient virus vector When a G gene-deficient virus vector is used, it is preferable to use a cell that constantly expresses the outer shell gene used in the helper plasmid that expresses the outer shell gene as a cell having a high growth rate.
- a cell can be prepared by introducing the gene into a cell such as a Vero cell using a plasmid that expresses the coat gene.
- the outer shell gene using the helper plasmid that expresses the outer shell gene and the M gene of BDV are constantly expressed as cells having a high growth rate. It is preferred to use cells.
- Such cells can be prepared, for example, by introducing a gene expressing an outer shell gene and a plasmid expressing the M gene of BDV into a Vero cell or the like.
- the plasmid expressing the outer shell gene and the plasmid expressing the BDV M gene are usually easily prepared by introducing the outer shell gene and the BDV M gene into the plasmid according to the instructions attached to the various expression plasmids. Manufactured.
- the plasmid expressing the outer shell gene and the plasmid expressing the BDV M gene the above-described helper plasmid expressing the outer shell gene, the helper plasmid expressing the BDV M gene, and the like can be preferably used.
- the production method of the present invention it is preferable to carry out a step of purifying the recombinant virus after the cell is produced (and propagated). It does not specifically limit as a purification method, It can carry out by a publicly known method, What is necessary is just to select the purification method suitably according to the infection object of a recombinant virus.
- the recombinant virus is produced (and propagated) as described above, and then the culture cell supernatant producing the recombinant virus is recovered, Crush.
- Cell disruption can be performed using, for example, freezing and thawing, or an ultrasonic disrupter.
- cell disruption components are removed from the cell disruption solution. Examples of the method for removing the cell disruption component from the cell disruption solution include centrifugation (for example, at 4 ° C. and 800 g for about 10 minutes).
- a supernatant containing the recombinant virus can be obtained by passing through a filtration membrane having a pore size of 0.22 or 0.45 ⁇ m.
- This supernatant can be used when the cultured cells are infected with the recombinant virus.
- the supernatant containing this recombinant virus can also be concentrated and used by a known technique.
- the supernatant containing the recombinant virus is highly converted into virus particles by ultracentrifugation using a concentration centrifuge using an ultracentrifuge. It is preferable to carry out purification.
- the purified virus particles are suspended in, for example, phosphate buffered saline, diluted, and then the animal is infected with an appropriate amount.
- Method for introducing a foreign gene By infecting a cell with the above recombinant virus, a foreign gene incorporated into the virus can be introduced into a cell or a living body.
- a method for introducing an exogenous gene comprising the step of infecting cells or animals in vitro with the above-described recombinant virus or the recombinant virus produced by the above-described method is also one aspect of the present invention.
- the animal infected with the recombinant virus is not particularly limited, and examples thereof include mammals, birds, reptiles and amphibians. Among them, mammals such as humans, monkeys, horses, dogs, cats, pigs, sheep, goats, rats, mice, rabbits and cows are preferable, rats, mice or humans are more preferable, and mice or humans are more preferable.
- Such animal cells are preferred as the cells to be infected with the recombinant virus.
- BDV is more preferably a mammalian nervous system cell due to its infection-directed ability to the nervous system cell, and particularly preferably a cerebral nervous system cell. Of these, rat, mouse or human nervous system cells are preferred.
- the cell may be a cultured cell or a living cell.
- mammalian cerebral nervous system cells include glial cells, cerebral cortex neurons, hippocampal neurons, cerebellar neurons, and midbrain neurons.
- cultured cells of mammalian brain neurons OL, C6, U373, N2a, N18, PC12, SK-N-SH cells and the like are suitable.
- Recombinant virus produced using a G gene-deficient virus vector and a plasmid that expresses the outer gene of the virus as a helper plasmid exhibits an infection direction depending on the type of virus from which the outer gene is derived.
- the resulting recombinant virus is preferably used for introducing a foreign gene into a brain neuron because it exhibits an infection-directed property to a brain nervous system cell.
- Viral shell genes other than BDV in the helper plasmid preferably, the outer shell genes encoding the extracellular and transmembrane sequences of viral outer proteins other than BDV and the intracellular sequence of BDV G protein
- the resulting recombinant virus can suitably infect cells in which the virus is directed against infection.
- the supernatant containing the recombinant virus obtained by the purification method described above is used as a culture medium such as Dulbecco's modified Eagle or the like. It is preferable to prepare a diluted solution by serial dilution with phosphate buffered saline or the like. The concentration of the recombinant virus in the diluted solution may be appropriately selected depending on the type of cells to be infected with the virus.
- the MOI multiplicity of infection value
- the MOI is usually about 0.01 to 10 (amount that 0.01 to 10 virus particles infect one cell), preferably about 1 to 10 MOI.
- This diluted solution is used to infect cells with the recombinant virus.
- the virus particles highly purified as described above are suspended in, for example, phosphate buffered saline and diluted with the phosphate buffered saline. It is preferred to infect the animal with an appropriate amount after doing so.
- concentration of the recombinant virus in the diluted solution may be appropriately selected depending on the infection target. For example, if the target of infection is a mammalian nerve cell, it is preferable to inoculate an individual with a virus-titer (focus-forming unit (FFU)) of a diluted solution containing a recombinant virus at about 10 ⁇ 1 to 10 9 FFU. .
- FFU focus-forming unit
- the virus titer when a diluted solution containing a recombinant virus is inoculated into mice or rats, the virus titer is preferably about 10 ⁇ 1 to 10 7 FFU. Dogs or cats, when inoculated into humans, it is preferred that the viral titers and usually about 10 ⁇ 10 8 FFU, when inoculated into cattle or horses, virus titer normally 10 5 ⁇ 10 12 FFU It is preferable that When inoculating humans, the virus titer is preferably about 10 5 to 10 9 FFU. Further, when infecting a living cell with a recombinant virus, an exogenous gene transfer agent described later can also be suitably used.
- a mammalian cerebral nervous system cell when infected with a recombinant virus, a method of inoculating a mammalian nasal cavity with a diluent containing the recombinant virus is preferable.
- a dilution solution containing a recombinant virus when infecting cranial nervous system cells in mice or rats in animal experiments, a dilution solution containing a recombinant virus can be directly inoculated into the brain of the animal.
- the diluted solution containing the above-mentioned concentration of the recombinant virus is usually inoculated in an amount of about 5 ⁇ L to 1 mL at a time for intranasal inoculation, and usually about 1 to 50 ⁇ L at a time for inoculation in the brain.
- the inoculation amount of the recombinant virus to the animal may be appropriately selected according to the body weight or the like of the animal.
- a mouse or rat when a mouse or rat is inoculated intranasally with a diluted solution containing the above-mentioned concentration of the recombinant virus, 1 Usually about 5 to 200 ⁇ L, preferably about 10 to 100 ⁇ L is inoculated per time.
- a diluent containing the above recombinant virus When infecting a living cell other than a brain nerve cell with a recombinant virus, it is preferable to parenterally administer a diluent containing the above recombinant virus.
- a method of inoculating a mammal into the abdominal cavity, blood vessel, muscle or the like is suitable.
- the inoculation amount of the recombinant virus may be appropriately selected depending on the inoculation site and the like, and is not particularly limited.
- the virus titer of the diluted solution containing the recombinant virus is usually about 10 ⁇ 1 to 10 9 FFU, and the diluted solution containing the recombinant virus is usually about 5 to 500 ⁇ L at a time for mice, preferably Inoculate approximately 20-200 ⁇ L.
- An exogenous gene introduction agent (1) The above-described viral vector, or (2) the above-described recombinant virus, or an exogenous gene introduction agent containing a recombinant virus prepared by the above method is also one aspect of the present invention.
- a preferred embodiment is an exogenous gene transfer agent containing the above recombinant virus or the recombinant virus prepared by the above method.
- Such an exogenous gene introduction agent can be suitably used when infecting a recombinant virus with an in vitro cell or a living cell (animal) in the aforementioned exogenous gene introduction method.
- the present invention can be suitably used for introducing a foreign gene into an animal nervous system cell or the like. Among them, it is preferably used by introducing a foreign gene into a cerebral nervous system cell.
- One of the preferred embodiments of the exogenous gene introduction agent of the present invention is an exogenous gene introduction agent into a cranial nervous system cell containing the above recombinant virus or a recombinant virus produced by the above method.
- the cranial nervous system cells are preferably mammalian cerebral nervous system cells such as glial cells, cerebral cortex neurons, hippocampal neurons, cerebellar neurons, and midbrain neurons.
- the exogenous gene transfer agent of the present invention may further contain other drugs such as a therapeutic agent for neurological diseases, and may contain pharmaceutically acceptable components depending on the dosage form.
- a dosage form for parenteral administration is preferable. For example, injection, instillation, ointment, gel, cream, patch, spray, spray An injection is preferable.
- an aqueous injection As an injection for parenteral administration, either an aqueous injection or an oily injection may be used.
- an aqueous injection according to a known method, for example, after mixing the recombinant virus with a solution obtained by appropriately adding a pharmaceutically acceptable additive to an aqueous solvent (water for injection, purified water, etc.), a filter or the like It can be prepared by sterilizing by filtration and then filling into a sterile container.
- a aqueous solvent water for injection, purified water, etc.
- Examples of pharmaceutically acceptable additives include isotonic agents such as sodium chloride, potassium chloride, glycerin, mannitol, sorbitol, boric acid, borax, glucose, propylene glycol; phosphate buffer, acetate buffer, Buffers such as borate buffer, carbonate buffer, citrate buffer, Tris buffer, glutamate buffer, epsilon aminocaproate buffer; methyl paraoxybenzoate, ethyl paraoxybenzoate, propyl paraoxybenzoate, paraoxybenzoic acid Preservatives such as butyl, chlorobutanol, benzyl alcohol, benzalkonium chloride, sodium dehydroacetate, sodium edetate, boric acid, borax; thickeners such as hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyethylene glycol; Sodium bisulfate, sodium thiosulfate, sodium edetate, sodium citrate, ascorbic acid,
- solubilizers for example, alcohols such as ethanol; polyalcohols such as propylene glycol and polyethylene glycol; nonionic surfactants such as polysorbate 80, polyoxyethylene hydrogenated castor oil 50, lysolecithin, and pluronic polyol You may mix
- proteins such as bovine serum albumin and keyhole limpet hemocyanin; polysaccharides such as aminodextran may be contained.
- sesame oil or soybean oil is used as the oily solvent, and benzyl benzoate or benzyl alcohol may be blended as a solubilizing agent.
- the prepared injection solution is usually filled in an appropriate ampoule or vial.
- Liquid preparations such as injections can be stored after removing moisture by freezing or lyophilization.
- the freeze-dried preparation is used by adding distilled water for injection at the time of use and re-dissolving it.
- the amount of the recombinant virus contained in the exogenous gene transfer agent of the present invention varies depending on the preparation form or administration route of the exogenous gene transfer agent, but is usually appropriately within the range of about 0.0001 to 100% in the final preparation. You can select and decide.
- the administration method and dosage of the exogenous gene introduction agent are the same as the method in the above-described exogenous gene introduction method and the dosage of the recombinant virus.
- the exogenous gene transfer agent of the present invention is useful as a gene delivery composition for, for example, treatment of cranial nervous system diseases in animals, chronic liver diseases such as hepatitis C, antitumor drugs, vaccines and the like.
- the mammal described above is suitable for the administration target of the exogenous gene transfer agent of the present invention.
- the viral vector, recombinant virus and foreign gene introduction method of the present invention, and the foreign gene introduction agent can be applied to various fields as gene introduction techniques that do not affect the host chromosome. It is.
- the viral vector and recombinant virus of the present invention can be used as a gene delivery vector for treating cranial nervous system diseases in animals including humans. It can also be suitably used for vaccines against chronic liver diseases, tumors, infectious diseases and the like. Examples of the cranial nervous system diseases include Alzheimer's disease, Parkinson's disease, multiple sclerosis, schizophrenia, autism, and other functional psychiatric diseases.
- the recombinant virus of the present invention is useful for the treatment or prevention of such diseases.
- an exogenous gene in the viral vector of the present invention is a gene of an enzyme that degrades a protein causing a cranial nervous system disease
- a nucleic acid sequence having a function of suppressing the expression of the protein, or the like, produced from the viral vector By infecting brain neurons with the recombinant virus to be produced, the causative protein can be decomposed or the expression of the causative protein can be suppressed to prevent or treat the disease.
- a gene that encodes the substance in the brain is inserted into a viral vector, and a combination produced from the viral vector. By infecting brain neurons with the virus, the substance in the brain is produced, so that the disease can be prevented or treated.
- Treatment refers to not only completely curing the disease state, but also suppressing the progression and / or worsening of symptoms without complete cure, and stopping the progression of the disease state, or part or all of the disease state “Preventing” means to prevent, suppress, or delay the onset of a disease state, respectively, to improve the condition and lead to the direction of healing.
- the virus vector and recombinant virus of the present invention can also be used for treatment or prevention of viral encephalitis such as Japanese encephalitis.
- it can also be suitably used for cranial nervous system diseases of laboratory animals, companion animals or production animals such as BSE (bovine spongiform encephalopathy), rabies and the like.
- BSE bovine spongiform encephalopathy
- Examples of experimental animals include mice, rats, guinea pigs, rabbits, cats and dogs.
- companion animals include mice, rats, guinea pigs, rabbits, cats, and dogs.
- production animals include cattle, horses, pigs and sheep.
- the virus vector and the recombinant virus of the present invention can be used for visualization technology of nervous system cells in the field of neuroscience.
- the viral vector of the present invention is also useful as an RNA viral vector capable of expressing a functional RNA molecule, and can also be applied to a technique for stably expressing functional RNA such as siRNA, miRNA, RNA aptamer.
- a sequence encoding a functional RNA such as siRNA, miRNA, RNA aptamer or the like is used as a foreign gene in the virus vector of the present invention, these functional RNA molecules can be expressed in a desired cell.
- a single chain antibody (scFv) can be expressed in the brain.
- the virus vector or recombinant virus that specifically infects tumor cells is improved, and siRNA that suppresses drug genes and overexpressed genes into tumor cells is introduced. By doing so, it can also be used as an anti-tumor virus vector.
- a gene having neutralizing activity against HIV, influenza virus, etc. eg, HIV env, gag, etc .; influenza virus HA, NA gene, etc.
- recombinant viruses for recombinant vaccines for infectious diseases that follow the chronic course such as HCV, siRNA against the target virus genome is introduced, which is effective for the development of new treatments for infectious diseases using functional RNA. .
- kits of the present invention may appropriately include a helper plasmid, a cell into which an exogenous gene is introduced, a buffer solution, a medium and the like in addition to the viral vector.
- a preferred embodiment of the viral vector is as described above.
- the cell into which the foreign gene is introduced is preferably a nervous system cell such as a cerebral nervous system cell.
- the kit of the present invention can be suitably used for introducing an exogenous gene into a brain nervous system cell or the like, which has been technically difficult until now.
- Example 1 Preparation of plasmid pCAG-Fct Chloramphenicol acetyltransferase inserted into plasmid pCAG-HR-SV3 described in Yanai et al., Microbes and Infection 8 (2006), 1522-1529
- a plasmid in which the region of (CAT) gene was replaced with the sequence of the genome of Borna disease virus He / 80 strain (SEQ ID NO: 1) was prepared as follows.
- a BDV minigenome vector derived from cytomegavirus (CMV)
- CMV cytomegavirus
- a chemically synthesized oligonucleotide (Briese et al., Proc. Natl. Acad. Sci. USA) encoding hammerhead ribozyme (HamRz) 89 (1992) 11486-11489, and Le Mercier et al., J. Virol., 76 (2002) 2024-2027) and chemically synthesized oligonucleotides encoding the 5 'untranslated region (UTR) sequence of BDV (Cubitt, B., Oldstone, C. And de la Torre, JC, Sequence and genome organization of Borna disease virus.
- UTR 5 'untranslated region
- pCMV-HR was prepared by inserting the BglII and XbaI fragments of pc-HR into the BamHI and XbaI sites of pBluescript SKII (-) (Stratagene, La Jolla, CA).
- the BDV minigenomic vector pCAG-HR derived from CAG was obtained by subcloning the CAG promoter into pBluescript SKII (-) (Stratagene, La Jolla, CA) ( pBS-CAG).
- the CAG promoter is a hybrid promoter obtained by fusing a chicken ⁇ -actin promoter with a cytomegalovirus IE enhancer, and is described in Sawichi et al., “Exp.” Cell “Res.” 244 (1998) 367-369.
- a region spanning the HamRz and HdRz sequences of pCMV-HR was amplified by PCR and inserted into the blunt ends of the SalI and EcoRI sites of pBS-CAG.
- SV3 region consisting of 113 bases on the 5 ′ side within the SV40 starting point / promoter was amplified from pEGFP-N1 (Clontech) by PCR (Clontech Laboratory, Inc., Palo Alto, CA). And inserted into the NotI site of pCAG-HR. This resulted in plasmid pCAG-Fct.
- BDV genomic plasmid (pCAG-Fct-P / MGFP) with GFP inserted in the untranslated region between P gene and M gene Insert a foreign gene insertion cassette into the untranslated region between P gene and M gene Plasmid pCAG-Fct-P / M was prepared.
- pCAG-Fct plasmid in which cDNA of He80 strain of Bornavirus (SEQ ID NO: 1)
- Primer 1 5-GGAATGCATTGACCCAACCGGTAGACCAGC-3 (SEQ ID NO: 5)
- Primer 2 5-AACATGTATTTCCTAATCGGGTCCTTGTATACGG-3 (SEQ ID NO: 6)
- Primer 3 5-ttcgaaGGTTGGttaattaaccataaaaaatcgaatcacc-3 (SEQ ID NO: 7)
- Primer 4 5-ttaattaaCCAACCttcgaaGGTGATTCGATTTTTTTATGG-3 (SEQ ID NO: 8)
- Helper plasmids ie, BDV N gene expression plasmid (pcN), BDV P gene expression plasmid (pCXN2-P) and BDV L gene expression plasmid (pcL) were prepared by the following procedure.
- pcN is a pHA-p40N plasmid (Kobayashi T, Watanabe M, Kamitani W, Zhang G, Tomonaga K and Ikuta K. Borna disease virus nucleoprotein requires both nuclear localization and export activities for viral nucleocytoplasmic shuttling. J. Virol. 75: 3404- From 3412.
- Plasmid pCXN2-P is a pcD-P (Zhang G, Kobayashi T, Kamitani W, Komoto S, Yamashita M, Baba S, Yanai H, Ikuta K and Tomonaga K. Borna disease virus phosphoprotein represses p53-mediated transcriptional activity by interference with HMGB1. J. Virol. 77: 12243-12251. (2003)) pCXN2 (Niwa H, Yamamura K, Miyazaki J 1991 Efficient selection for high-expression transfectants with a novel eukaryotic vector.
- pcL was prepared by the method described in Perez et al., J. Gen. Virol. 84 (2003) 3099-3104. The nucleotide sequence of the recombinant plasmid was confirmed by DNA sequencing.
- Example 2 Construction and characterization of BDV vectors using PM gene plasmids pCAG-Fct-P / M-GFP and helper plasmids (N gene expression plasmid, P gene expression plasmid and L gene expression plasmid; pcN, pCXN2-P, respectively) And pcL) were introduced into 293T cells using FuGENE 6 transfection reagent (Roche Molecular Diagnostics (registered trademark), Pleasanton, CA) or Lipofectamine (registered trademark) 2000, Invitrogen).
- the amount of viral vector used for the introduction was 1 to 4 ⁇ g of pCAG-Fct-P / M-GFP for 10 4 to 10 6 cells (293T cells), and pcN (0.125 to 0 0.5 ⁇ g), pCXN2-P (0.0125 to 0.05 ⁇ g), pcL (0.125 to 0.5 ⁇ g) at a ratio of helper plasmid.
- the 293T cells were cultured in Dulbecco's modified Eagle's medium at 37 ° C. for 48 hours, and the supernatant was collected, centrifuged at 800 g for 10 minutes, and filtered through a 0.22 to 0.45 ⁇ m filter.
- a recombinant virus expressing GFP hereinafter also referred to as recombinant virus p / mGFP was purified.
- the vector rBDV-5′GFP prepared in Reference Example 1 was also introduced into 293T cells in the same manner as described above to prepare a recombinant virus (hereinafter also referred to as recombinant virus 5′GFP).
- the recombinant virus was then purified.
- wild-type BDV hereinafter also referred to as wt
- wild type BDV wt
- purified recombinant viruses p / mGFP and 5'GFP were added to M.
- the indirect immunofluorescence antibody method was performed by the following method.
- Anti-BDV N antibody and anti-BDV M antibody were analyzed by Watanabe M, Zhong Q, Kobayashi T, Kamitani W, Tomonaga K, Ikuta K. Molecular ratio between Borna disease viral-p40 and -p24 proteins in infected cells determined by quantitative antigen capture ELISA Microbiol Immunol. 2000. 44: 765-72, Chase G, Mayer D, Hildebrand A, Frank R, Hayashi Y, Tomonaga K, Schwemmle M.
- Borna disease virus matrix protein is an integral component of the viral ribonucleoprotein complex that does not It was produced according to the method described in J Virol. 2007. 81: 743-749.
- Vero cells each infected with wild-type BDV and each recombinant virus were collected after culturing for a certain number of days after infection, fixed on a glass plate, and this was combined with anti-BDV N antibody (with phosphate buffer, Anti-BDV N antibody diluted to 0.2-5 ⁇ g / mL) or anti-BDV M antibody (diluted with phosphate buffer to anti-BDV M antibody concentration of 0.2-5 ⁇ g / mL) at 37 ° C. The reaction was carried out for about 1 hour.
- FIG. 5 is a diagram showing the results of examining the time course of the infection rate of Vero cells infected with wild type or recombinant BDV from day 0 to day 19 after infection.
- the infection rates shown in FIG. 5 are as follows: for wild-type BDV, by the indirect immunofluorescence antibody method using the fluorescence of the fluorescence-labeled antibody against anti-BDV N antibody as an index, and for recombinant BDV, against GFP fluorescence and anti-BDV N antibody. Each was determined by the indirect immunofluorescence antibody method using the fluorescence of the fluorescently labeled antibody as an index.
- FIG. 5 is a diagram showing the results of examining the time course of the infection rate of Vero cells infected with wild type or recombinant BDV from day 0 to day 19 after infection.
- the infection rates shown in FIG. 5 are as follows: for wild-type BDV, by the indirect immunofluorescence antibody method using the fluorescence of the fluorescence-labeled antibody against anti
- wt (diamond: ⁇ ) represents the wild-type BDV
- p / mGFP square: ⁇
- 5′GFP (triangle: ⁇ ) represents the group prepared in Reference Example 1.
- the replacement virus 5′GFP is shown respectively. From FIG. 5, about 15 days after infection, both the recombinant viruses p / mGFP and 5'GFP were almost 100% infected with Vero cells, like wild-type BDV. From this, it was found that both the recombinant viruses p / mGFP and 5'GFP have the same virus production ability as wild-type BDV.
- FIG. 6 shows the result of Northern blot.
- wt represents wild-type BDV
- p / m represents recombinant virus p / mGFP
- 5 ′ represents recombinant virus 5′GFP.
- u. i. Indicates uninfected cells.
- FIG. 6 (a) shows the results of examining the expression levels of BDV N gene (upper figure) and GFP gene (middle figure) in Vero cells 19 days after infection by Northern blotting.
- FIG. 6 (a) shows that the gene for the viral protein (N protein) is expressed to the same degree in any cell infected with BDV.
- the lower diagram of FIG. 6A is a visualization of the ribosomal RNA contained in the sample after electrophoresis in order to quantify the amount of RNA used in the analysis.
- FIG. 6 (b) shows BDV N protein (topmost), P protein (second from the top), M protein (third from the top) and GFP (bottom) in Vero cells 19 days after infection. It is a figure which shows the result of having investigated the expression level by the Western blot.
- FIG. 6 (b) shows that the viral proteins (N protein, P protein, and M protein) are expressed to the same extent in any cell infected with BDV.
- GFP / N protein 0.58 in the cells that were allowed to escape. It can be seen that the expression rate of the GFP gene relative to the infected virus is higher in the recombinant virus p / mGFP than in the recombinant virus 5'GFP.
- FIGS. 7a-f are photomicrographs of cells infected with wild type BDV, recombinant virus p / mGFP and recombinant virus 5'GFP, respectively.
- 7a and b are cells infected with wild type BDV
- c and d are cells infected with recombinant virus p / mGFP
- e and f are cells infected with recombinant virus 5′GFP.
- FIGS. 7a, c and e show the results of investigating viral infection of cells by the indirect immunofluorescence antibody method using an N protein antibody (anti-BDV N antibody) and a fluorescently labeled antibody (manufactured by Molecular Probes). .
- anti-BDV N antibody an anti-BDV N antibody
- a fluorescently labeled antibody manufactured by Molecular Probes.
- FIGS. 7a, c and e the luminescent portion (red) is N protein.
- FIGS. 7b, d and f show the results of examining the expression of a foreign gene (GFP) by the virus by the fluorescence of the protein (green fluorescence). In FIGS. 7b, d and f, GFP is detected by green fluorescence. From FIGS. 7a to f, it can be seen that the N protein is expressed to the same degree in any of the cells infected with BDV virus, so that the replication ability of the virus is the same.
- GFP foreign gene
- the fluorescence intensity of GFP is significantly higher in cells infected with the recombinant virus p / mGFP than the recombinant virus 5′GFP, the recombinant virus p / mGFP is expressed in foreign genes (GFP). It can be seen that the efficiency is significantly higher than that of the recombinant virus 5′GFP.
- FIGS. 8a-f are photomicrographs of cells infected with wild type BDV, recombinant virus p / mGFP and recombinant virus 5'GFP, respectively.
- 8a and b are cells infected with wild type BDV
- c and d are cells infected with recombinant virus p / mGFP
- e and f are cells infected with recombinant virus 5′GFP.
- FIGS. 8a, 8c and 8e show the results of investigating viral infection of cells by the indirect immunofluorescence antibody method using M protein antibody (anti-BDV M antibody) and fluorescently labeled antibody (manufactured by Molecular Probes). .
- FIGS. 8b, d and f show the results of examining the expression of a foreign gene (GFP) by the virus by the fluorescence of the protein (green fluorescence).
- GFP foreign gene
- FIGS. 8a, c and e the luminescent portion (red) is the M protein.
- FIGS. 8b, d and f GFP is detected by green fluorescence.
- FIGS. 8a to 8f show that the M protein is expressed at the same level in any of the cells infected with BDV virus, indicating that the replication ability of the virus is the same.
- the recombinant virus p / mGFP has a combined expression efficiency of foreign genes. It can be seen that it is significantly higher than the replacement virus 5′GFP.
- Example 3 The rat brain was infected with the recombinant virus p / mGFP produced in Example 2 and the recombinant virus 5′GFP produced in Reference Example 1, respectively.
- Each purified recombinant virus was diluted to 10 3 FFU with PBS or a culture medium, and then inoculated into 10 to 20 ⁇ L from the left temporal region into the skull of a neonatal rat within 24 hours after birth (FIG. 9). Samples were taken 7, 14, and 21 days after inoculation, and the brain was divided into regions as shown in FIG. 10, and DNA was extracted from each region (using a Qiagen DNA extraction kit). The recombinant virus infection was checked by PCR and GFP expression.
- the PCR product was confirmed by 1% agarose electrophoresis.
- the recombinant virus was detected not only in the inoculation site but also in the cerebral cortex (anterior part of the right brain in FIG. 10) and the cerebellar region (the posterior part of the right brain in FIG. 10). It was done.
- FIG. 11 shows the results of electrophoresis of the PCR product.
- the lane labeled p / mGFP is a PCR product from rat brain infected with recombinant virus p / mGFP.
- Lanes labeled 5'GFP are PCR products from rat brain infected with recombinant virus 5'GFP.
- a is a cerebral cortex and b is a PCR product of cerebellar DNA.
- all the bands detected in FIG. 11 are bands of the BDV genomic fragment amplified by the PCR, the region between the P gene and the M gene of BDV is amplified when the PCR is performed. .
- the recombinant virus p / mGFP since the GFP gene is included between the P gene and the M gene, a band is detected on the higher molecular weight side than the PCR product of the recombinant virus 5'GFP.
- I in FIG. 11 is a wild-type BDV-infected Vero cell, and U is an uninfected cell. This result indicated that the inoculated recombinant virus spread to other parts of the brain.
- FIG. 12 shows a macro photograph (a and b) in which the rat brain 14 days after inoculation was cut open and turned over, and a macro fluorescence photograph (c and d) of the brain, respectively.
- GFP fluorescent moiety
- FIGS. 12c and d it is GFP in which the fluorescent moiety is expressed.
- the fluorescence intensity of GFP is significantly higher in the cerebral cortex of the brain infected with the recombinant virus p / mGFP than the recombinant virus 5′GFP, the recombinant virus p / mGFP is used. It can be seen that the expression efficiency of the foreign gene is significantly higher than that of the recombinant virus 5′GFP.
- FIGS. 13a to 13d are micrographs of cerebral cortex sections (shown in the upper part of FIGS. 13a to 13d and indicated by squares in the photograph).
- FIGS. 13a and 13c show the expression of N gene in the cerebral cortex of rats 7 days after inoculation, the same antibody against N protein (anti-BDV N antibody) and fluorescently labeled antibody (manufactured by Molecular Probe) as in Example 2.
- the result investigated by the indirect immunofluorescence antibody method using is shown.
- the N protein is detected by red fluorescence, and the same amount of N protein is expressed when the recombinant virus p / mGFP or the recombinant virus 5′GFP is infected (the virus infection amount is the same). It was found that.
- FIGS. 13a and 13c show the results of fluorescence detection of GFP expression in the same sections as in FIGS. 13a and 13c, respectively.
- the fluorescence intensity of GFP is significantly higher in the cerebral cortex of the brain infected with the recombinant virus p / mGFP (FIG. 13b) than in the cerebral cortex of the brain infected with the recombinant virus 5′GFP (FIG. 13d). It was big.
- Example 4 a recombinant vector (rBDV-p / mDsRed vector) in which a DsRed gene was inserted into the untranslated region between the P gene and the M gene using a DsRed gene (manufactured by Clontech) instead of the GFP gene. ) And a recombinant virus was prepared in the same manner as in Example 2. As a comparison, a recombination vector (rBDV-5′DsRed vector) in which the DsRed gene was inserted into the 5 ′ end of the BDV genome using the DsRed gene instead of the GFP gene in Reference Example 1 was prepared. In this way, a recombinant virus was produced.
- the cells were infected with the recombinant virus and the DsRed gene was expressed on the 10th day using the same antibody against N protein (anti-BDV N antibody) as in Example 2 and As shown in FIG. 14, in the cells infected with the recombinant virus produced from the rBDV-p / mDsRed vector, an indirect immunofluorescence antibody method using a fluorescently labeled antibody (manufactured by Molecular Probes) was used. N protein expression (FIG. 14 (a)) and DsRed expression (FIG. 14 (b)) were observed (N protein was detected by the secondary antibody with green fluorescence and DsRed with red fluorescence). On the other hand, the rBDV-5′DsRed vector was unable to produce recombinant virus in infected cells.
- Example 5 In Example 1, using a firefly-derived luciferase gene (1.6 kb) (manufactured by Clontech) instead of the GFP gene, recombination in which the luciferase gene was inserted into the untranslated region between the P gene and the M gene A vector (rBDV-p / mLuci vector) was prepared, and a recombinant virus was prepared in the same manner as in Example 2. As a comparison, a recombinant vector (rBDV-5 ′ Luci vector) in which the luciferase gene was inserted into the 5 ′ end of the BDV genome using the luciferase gene instead of the GFP gene in Reference Example 1 was prepared.
- rBDV-5 ′ Luci vector a recombinant vector in which the luciferase gene was inserted into the 5 ′ end of the BDV genome using the luciferase gene instead of the GFP gene in Reference Example 1 was prepared.
- the cells were infected with the recombinant virus and the luciferase gene was expressed on the 10th day using the same antibody against N protein (anti-BDV N antibody) as in Example 2.
- N protein was observed in the cells infected with the recombinant virus produced from the rBDV-p / mLuci vector, as shown in FIG. 15a, but rBDV-5 ′ The Luci vector was unable to produce recombinant virus in infected cells.
- the luciferase activity in the recombinant virus rBDV-p / mLuci-infected Vero cells was measured using a luciferase assay kit (Promega) according to the attached instructions. It showed significantly higher luciferase activity compared to infected cells (FIG. 15b). This confirmed that the luciferase produced from the recombinant virus rBDV-p / mLuci was functioning.
- Example 6 In the same manner as in Example 3, it was produced from a plasmid in which GFP was inserted between the PM genes prepared in Example 1 (plasmid pCAG-Fct-P / M-GFP, hereinafter referred to as “p / mGFP”).
- N protein The indirect immunofluorescence antibody method using an antibody (anti-BDV N antibody) and a fluorescently labeled antibody (manufactured by Molecular Probes) and (2) GFP fluorescence were examined. As a result, it was found that the BDV virus was continuously expressed in infected cells (mouse cerebral cortex and cerebellum) for 2 to 8 months after inoculation.
- FIGS. 18a and 18b are fluorescence micrographs of brain cut surfaces of mice 8 months after inoculation with the recombinant virus.
- FIG. 18A is a macro photograph
- FIG. 18B is a photograph in which a portion surrounded by a square in FIG. 18A is enlarged by a microscope.
- GFP was detected by green fluorescence.
- the part that appears gray is the part that emits green fluorescence due to GFP.
- Example 7 Recovery of G-deficient virus (1) Plasmid construction A) Preparation of p / mGFP deltaG L linear (p / mGFP ⁇ G LL) Based on the p / mGFP prepared in Example 1, the G gene which is a viral membrane glycoprotein was deleted by introducing point mutation using PCR. . As a specific method, sequences (genome numbers (namely, bases of SEQ ID NO: 1) 2236-2238 and 2248-2250) encoding two methionines present in the G gene were replaced with threonine (ATG ⁇ ACG). FIG.
- FIG. 19 shows an outline of a procedure for preparing p / mGFP ⁇ G, which is a plasmid encoding a G gene-deficient virus.
- PCR was performed using primers A1 and B1 with the sequences shown in Table 1 and primers C1 and D1 (98 ° C for 10 seconds, 55 ° C for 5 seconds, 72 ° C for 0.5 or 1 minute for 25 cycles). (FIG. 19A).
- PCR (98 ° C 10 seconds, 55 ° C 5 seconds, 72 ° C 1.5 minutes 25 cycles) was performed again using both amplification products (1stPCR product) as a template and the primers A1 and D1 (Fig. 19).
- amplification product (2nd PCR product)
- the methionine of the G gene is mutated to threonine, and this is recombined with the vector p / mGFP using the restriction enzymes Bst1107I and NheI (FIG. 19 (c)).
- / mGFP ⁇ G was obtained.
- the L gene intron region that was no longer needed was removed and the L gene was directly linked (L linearize). Specifically, from the restriction enzyme site Bst1107I (2166 to 2171st nucleotide sequence of SEQ ID NO: 1) to the first half exon of the L gene and the second half exon of the L gene (NheI site (6158 to 6163rd of SEQ ID NO: 1) Each of the base sequence) was amplified, combined, and incorporated into p / mGFPm ⁇ G. An outline of this procedure is shown in FIG.
- PCR (98 ° C 10 seconds, 55 ° C 5 seconds, 72 ° C 0.5 minutes 25 cycles) was performed using primers A1 and E1 and primers F1 and D1 shown in Table 1 and p / mGFP / ⁇ G as a template. (FIG. 20 (a)).
- PCR (98 ° C., 10 seconds, 55 ° C., 5 seconds, 72 ° C., 1 cycle, 25 cycles) was performed using both amplification products (1st PCR product) as templates and primers A1 and D1 (FIG. 20B).
- B) BDV G gene expression plasmid In order to recover the G-deficient virus, a plasmid for expressing the BDV G protein in mammalian cells was prepared as a helper plasmid. An outline of this procedure is shown in FIG. As a specific method, the G gene region was amplified by PCR using p / mGFP as a template, and inserted downstream of the chicken beta actin promoter (the same method as the above-described helper plasmids of other N, P, and L genes).
- PCR was performed using primers G1 and H1 shown in Table 1, and primers I1 and J1 and p / mGFP as a template (98 ° C for 10 seconds, 55 ° C for 5 seconds, 72 ° C for 0.5 or 1.0 minutes for 25 cycles). (FIG. 21 (a)).
- PCR (98 ° C 10 seconds, 55 ° C 5 seconds, 72 ° C 1.5 minutes 25 cycles) was performed using both amplification products (1st PCR product) as a template and primers G1 and J1 (Fig. 21 (b)). .
- the 2409-2415th GGTTATG of the wild-type BDV (WT) genome is defined as agtctcc ( ⁇ SA)
- the 2437-2442nd GGTTATG of the wild-type BDV (WT) genome is defined as agtctcc ( ⁇ SD).
- This 2nd PCR product ( ⁇ SDSA G gene) was inserted into an expression plasmid (pCXN2 used in the preparation of the helper plasmid of Example 1) using restriction enzymes KpnI and SmaI (FIG. 21 (c)), and BDV G gene expression plasmid was made.
- the nucleotide sequence of the recombinant plasmid was confirmed by DNA sequencing.
- pCXN2 was used to prepare a G gene expression plasmid, but other plasmids capable of expressing a gene in mammalian cells can also be used.
- the primer sequences used above are shown in Table 1.
- BDV G gene stable expression cells were prepared using the G protein expression plasmid prepared in (1) A) above.
- 1-5 ⁇ 10 5 mammalian cultured cell lines used for recovery that is, 293T cells and Vero cells, were seeded in a 9.4 cm 2 culture dish, and the next day a commercially available gene transfer reagent (Fugen6, Lipofectamine2000) was used.
- Fugen6, Lipofectamine2000 was used.
- 2 to 5 ⁇ g of the plasmid DNA prepared in (1) above was introduced. Cells were cultured at 37 ° C. using Dulbecco's modified Eagle MEM medium.
- G gene stable expression cell lines (G gene stable expression 293T cells and G gene stable expression Vero cells) were isolated by this method.
- 293T cells were cultured at 37 ° C. Three days after gene introduction, the cells were subcultured and co-cultured with the G gene stably expressing Vero cells prepared above, and then the Vero cells were recovered as G gene-deficient virus-infected Vero cells.
- Example 8 Preparation of p / mGFP ⁇ G LL-infected cells and pseudotype virus (1) Preparation of p / mGFP ⁇ G LL-infected cells and confirmation of persistent infectivity A) Preparation of p / mGFP ⁇ G LL-infected cells Vero cells were inoculated with the virus collected in Example 7 (3) B) or C) to prepare p / mGFP ⁇ G LL-infected cells.
- Opti-MEM (Invitrogen: GIBCO) was used for dilution of the virus solution, and 100 ⁇ l of virus-diluted Opti-MEM was inoculated into a single layer of Vero cells spread on a 24-well plate (about 0.1 to 0.01 virus per Vero cell). Particles) and sensitized for 1 hour at 37 ° C. Thereafter, the cells were washed with PBS- and cultured at 37 ° C. in Dulbecco's modified Eagle MEM medium. Infected cells inoculated did not propagate the virus, so 100% infected cells were isolated by the cell cloning method (limit dilution method). Judgment whether the cells were infected or not was made by observing the expression of GFP with a fluorescence microscope. The infected cells separated here were also used for the preparation of pseudotype virus described later.
- FIG. 22 shows the virus positive rate of each cell on the 12th day after co-culture with cells stably expressing G gene, using GFP as an index. From FIG. 22, when the number of GFP positive cells per 100,000 cells was 1 when p / mGFP ⁇ G was used, p / mGFP ⁇ G LL showed an approximately 8-fold positive rate. From this, it was found that p / mGFP ⁇ G LL has a higher ability to produce recombinant BDV than p / mGFP ⁇ G.
- B) or C) (G-deficient recombinant virus) Inoculated with virus: cells 1: 100 and observed for growth and persistence. The infection rate was measured by counting the number of infected cells per 100,000 cells plated on a 24-well plate. As a result, as shown in FIG. 23, when inoculated into Vero cells, the infection rate was about 1%, but when inoculated into Vero cells stably expressing G gene, the infection rate increased with progress.
- FIG. 24a shows the results of examining protein expression in cells infected with wild-type BDV and G-deficient recombinant virus by Western blotting.
- G, N, and GFP are G protein, N protein, and GFP, respectively.
- FIG. 24 b is a fluorescence micrograph of Vero cells infected with G-deficient recombinant virus. The part that appears gray in the photograph of FIG. 24b is the green fluorescent part due to GFP. 24a and b confirmed that GFP introduced by the virus was expressed in cells infected with the G gene-deficient virus.
- the amplification product has a DNA sequence encoding a chimeric membrane protein (hereinafter also referred to as a chimeric VSV-G protein) derived from BDV in the intracellular region and the extracellular and transmembrane regions derived from VSV.
- This PCR product was incorporated into pCXN2 (see (1) B) of Example 7) (Fig. 25 (b)) using restriction enzymes EcoRI and EcoRV to obtain a VSV-G expression plasmid.
- a plasmid expressing a chimeric membrane protein of BDV and RabV (chimeric Rab-G expression plasmid) was prepared using a G gene expression plasmid (GeneBank N ID: AB044824.1) of RabV: Nishigahara strain as a template and a primer as a primer. The procedure was the same as above except that primers C2 and D2 shown in Table 2 were used instead of A2 and B2, and KpnI and EcoRV were used as restriction enzymes.
- the Rab-G expression plasmid expresses a chimeric membrane protein derived from BDV in the intracellular region and RabV in the extracellular and transmembrane regions (hereinafter also referred to as chimeric Rab-G protein).
- VSV-G protein stable expression strain and Rab-G protein stable expression strain were prepared.
- Chimeric membrane protein stable expression cells were prepared using the plasmid prepared in (2) A) above or the plasmid introduced into the Tet system expression plasmid prepared in the same manner.
- the plasmid expressing the chimeric G protein prepared in (2) A) above or a Tet prepared in the same manner Using the plasmid introduced into the system expression plasmid, it was introduced into 293T cells and Vero cells, and p / mGFP ⁇ G LL-infected cells prepared in (1) above.
- the drug resistance concentration and the like of the Tet system were performed as described in the attached manual. The Invitrogen T-REx system was used this time.
- FIG. 26 shows the difference in virus recovery efficiency (particle formation efficiency) among the three when the G gene of BDV and the outer shell gene of VSV and Rab are used as the G gene.
- the virus recovery efficiency is expressed as a relative value with 1 when the BDV G gene is used.
- pseudotyped virus covered with VSV or Rab membrane protein was recovered using chimeric protein-expressing cells.
- pseudotype viruses are pseudotype viruses that have an outer shell derived from VSV or Rab and can express a recombinant BDV genome encoded by p / mGFP ⁇ G LL.
- Example 9 M and G gene-deficient virus (1) Plasmid p / mGFP ⁇ M-G LL in which the M gene was deleted based on p / mGFP ⁇ G LL was prepared.
- FIG. 27 shows an outline of the procedure for preparing the p / mGFP ⁇ M-G LL plasmid in which the M gene is deleted.
- PCR (98 ° C 10 seconds, 55 ° C 5 seconds, 72 ° C 1.5 minutes for 25 cycles) was performed using p / mGFP ⁇ G LL as a template and the primers A3 and B3 shown in Table 3. (FIG. 27 (a)).
- the obtained PCR product (1st PCR product) was inserted into p / mGFP ⁇ G LL using PacI and NheI to prepare p / mGFP ⁇ M-G LL (FIG. 27 (b)).
- FIG. 28 shows an outline of the procedure for producing the p / mGFP ⁇ M-GLL PM tandem vector.
- PCR 98 ° C for 10 seconds, 55 ° C for 5 seconds, 72 ° C for 0.5 minutes for 25 cycles
- FIG. 28 (a) Furthermore, PCR (98 ° C 10 seconds, 98 ° C 5 seconds, 72 ° C 0.5 minutes 25 cycles) was performed using the obtained PCR product (1stPCR product) as a template and primers C3 and E3 (Table 3) ( Figure 25). 28 (b)).
- the obtained PCR product (2nd PCR product) was inserted into p / mGFP ⁇ M-GLL using EcoT22I and BstBI.
- a new foreign gene insertion cassette Sse8381I-SwaI could be inserted into p / mGFP ⁇ M-GLL, and a p / mGFP ⁇ M-GLL PM tandem vector was obtained.
- This cassette can be incorporated into other p / m vectors having a BstBI-PacI site between the ORF of the P gene and the ORF of the M gene using EcoT22I and BstBI.
- p / m vectors for the treatment of Alzheimer's disease
- a ⁇ amyloid beta protein
- RNA was extracted from cultured cells derived from human, and reverse transcription of mRNA was performed with reverse transcriptase (Invitrogen, Superscript III) using oligoT as a primer.
- NEP was amplified by PCR (25 cycles of 98 ° C. for 10 seconds, 55 ° C. for 5 seconds, and 72 ° C. for 2.5 minutes) using the obtained cDNA as a template and primers A4 and B4 shown in Table 6.
- the obtained PCR product was recombined with a p / mGFP vector using BstBI-PacI to prepare a p / mNEP vector.
- the GFP cDNA was replaced with the NEP cDNA in the plasmid (p / mGFP) in which GFP was inserted between the BDV PM genes prepared in Example 1.
- a recombinant vector (hereinafter referred to as comparative vector 1) was prepared by inserting a mutation in the NEP enzyme active site into a p / m vector.
- PCR 98 ° C for 10 seconds, 55 ° C for 5 seconds, 72 ° C for 2 minutes or 0.5 minutes for 25 cycles
- primers A4 and C4 shown in Table 6, and B4 and D4 and p / mNEP as a template.
- PCR 98 ° C. for 10 seconds, 55 ° C. for 5 seconds, 72 ° C. for 2.5 minutes for 25 cycles
- Recombinant virus was recovered from each of the prepared p / mNEP vector and comparative vector 1 in the same manner as in Example 2, and the properties were analyzed. The recovered virus was administered to Alzheimer's disease model mice.
- NEP is a recombinant virus p / mNEP-infected cell produced from the p / mNEP vector
- dn is a comparative cell infected with the virus produced from the comparison vector 1
- nc is non-infected It is a cell.
- ⁇ -N is an N protein of BDV. From FIG. 29, it was confirmed that NEP was expressed in the cells infected with the recombinant virus produced from the p / mNEP vector and the comparative vector 1 (comparative cell 1).
- DAGNPG (Sigma), which artificially synthesizes the reaction region, was used for NEP activity measurement.
- cells infected with p / mNEP were detached from the culture dish with trypsin and collected by centrifugation.
- the collected cells were resuspended in a DAGNPG-containing solution (50 mM Tris-HCl, 1 ⁇ M captopril, 50 ⁇ M DAGNPG), and reacted at 37 ° C. for 2 hours.
- the enzyme was inactivated by heating at 100 ° C. for 5 minutes. Thereafter, the mixture was centrifuged at about 15000 g at 4 ° C. for 5 minutes, and the supernatant was collected.
- FIG. 30 shows the results of measuring the cleavage enzyme activity. In the p / mNEP-infected cells, the NEP activity was significantly higher than that in the non-infected cells and the comparative cells 1.
- Alzheimer's disease model mice were first inoculated with p / mNEP.
- B6SJL-Tg (APPSwFlLon, PSEN1 * M146L * L286V) 6799Vas / J (Jackson Research Institute No6554) and B6.Cg-Tg (APPSwe, PSEN1dE9) 85Dbo / J ( Jackson Laboratory No5864) was used. All of these model mice are expressed by expressing a human A ⁇ precursor protein and a mutant of its degrading enzyme presenilin in nerve cells, and have been reported to show Alzheimer's disease-like symptoms early in life.
- FIG. 31 shows an outline of the procedure for preparing pSIRIUS-B.
- introduction vectors necessary for introducing various miRNA sequences were prepared.
- BstBI and PacI restriction enzyme sites were introduced into the multicloning site of pBluescript SK- (FIG. 31 (b)) to complete the p / mmiR155 introduction vector pSIRIUS-B.
- FIG. 31 (a) The sequence of the DNA fragment schematically shown in FIG. 31 (a) and the restriction enzyme sites in the sequence are shown in Table 4 below.
- the miR155 target sequence (oligo) was introduced from pSirius-B miR-155 into a p / m vector using BstBI-PacI to produce p / m miR155 (FIG. 32 (b)).
- a plasmid in which the target sequence of miR155 was introduced downstream of the reporter gene luciferase was prepared so that the effect of miR155 could be determined.
- FIG. 33 shows the transcription inhibition efficiency of the target gene in the cells infected with the recombinant virus (wt in FIG. 33: BDV wild-type infected cells, x1: p / m miR155-infected cells).
- PCR was performed using the plasmid prepared in A) (with the target miRNA inserted) as a template using primers E4 and F4 shown in Table 6 (98 ° C for 10 seconds, 55 ° C for 5 seconds, 72 ° C for 0.5 minutes for 25 minutes). cycle).
- the obtained PCR product was inserted into pSIRIUS-D using SalI and XhoI (FIG. 34 (a)) (note the direction of insertion at this time). Further, the insert was excised from the prepared plasmid with SalI and XbaI (FIG.
- FIG. 34 (c) A schematic diagram of miRNA ⁇ 2 and miRNA ⁇ 4 p / m vectors is shown in FIG.
- the obtained miRNA ⁇ 2 and miRNA ⁇ 4 p / m vectors were recovered by the same method as shown in Example 2 and the effects were confirmed.
- the results are shown in FIG. In FIG. 33, x1, x2, and x4 are the numbers of miR155 inserted into the plasmid, respectively. As can be seen from FIG. 33, the greater the number of miR155 introduced, the more efficiently the target gene expression was inhibited.
- miR155 introduced into cells was confirmed to be expressed in cells continuously, and the vector of the present invention was shown to be useful as an RNA vector capable of expressing functional RNA.
- miRNA transfer vector A Effect of miRNA in mouse hippocampal primary cultured cells using p / m miRNA GAPDH
- miRNA (miR-GAPDH) against GAPDH constitutively expressed in the cell was inserted instead of miRNA155
- a plasmid (p / m miRNA-GAPDH) was prepared, and its effect was confirmed in mouse hippocampal primary culture cells closer to the living body.
- the production method of p / m miRNA-GAPDH is almost the same as the production method of p / m miR155 shown in (1) (the sequence of synthesized miR-GAPDH is shown in SEQ ID NOs: 40 and 41).
- the DNA of SEQ ID NO: 40 and the DNA of SEQ ID NO: 41 form a double strand in the plasmid.
- Recombinant virus p / m miRNA-GAPDH produced from p / m miRNA-GAPDH was recovered by the same method as shown in Example 2.
- the recovered recombinant virus p / mmiRNA-GAPDH was inoculated at an MOI of 0.01 to primary cultured cells collected from the hippocampus of newborn mice. After fixing 7 days later, the cells were stained with anti-BDV-N antibody and anti-GAPDH antibody, and observed with a fluorescence microscope.
- FIG. 36 shows that the expression of GAPDH was significantly suppressed in the cells infected with the recombinant virus p / mmiR-GAPDH compared to the cells infected with wild-type BDV (FIG. 36).
- 36a and b are cells infected with wild type BDV
- FIGS. 36c and d are cells infected with recombinant virus p / mmiR-GAPDH.
- 36a and c are fluorescence micrographs of cells stained with anti-BDV-N antibody
- FIGS. 36b and d are fluorescence micrographs of cells stained with anti-GAPDH antibody. The inside of the square of FIG.
- FIG. 36b and d is an enlarged photograph, and the arrow attached
- FIG. 36b the expression level of GAPDH is high in both uninfected cells and infected cells (GAPDH is not suppressed), but in FIG. 36d, it is observed that the expression level of GAPDH is suppressed in infected cells compared to non-infected cells. It was.
- p / m miRNA155 a plasmid in which miRNA (miRNA-APP) for APP, which is the causative protein of Alzheimer's disease, was inserted instead of miRNA155 (p / m miRNA-APP) was prepared and its effect was confirmed using p / m miRNA-APP-infected Vero cells.
- the production method of p / m miRNA-APP is almost the same as the production method of p / m miR155 shown in (1) (the synthesized miRNA-APP is shown in SEQ ID NOs: 42 and 43).
- the DNA of SEQ ID NO: 42 and the DNA of SEQ ID NO: 43 form a double strand in the plasmid.
- Recombinant virus p / m miRNA-APP produced from p / m miRNA-GAPDH was recovered by the same method as shown in Example 2.
- the APP expression plasmid (prepared according to the instructions attached to pcDNA3.
- a similar experiment was performed using cells infected with a recombinant virus produced from p / mGFP. As a result, the amount of APP mRNA was significantly reduced in the Vero cells infected with the recombinant virus p / mmiRNA-APP as compared to the Vero cells infected with p / mGFP (FIG. 37).
- the recombinant virus produced from the viral vector of the present invention can express a foreign gene non-cytotoxicly and efficiently in the cell nucleus, and since the viral genome is RNA, it is inserted into the host chromosome. It is a safe vector.
- the viral vector of the present invention utilizes Borna disease virus, since Borna disease virus has an infection-directed property to nerve cells, it can be used to selectively introduce foreign genes into the brain nervous system. It is an excellent vector. Therefore, the present invention is useful because it can be used as a gene transfer technique that does not affect the host chromosome in various fields, for example, treatment and prevention of cranial nerve disease, visualization technique of nervous system cells in the brain neurochemistry region, etc. It is.
- the present invention can also be applied to stable expression vector technology for functional RNA such as siRNA, miRNA, RNA aptamer. Therefore, the present invention is useful in the fields of medicine, animal medicine, clinical trials, research and the like.
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Abstract
Description
項1. (a)ボルナ病ウイルスゲノムにおける少なくともN遺伝子、X遺伝子、P遺伝子及びL遺伝子を、ボルナ病ウイルスゲノムにおける順序と同じ順序で有し、前記P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNA、(b)リボザイムをコードするDNA及び(c)プロモーター配列を含み、該(a)の上流及び下流に(b)が配置され、かつ(a)及び(b)が(c)の下流に配置されていることを特徴とするウイルスベクター。
項2. (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムにおいてG遺伝子が破壊された配列を有し、かつP遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNAである項1に記載のウイルスベクター。
項3. (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムにおいてG遺伝子及びM遺伝子が破壊された配列を有し、かつP遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNAである項1又は2に記載のウイルスベクター。
項4. (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムをコードするcDNAのP遺伝子の翻訳領域とM遺伝子の翻訳領域との間の非翻訳領域に外来性遺伝子を挿入した組換えウイルスのcDNAである項1に記載のウイルスベクター
項5. (c)プロモーター配列が、RNAポリメラーゼII系のプロモーター配列であることを特徴とする項1~4のいずれかに記載のウイルスベクター。
項6. (a)組換えウイルスRNAのcDNAの上流に(b1)ハンマーヘッドリボザイムをコードするcDNAが配置され、かつ、該(a)の下流に(b2)δ型肝炎ウイルスリボザイムをコードするcDNA配列が配置されていることを特徴とする項1~5のいずれかに記載のウイルスベクター。
項8. 項1~6のいずれかに記載のウイルスベクターと共に、ヘルパープラスミドとしてボルナ病ウイルスのN遺伝子、P遺伝子及びL遺伝子を発現するプラスミド又はプラスミド群をin vitroの細胞に導入する工程、及び該ウイルスベクター及びヘルパープラスミドを導入した細胞を培養して組換えウイルスを産生させる工程を含むことを特徴とする組換えウイルスの作製方法。
項9. ヘルパープラスミドとして、さらに、ウイルスの外殻遺伝子を発現するプラスミドをin vitroの細胞に導入する項8に記載の組換えウイルスの作製方法。
項10. ヘルパープラスミドとして、さらに、ボルナ病ウイルスのM遺伝子を発現するプラスミドをin vitroの細胞に導入する項8又は9に記載の組換えウイルスの作製方法。
項12. 項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルスを含有することを特徴とする外来性遺伝子導入剤。
項13. 項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルスを含有することを特徴とする脳神経系細胞への外来性遺伝子導入剤。
項14. 項1~6のいずれかに記載のウイルスベクターを含有することを特徴とする外来性遺伝子導入用キット。
項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルスを動物に投与する脳神経系細胞への外来性遺伝子の導入方法、
項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルスの、外来性遺伝子導入剤製造のための使用。
項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルスの、脳神経系細胞への外来性遺伝子導入剤製造のための使用。
in vitroの細胞又は動物に外来性遺伝子を導入するための、項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルス。
脳神経系細胞に外来性遺伝子を導入するための、項7に記載の組換えウイルス、又は項8~10のいずれかに記載の方法により作製された組換えウイルス。
1.ウイルスベクター
本発明のウイルスベクターは、(a)ボルナ病ウイルスゲノムにおける少なくともN遺伝子、X遺伝子、P遺伝子及びL遺伝子を、ボルナ病ウイルスゲノムにおける順序と同じ順序で有し、前記P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNA、(b)リボザイムをコードするDNA及び(c)プロモーター配列を含み、該(a)の上流及び下流に(b)が配置され、かつ(a)及び(b)が(c)の下流に配置されているものである。
以下、上記(a)の組換えウイルスRNAのcDNAを、単に「(a)組換えBDVゲノムのcDNA」ともいう。本発明のウイルスベクターは、本発明の効果を奏する限り、上記(a)、(b)及び(c)以外の配列を含んでもよい。
本発明における(a)組換えBDVゲノムのcDNAは、BDVゲノムにおける少なくともN遺伝子、X遺伝子、P遺伝子及びL遺伝子を、ボルナ病ウイルスゲノムにおける順序と同じ順序で有する組換えBDV RNAのcDNAであり、該組換えBDV RNAは、前記P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する。
このような(a)組換えBDVゲノムのcDNAとして、BDVゲノム又はBDVゲノムにおいてG遺伝子及びM遺伝子のいずれか又は両方が破壊された配列において、P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列をコードするcDNA等が好適に用いられる。
中でも、本発明における(a)組換えBDVゲノムのcDNAとして、BDVゲノムにおいてG遺伝子及びM遺伝子のいずれか又は両方が破壊された配列を有し、P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有するRNAのcDNAが好適である。
遺伝子を破壊するとは、通常、該遺伝子が蛋白質(例えばG遺伝子であればG蛋白質)をコードすることができる形態で存在しないことを意味する。遺伝子の破壊は、その遺伝子全体を削除することの他、該遺伝子の一部の削除、該遺伝子に他の配列を挿入する、該遺伝子中のアミノ酸を他のアミノ酸で置換する等により行うことができる。
He80;GenBank Accession# L27077, Cubitt,B., Oldstone,C. and de la Torre,J.C. Sequence and genome organization of Borna disease virus. J. Virol. 68 (3), 1382-1396 (1994).
H1766;GenBank Accession# AJ311523, Pleschka,S., Staeheli,P., Kolodziejek,J., Richt,J.A., Nowotny,N. and Schwemmle,M. Conservation of coding potential and terminal sequences in four different isolates of Borna disease virus. J. Gen. Virol. 82 (PT 11), 2681-2690 (2001).
Strain V;GenBank Accession# U04608, Briese,T., Schneemann,A., Lewis,A.J.,
Park,Y.S., Kim,S., Ludwig,H. and Lipkin,W.I. Genomic organization of Borna disease virus. Proc. Natl. Acad. Sci. U.S.A. 91 (10), 4362-4366 (1994).
huP2br;GenBank Accession# AB258389, Nakamura, Y., Takahashi, H., Shoya, Y., Nakaya, T., Watanabe, M., Tomonaga, K., Iwahashi, K., Ameno, K., Momiyama, N., Taniyama, H., Sata, T., Kurata, T., de la Torre, J. C., Ikuta, K. Isolation of Borna disease virus from human brain tissue, J. Virol 74 (2000) 4601-4611.
No/98;GenBank Accession# AJ311524, Nowotny,N. and Kolodziejek,J. Isolation and characterization of a new subtype of Borna disease virus. J. Gen. Virol. 74, 5655-5658 (2000).
Bo/04w;GenBank Accession# AB246670, Watanabe,Y., Ibrahim,M.S., Hagiwara,K., Okamoto,M., Kamitani,W., Yanai,H., Ohtaki,N., Hayashi,Y., Taniyama,H., Ikuta,K. and Tomonaga,K. Characterization of a Borna disease virus field isolate which shows efficient viral propagation and transmissibility. Microbes and Infection 9 (2007) 417-427.
リボザイムとしては、(a)組換えウイルスのcDNAから転写された任意の外来性遺伝子を切断することができる配列のものであればよい。(b)としては、例えば、ハンマーヘッドリボザイム(HamRz)、δ型肝炎ウイルスリボザイム(HDVRz)、ヘアピンリボザイム、人工リボザイム等のリボザイムをコードするcDNA等のDNAが挙げられる。また、リボザイム活性を有する限り、上記リボザイムの改変型リボザイムをコードするcDNA等のDNAも使用することができる。改変型リボザイムとしては、共通配列を有し、1~数個(数個とは、例えば、10個、好ましくは5個、より好ましくは3個、さらに好ましくは2個である)の塩基が置換、欠損又は付加された塩基配列からなり、かつリボザイムとして機能するポリヌクレオチド等が挙げられる。中でも、本発明におけるリボザイムとしては、ハンマーヘッドリボザイム(HamRz)、δ型肝炎ウイルスリボザイム(HDVRz)が好ましい。また、(a)組換えBDVゲノムのcDNAの上流、すなわち3’末端側に(b1)HamRzをコードするDNA(好ましくはcDNA)が配置され、かつ、該(a)の下流、すなわち5’末端側に(b2)HDVRzをコードするDNA(好ましくはcDNA)配列が配置されていることが特に好ましい。これにより、細胞における外来性遺伝子の発現効率が向上する。
HDVRzの塩基配列は、Ferre-D'Amare,A.R., Zhou,K. and Doudna,J.A. Crystal structure of a hepatitis delta virus ribozyme. Nature 395 (6702), 567-574 (1998)
等に記載されている。本発明においては、これらの文献に記載されているHamRzの塩基配列をコードするcDNAを用いることができる。本発明における特に好ましいHamRz及びHDVRzの塩基配列を、以下に示す。
HamRz:
5’-UUGUAGCCGUCUGAUGAGUCCGUGAGGACGAAACUAUAGGAAAGGAAUUCCUAUAGUCAGCGCUACAACAAA-3’(配列番号2)
HDVRz:
5’-GGCCGGCAUGGUCCCAGCCUCCUCGCUGGCGCCGGCUGGGCAACACCAUUGCACUCCGGUGGCGAAUGGGAC-3’
(配列番号3)
本発明における(c)プロモーター配列としては、RNAポリメラーゼII系のプロモーター配列、RNAポリメラーゼI系プロモーター配列、T7ポリメラーゼ系プロモーター配列が挙げられるが、中でもRNAポリメラーゼII系のプロモーター配列が好ましい。RNAポリメラーゼII系のプロモーターとしては、CMVプロモーター、CAGGSプロモーターが挙げられる。中でも、CAGGSプロモーターが特に好ましい。このようなプロモーター配列は、例えば、J.A. Sawicki, R.J. Morris, B. Monks, K. Sakai, J. Miyazaki, A composite CMV-IE enhancer/b-actin promoter is ubiquitously expressed in mouse cutaneous epithelium, Exp. Cell Res. 244 (1998) 367-369に記載されている。
本発明のウイルスベクターは、SV40ウイルス複製開始点/プロモーター領域配列の1部又は全部の配列を含むことができる。また、ウイルスベクターがSV40ウイルス複製開始点/プロモーター領域配列の1部又は全部の配列を含む場合には、該配列は(a)及び(b)の下流に配置されていることが好ましい。SV40ウイルスDNAの複製開始点/プロモーター領域配列の一部としては、SV40複製開始点/プロモーター領域内の5’側の113塩基からなる断片が好適である。
SV40ウイルス複製開始点/プロモーター領域配列(配列番号4)は、例えば、D.A. Dean, B.S. Dean, S. Muller, L.C. Smith, Sequence requirements for plasmid nuclear import, Exp. Cell. Res. 253 (1999) 713-722等に記載されている。
本発明のウイルスベクターの作製方法としては特に限定されず、自体公知の遺伝子工学的手法を用いればよい。例えば、Yanai et al., Microbes and Infection 8 (2006), 1522-1529の“Materials and methods”の2.2 Plasmid constructionに記載されている方法において、CAT遺伝子をBDVのゲノム配列に置き換え、さらにP遺伝子の下流に連結する非翻訳領域(P遺伝子とM遺伝子との間の非翻訳領域)内に目的とする外来性遺伝子を挿入することによって、本発明の自己複製型(持続感染型)のウイルスベクターを作製することができる。上記方法により作製されるウイルスベクターは、(a)組換えウイルスRNAのcDNAとして、BDVゲノムをコードするcDNAのP遺伝子の翻訳領域とM遺伝子の翻訳領域との間の非翻訳領域に外来性遺伝子を挿入した組換えウイルスのcDNA(例えば、図3に模式的に示される構造を有する組換えウイルスのcDNA)を有するものである。
上記ウイルスベクターにコードされるRNAを含む組換えウイルスも、本発明の1つである。好ましくは、ウイルスベクターにコードされるRNA、並びにBDVのN蛋白質、BDVのP蛋白質及びBDVのL蛋白質を含む組換えウイルスである。本発明の組換えウイルスは、上記組換えBDVゲノムを含むことにより、細胞に感染後、持続的に外来性遺伝子を発現することができる持続感染型の組換えウイルスである。組換えウイルスは、所望によりBDVのG蛋白質又は他のウイルスの外殻蛋白質を有していてもよく、さらに、BDVのM蛋白質を有していてもよい。本発明における外殻遺伝子は、ウイルスの外殻蛋白質をコードする遺伝子である。BDVでは、外殻蛋白質をコードする遺伝子は、G遺伝子である。
(1)BDVのN遺伝子を発現するプラスミド、BDVのP遺伝子を発現するプラスミド及びBDVのL遺伝子を発現するプラスミド
(2)BDVのN遺伝子及びP遺伝子を発現するプラスミド、並びにBDVのL遺伝子を発現するプラスミド
(3)BDVのN遺伝子及びL遺伝子を発現するプラスミド、並びにBDVのP遺伝子を発現するプラスミド
(4)BDVのN遺伝子、L遺伝子及びP遺伝子を発現するプラスミド
BDV以外のウイルスの細胞外配列及び細胞膜貫通配列をコードする外殻遺伝子をヘルパープラスミドに用いると、遺伝子が由来するウイルスの種類により、産生されるウイルスの細胞指向性を変化させることができる。例えば、上皮系、呼吸器系細胞等に組換えウイルスを感染させる場合には、上皮系、呼吸器系細胞等への指向性が高いウイルス(例えば麻疹ウイルス、センダイウイルス、水疱性口内炎ウイルス等)の外殻蛋白質の細胞外配列及び細胞膜貫通配列をコードし、かつBDVのG蛋白質の細胞内配列をコードする、外殻遺伝子を発現するヘルパープラスミドを用いることが好ましい。
例えば、組換えウイルスであることは、感染した細胞内での外来性遺伝子(例えばGFPなど)の発現を定量解析することで確認できる。産生されたウイルスが持続性感染型であることは、感染した細胞内での外来性遺伝子(例えばGFPなど)の発現を定量解析すると共に、その培養上清中に次の世代の組換えウイルスの粒子が産生されることを調べることにより確認される。培養上清中に次の世代の組換えウイルスの粒子が産生されることは、例えば、その上清を遠心分離などにより回収し、これをさらに他の細胞へ感染させ、該細胞において組換えウイルスに由来する外来性遺伝子が発現することを調べることで確認できる。
生体細胞(動物個体中の細胞)に組換えウイルスを感染させる場合には、この組換えウイルスを含む上清を、超遠心機を用いて濃度勾配による超遠心を行なうことによりウイルス粒子へと高度の精製を行うことが好ましい。精製を行ったウイルス粒子を、例えばリン酸緩衝生理食塩水に浮遊させ、希釈を行った後に適量を動物へ感染させる。
上記組換えウイルスを細胞に感染させることにより、該ウイルスに組み込まれた外来性遺伝子を細胞や生体に導入することができる。このような、上記組換えウイルス、又は上記方法により作製された組換えウイルスをin vitroの細胞又は動物に感染させる工程を含む外来性遺伝子の導入方法も本発明の1つである。
組換えウイルスの接種量としては、上記濃度の組換えウイルスを含む希釈液を、鼻腔内接種では1回につき通常約5μL~1mL、脳内接種では1回につき通常約1~50μL接種する。組換えウイルスの動物への接種量は、動物の体重等に応じて適宜選択すればよく、例えば、上記濃度の組換えウイルスを含む希釈液をマウス又はラットに鼻腔内接種する場合には、1回につき通常約5~200μL、好ましくは約10~100μL接種する。
組換えウイルスの接種量としては、接種部位等により適宜選択すればよく、特に限定されない。例えば、通常、組換えウイルスを含む希釈液のウイルス力価を約10-1~109FFUとして、この組換えウイルスを含む希釈液を、マウスであれば1回につき通常約5~500μL、好ましくは約20~200μL接種する。
(1)上記ウイルスベクター、又は、(2)上記組換えウイルス、又は上記方法により作製された組換えウイルスを含有する外来性遺伝子導入剤も、本発明の1つである。好ましい態様としては、上記組換えウイルス、又は上記方法により作製された組換えウイルスを含有する外来性遺伝子導入剤である。このような外来性遺伝子導入剤は、上述した外来性遺伝子の導入方法において、組換えウイルスをin vitroの細胞又は生体細胞(動物)に感染させる際に好適に用いることができるものである。本発明は、動物の神経系細胞等に外来性遺伝子を導入するのに好適に用いることができる。中でも、脳神経系細胞に外来性遺伝子を導入するのにより好適に用いられる。
本発明のウイルスベクター、組換えウイルス及び外来性遺伝子の導入方法、並びに外来性遺伝子導入剤は、宿主染色体に影響を及ぼさない遺伝子導入技術として種々の分野に応用することができるものである。
例えば、本発明のウイルスベクター及び組換えウイルスは、ヒトを含む動物の脳神経系疾患治療のための遺伝子デリバリーベクターとして使用することができる。また、慢性肝疾患、腫瘍、感染症等に対するワクチン等にも好適に使用することができる。
脳神経系疾患としては、例えば、アルツハイマー病、パーキンソン病、多発性硬化症、統合失調症、自閉症、その他の機能性精神疾患等が挙げられる。本発明の組換えウイルスは、このような疾患の治療又は予防に有用である。例えば、本発明のウイルスベクターにおける外来性遺伝子として、脳神経系疾患の原因となる蛋白質を分解する酵素の遺伝子、該蛋白質の発現を抑制する機能を有する核酸配列等を使用すると、該ウイルスベクターから産生される組換えウイルスを脳神経細胞に感染させることにより、該原因蛋白質を分解又は該原因蛋白質の発現を抑制して該疾患を予防又は治療することができる。また、脳内物質(例えば、セロトニン、ドーパミン、ソマトスタチン、ネプリライシン等)の分泌低下により発症する疾患においては、該脳内物質をコードする遺伝子をウイルスベクターに挿入し、該ウイルスベクターから産生される組換えウイルスを脳神経細胞に感染させることにより、該脳内物質が産生されるため、該疾患を予防又は治療することができる。
なお、「治療」とは、病態を完全に治癒させることの他、完全に治癒しなくても症状の進展及び/又は悪化を抑制し、病態の進行をとどめること、又は病態の一部若しくは全部を改善して治癒の方向へ導くことを、「予防」とは病態の発症を防ぐこと、抑制すること又は遅延させることを、それぞれ意味するものとする。
本発明のキットは、ウイルスベクター以外に、ヘルパープラスミド、外来性遺伝子を導入する細胞、緩衝液、培地等を適宜含んでもよい。ウイルスベクターの好ましい態様は、上述した通りである。外来性遺伝子を導入する細胞は、脳神経系細胞等の神経系細胞等が好ましい。本発明のキットは、これまで技術的に困難であった脳神経系細胞等への外来性遺伝子の導入に好適に用いることができるものである。
1.プラスミドpCAG-Fctの作製
Yanai et al., Microbes and Infection 8 (2006), 1522-1529に記載されているプラスミドpCAG-HR-SV3を基に、その中に挿入されているクロラムフェニコールアセチルトランスフェラーゼ(CAT)遺伝子の領域をボルナ病ウイルスのHe/80株のゲノムの配列(配列番号1)に置き換えたプラスミドを以下のようにして作製した。
P遺伝子とM遺伝子の間の非翻訳領域に外来遺伝子挿入カセットを挿入し、プラスミドpCAG-Fct-P/Mを作製した。
A)実施例1で作製したpCAG-Fct(ボルナウイルスのHe80株のcDNA(配列番号1)がクローニングされているプラスミド)を鋳型に、EcoT22IからBst1107Iサイトまでの領域をプライマー1及び4、並びにプライマー2及び3を用いてそれぞれPCRで増幅した。その後、両方のPCR産物を0.5μLずつ混合し、プライマー1及び2にて再度増幅し、P-M遺伝子間にBstBIサイト及びPacIサイトを有する外来遺伝子挿入カセットを作製した。
B)A)のPCR産物をEcoT22I及びBst1107Iを用いてpCAG-Fctへと組込み、pCAG-Fct-P/Mを完成させた。
C)BstBIとPacIを用いてGFPを挿入し、プラスミドpCAG-Fct-P/M-GFPを完成させた。
(プライマー)
プライマー1:5-GGAATGCATTGACCCAACCGGTAGACCAGC-3(配列番号5)
プライマー2:5-AACATGTATTTCCTAATCGGGTCCTTGTATACGG-3(配列番号6)
プライマー3:5-ttcgaaGGTTGGttaattaaccataaaaaaatcgaatcacc-3(配列番号7)
プライマー4:5-ttaattaaCCAACCttcgaaGGTGATTCGATTTTTTTATGG-3(配列番号8)
ヘルパープラスミド、すなわちBDVのN遺伝子発現プラスミド(pcN)、BDVのP遺伝子発現プラスミド(pCXN2-P)及びBDVのL遺伝子発現プラスミド(pcL)を以下の手順で作製した。
pcNは、pHA-p40Nプラスミド(Kobayashi T, Watanabe M, Kamitani W, Zhang G, Tomonaga K and Ikuta K. Borna disease virus nucleoprotein requires both nuclear localization and export activities for viral nucleocytoplasmic shuttling. J. Virol. 75:3404-3412. (2001)からN遺伝子領域をPCRで増幅し、pBS-CAG(上述)へと挿入することで作製した。
プラスミドpCXN2-Pは、pcD-P(Zhang G, Kobayashi T, Kamitani W, Komoto S, Yamashita M, Baba S, Yanai H, Ikuta K and Tomonaga K. Borna disease virus phosphoprotein represses p53-mediated transcriptional activity by interference with HMGB1. J. Virol. 77:12243-12251. (2003))からゲル抽出した断片をpCXN2(Niwa H, Yamamura K, Miyazaki J 1991 Efficient selection for high-expression transfectants with a novel eukaryotic vector. Gene 108:193-199)のEcoRI及びXhoIサイトに挿入することによって作製した。
pcLについては、Perez et al., J. Gen. Virol. 84 (2003) 3099-3104に記載されている方法で作製した。組換えプラスミドのヌクレオチド配列は、DNAシークエンスによって確認した。
U. Schneider et al., Journal of Virology (2007) p.7293-7296に記載の方法に従って、BDVゲノムの5’末端側の非翻訳領域にGFP遺伝子を挿入した組換えウイルスベクターを作製した。この組換えウイルスベクター(rBDV-5’GFP)の構造を、図4に模式的に示す。
P-M遺伝子間プラスミドを用いたBDVベクターの作製と性状比較
pCAG-Fct-P/M-GFP及びヘルパープラスミド(N遺伝子発現プラスミド、P遺伝子発現プラスミド及びL遺伝子発現プラスミド;それぞれpcN、pCXN2-P及びpcL)を、FuGENE 6 transfection reagent (Roche Molecular Diagnostics(登録商標)、Pleasanton、CA)又Lipofectamine(登録商標)2000、Invitrogen)を用いて293T細胞に導入した。導入に使用したウイルスベクター等の量としては、104~106の細胞(293T細胞)に対して、pCAG-Fct-P/M-GFPを1~4μg使用し、pcN(0.125~0.5μg)、pCXN2-P(0.0125~0.05μg)、pcL(0.125~0.5μg)の割合でヘルパープラスミドを加えた。
抗BDV N抗体及び抗BDV M抗体を、Watanabe M, Zhong Q, Kobayashi T, Kamitani W, Tomonaga K, Ikuta K. Molecular ratio between Borna disease viral-p40 and -p24 proteins in infected cells determined by quantitative antigen capture ELISA. Microbiol Immunol. 2000. 44:765-72、Chase G, Mayer D, Hildebrand A, Frank R, Hayashi Y, Tomonaga K, Schwemmle M. Borna disease virus matrix protein is an integral component of the viral ribonucleoprotein complex that does not interfere with polymerase activity. J Virol. 2007. 81:743-749に記載の方法に従って作製した。
野生型BDV並びに各組換えウイルスをそれぞれ感染させたVero細胞を、感染後の一定の日数培養した後回収し、ガラスプレートに固定した後、これと、抗BDV N抗体(リン酸緩衝液で、抗BDV N抗体濃度0.2~5μg/mLに希釈したもの)又は抗BDV M抗体(リン酸緩衝液で、抗BDV M抗体濃度0.2~5μg/mLに希釈したもの)を37℃で1時間程度反応させた。洗浄後、2次抗体として蛍光標識された抗IgG抗体(モリキュラープローブ社製、リン酸緩衝液で、抗体濃度0.01~0.1μg/mLに希釈したもの)と同様に反応させた後に、細胞の蛍光(抗N抗体又はM抗体:赤、GFP:緑)を蛍光顕微鏡で観察した。
ノーザンブロット法及びウェスタンブロット法は、Watanabe Y, Ibrahim MS, Hagiwara K, Okamoto M, Kamitani W, Yanai H, Ohtaki N, Hayashi Y, Taniyama H, Ikuta K, Tomonaga K. Characterization of a Borna disease virus field isolate which shows efficient viral propagation and transmissibility. Microbes Infect. 2007. 9:417-427.に記載の方法に従って行った。
図6(a)は、感染後19日後のVero細胞におけるBDVのN遺伝子(上の図)及びGFP遺伝子(中の図)の発現量をノーザンブロットによって調べた結果を示す図である。図6(a)より、ウイルス蛋白質(N蛋白質)の遺伝子は、いずれのBDVを感染させた細胞においても同程度に発現していることが分かる。一方、組換えウイルスp/mGFPを感染させた細胞における、感染したウイルスに対する外来性遺伝子(GFP遺伝子)の発現率は、GFP遺伝子/N遺伝子=0.78であり、組換えウイルス5’GFPを感染させた細胞においては、GFP遺伝子/N遺伝子=0.45であった。感染したウイルスに対するGFP遺伝子の発現率は、組換えウイルスp/mGFPにおいて組換えウイルス5’GFPと比較して約2倍も多いことが分かる。図6(a)の下図は、解析に使用したRNA量を定量するために、サンプル中に含まれるリボゾームRNAを電気泳動後、可視化したものである。
図7a~fより、いずれのBDVウイルスを感染させた細胞でもN蛋白質は同程度発現していることから、ウイルスの複製能力は同程度であることがわかる。しかし、GFPの蛍光強度は、組換えウイルス5’GFPよりも組換えウイルスp/mGFPを感染させた細胞で顕著に大きいことから、組換えウイルスp/mGFPは、外来性遺伝子(GFP)の発現効率が組換えウイルス5’GFPより顕著に高いことが分かる。
図8a~fより、いずれのBDVウイルスを感染させた細胞でもM蛋白質は同程度発現していることから、ウイルスの複製能力は同程度であることがわかる。しかし、GFPの蛍光強度は、組換えウイルス5’GFPよりも組換えウイルスp/mGFPを感染させた細胞で顕著に大きいことから、組換えウイルスp/mGFPは、外来性遺伝子の発現効率が組換えウイルス5’GFPより顕著に高いことが分かる。
実施例2で作製した組換えウイルスp/mGFP及び参考例1で作製した組換えウイルス5’GFPをそれぞれ、ラットの脳へ感染させた。
精製された各組換えウイルスを、PBS又は培養メディウムで103FFUに希釈後、生後24時間以内の新生仔ラットの頭蓋内に、左側頭部より10~20μL接種した(図9)。接種後、7、14及び21日後に採材を行って、図10に示すように脳を各領域に分割し、各領域についてDNAを抽出し(キアゲン社のDNA抽出キットを用いた)、個別に組換えウイルスの感染をPCRとGFPの発現によりチェックした。PCRは、BDVに特異的なプライマーを用いた。これらのプライマーの配列を以下に示す。
BDV特異的なFowardプライマーの配列;
5- GGAATGCATTGACCCAACCGGTAGACCAGC -3 (配列番号9)
BDV特異的なReverseプライマー配列;
5- AACATGTATTTCCTAATCGGGTCCTTGTATACGG -3 (配列番号10)
実施例1において、GFP遺伝子の代わりにDsRed遺伝子(クローンテック社製)を用いて、P遺伝子とM遺伝子との間の非翻訳領域にDsRed遺伝子を挿入した組換えベクター(rBDV-p/mDsRedベクター)を作製し、実施例2と同様にして組換えウイルスを作製した。比較として、参考例1においてGFP遺伝子の代わりにDsRed遺伝子を用いて、BDVゲノムの5’末端にDsRed遺伝子を挿入した組換えベクター(rBDV-5’DsRedベクター)を作製し、実施例2と同様にして組換えウイルスを作製した。培養細胞に各組換えウイルスをそれぞれ感染させた後、10日目における細胞への組換えウイルスの感染及びDsRed遺伝子の発現を、実施例2と同様のN蛋白質に対する抗体(抗BDV N抗体)及び蛍光標識抗体(モリキュラープローブ社製)を使用する間接免疫蛍光抗体法により調べたところ、rBDV-p/mDsRedベクターから産生された組換えウイルスを感染させた細胞においては、図14に示すようにN蛋白質の発現(図14(a))及びDsRedの発現(図14(b))が観察された(N蛋白質は二次抗体によって緑色の蛍光及びDsRedは赤色の蛍光によって検出された)。一方、rBDV-5’DsRedベクターは、感染細胞において組換えウイルスを産生することができなかった。
実施例1において、GFP遺伝子の代わりにホタル由来のルシフェラーゼ遺伝子(1.6kb)(クローンテック社製)を用いて、P遺伝子とM遺伝子との間の非翻訳領域にルシフェラーゼ遺伝子を挿入した組換えベクター(rBDV-p/mLuciベクター)を作製し、実施例2と同様にして組換えウイルスを作製した。比較として、参考例1においてGFP遺伝子の代わりにルシフェラーゼ遺伝子を用いて、BDVゲノムの5’末端にルシフェラーゼ遺伝子を挿入した組換えベクター(rBDV-5’Luciベクター)を作製した。培養細胞に各組換えウイルスをそれぞれ感染させた後、10日目における細胞への組換えウイルスの感染及びルシフェラーゼ遺伝子の発現を、実施例2と同様のN蛋白質に対する抗体(抗BDV N抗体)を用いる間接免疫蛍光抗体法により調べたところ、rBDV-p/mLuciベクターから産生された組換えウイルスを感染させた細胞においては、図15aに示すようにN蛋白質が観察されたが、rBDV-5’Luciベクターは、感染細胞において組換えウイルスを産生することができなかった。また、組換えウイルスrBDV-p/mLuci感染Vero細胞(図15b中、rBDV・p/mLuci)におけるルシフェラーゼの活性をルシフェラーゼアッセイキット(Promega社)を用いて、添付の説明書に従って測定したところ、非感染細胞に比べ有為に高いルシフェラーゼ活性を示した(図15b)。このことから、組換えウイルスrBDV-p/mLuciから産生されるルシフェラーゼが機能していることが確認された。
実施例3と同様にして、実施例1で作製したP-M遺伝子間にGFPが挿入されたプラスミド(プラスミドpCAG-Fct-P/M-GFP、以下、「p/mGFP」という)から産生された組換えウイルスp/mGFPを新生仔マウスの頭蓋内に接種した。組換えウイルス接種2ヶ月後及び8ヶ月後に、マウスの大脳皮質及び小脳から採材を行ない(それぞれn=2)、実施例3と同様にして細胞へのウイルスの感染を、(1)N蛋白質抗体(抗BDV N抗体)及び蛍光標識抗体(モリキュラープローブ社製)を使用する間接免疫蛍光抗体法、並びに(2)GFPの蛍光により調べた。その結果、BDVウイルスは、接種から2ヶ月~8カ月間、感染細胞(マウスの大脳皮質及び小脳)で持続発現することが分かった。
G欠損ウイルスの回収
(1)プラスミドの構築
A) p/mGFP deltaG L linear (p/mGFP ΔG LL)の作製
実施例1で作製したp/mGFPを元に、ウイルス膜糖蛋白質であるG遺伝子をPCRを用いた点変異導入により欠損させた。具体的な方法として、G遺伝子に存在する2つのメチオニンをコードする配列(ゲノム番号(すなわち配列番号1の塩基)2236-2238、及び2248-2250)をスレオニン(ATG→ACG)へと置換した。図19に、G遺伝子欠損型ウイルスをコードするプラスミドであるp/mGFP ΔGの作製手順の概略を示す。先ずp/mGFPを鋳型に表1に示す配列のプライマーA1及びB1、並びにプライマーC1及びD1を用いてPCR(98℃ 10秒、55℃ 5秒、72℃ 0.5又は1分を25サイクル)を行った(図19(a))。
G欠損ウイルスを回収するために、ヘルパープラスミドとしてBDVのG蛋白質を哺乳類細胞で発現させるプラスミドを作製した。この手順の概略を、図21に示す。具体的な方法として、p/mGFPを鋳型にPCRでG遺伝子領域を増幅し、ニワトリベータアクチンプロモーターの下流に挿入した(上述した他のN、P及びL遺伝子のヘルパープラスミドと同様の方法)。先ず、表1に示すプライマーG1及びH1、並びにプライマーI1及びJ1を用いてp/mGFPを鋳型にPCR(98℃ 10秒、55℃ 5秒、72℃ 0.5又は1.0分を25サイクル)を行った(図21(a))。次に双方の増幅産物(1stPCR産物)を鋳型にプライマーG1及びJ1を用いてPCR(98℃ 10秒、55℃ 5秒、72℃ 1.5分を25サイクル)を行った(図21(b))。増幅産物(2ndPCR産物)はG遺伝子をコードしているが、BDVが本来有するスプライシングサイト(SD = 2409-2415、SA = 2437-2442)に、PCRの際に変異を導入し、機能しないようにしている(アミノ酸変異は無い)。具体的には、野生型BDV(WT)のゲノムの2409-2415番目のGGTTATGを、agtctccとし(ΔSA)、さらに野生型BDV(WT)のゲノムの2437-2442番目のGGTTATGを、agtctccとした(ΔSD)。この2ndPCR産物(ΔSDSA G遺伝子)を、制限酵素KpnI及びSmaIを用いて発現プラスミド(実施例1のヘルパープラスミドの作製で使用したpCXN2)に挿入し(図21(c))、BDV G遺伝子発現プラスミドを作製した。組換えプラスミドのヌクレオチド配列は、DNAシークエンスによって確認した。なお、本実験ではG遺伝子発現プラスミドの作製にpCXN2を使用したが、哺乳類細胞で遺伝子を発現できる他のプラスミドも使用可能である。
上記で使用したプライマーの配列を、表1に示す。
上記(1)A)で作製したG蛋白質発現プラスミドを用いてBDVのG遺伝子安定発現細胞を作製した。具体的な方法として、回収に用いる哺乳類培養細胞株、すなわち293T細胞及びVero細胞それぞれ1~5×105個を9.4 cm2の培養シャーレに撒き、翌日市販の遺伝子導入試薬(Fugen6、Lipofectamine2000)を用いて、上記(1)で作製したプラスミドDNAを2~5μg導入した。細胞の培養は、37℃でダルベッコ変法イーグルMEM培地を用いて行った。プラスミド添加から3日後細胞を継代し、新しい培養プレートに1/3量撒いた。その際、選択薬剤としてジェネティシン(G418)(Invitrogen:GIBCO)を1μg/mlの濃度でダルベッコ変法イーグルMEM培地に加えた。薬剤選択によって目的遺伝子が安定的に導入された細胞のみ生存するため、この方法によりG遺伝子安定発現細胞株(G遺伝子安定発現293T細胞及びG遺伝子安定発現Vero細胞)を単離した。
A) G遺伝子欠損ウイルス感染Vero細胞の回収
293T細胞にヘルパープラスミドとしてN、P、L及びG遺伝子を導入した。さらに上記で作製したp/mGFP ΔG又はp/mGFP ΔG LLを導入した(遺伝子導入方法は上記(2)と同じ)。各プラスミドを、N遺伝子=0.25μg、P遺伝子=0.025μg、L遺伝子=0.25μg、G遺伝子=0.01μg、p/mGFP ΔG又はp/mGFP ΔG LL=2.0μgという量比で細胞に導入した。遺伝子導入後、37℃で293T細胞を培養した。遺伝子導入3日後に細胞を継代し、その際上記で作製したG遺伝子安定発現Vero細胞と共培養を行った後、該Vero細胞を、G遺伝子欠損ウイルス感染Vero細胞として回収した。
上記(3)A)で作製した感染Vero細胞をトリプシン溶液(トリプシン0.03% w/v、EDTA/2Na 0.02% w/v in PBS-)を用いて培養プレートから回収し、室温にて100~150g、5分間遠心分離し細胞沈殿物を回収した。回収した細胞沈殿物をもう一度イーグルMEM培養液を用いて懸濁した。作製した懸濁液を、超音波細胞破砕機を用いて処理した。破砕処理後の懸濁液は4℃にて1000~1200g、25分間遠心分離し上清をウイルス液として回収した。p/mGFP ΔG及びp/mGFP ΔG LLのいずれを導入した細胞からも、組換えBDVが回収された。
ウイルス液は、必要に応じ超遠心機を用いて濃縮した。具体的な方法として、超遠心用のチューブに20%ショ糖液を加え、その上に上記(3)B)で回収したウイルス液を加えた。4℃にて50000~100000g、2時間遠心分離し、沈殿物をPBS-で再懸濁して濃縮液として回収した。
p/mGFP ΔG LL感染細胞の作製とシュードタイプウイルスの作製
(1)p/mGFP ΔG LL感染細胞の作製と持続感染性の確認
A)p/mGFP ΔG LL感染細胞の作製
実施例7の(3)B)又はC)で回収したウイルスをVero細胞に接種し、p/mGFP ΔG LL感染細胞を作製した。ウイルス液の希釈にはOpti-MEM(Invitrogen:GIBCO)を用い、24wellプレートに撒いた単層のVero細胞にウイルス希釈Opti-MEMを100μl接種し(Vero細胞1個につき、ウイルスを約0.1~0.01粒子)、37℃で1時間感作させた。その後PBS-を用いて細胞を洗浄しダルベッコ変法イーグルMEM培地にて37℃で培養を続けた。接種した感染細胞はウイルスが伝播しない為、細胞のクローニング法(限界希釈法)により100%感染細胞を分離した。感染細胞かどうかの判断は蛍光顕微鏡によりGFPの発現を観察し判断した。ここで分離した感染細胞は、後述するシュードタイプウイルスの作製にも用いた。
図22は、G遺伝子安定発現細胞への共培養後12日目の各細胞のウイルス陽性率をGFPを指標に測定したものである。図22から、細胞10万個当たりのGFP陽性細胞の数は、p/mGFP ΔGを用いた場合を1としたとき、p/mGFP ΔG LLはその約8倍の陽性率を示した。
このことから、p/mGFP ΔG LLは、p/mGFPΔGと比較して、組換えBDV産生能力が高いことが分かった。
実施例7の(3)B)又はC)で回収したウイルス(G欠損型組換えウイルス)をVero細胞又はG遺伝子安定発現Vero細胞にウイルス:細胞=1:100で接種し、増殖性及び持続性を観察した。感染率は、24wellプレートに撒いた細胞10万個あたりの感染細胞数をカウントすることにより測定した。その結果、図23に示すように、Vero細胞に接種した場合、感染率は約1%程度で推移したが、G遺伝子安定発現Vero細胞に接種した場合、経過とともに感染率は上昇した。このことから、BDVはG遺伝子なしでも持続感染するが(少なくても100日以上は観察)、感染を拡大するのにG遺伝子が必要であることが確認された。図23中、◆は、BDVのG遺伝子安定発現Vero細胞であり、■は、Vero細胞(G遺伝子を発現しない細胞)である。
図24aは、野生型BDV及びG欠損型組換えウイルスそれぞれを感染させた細胞における蛋白質の発現をウェスタンブロット法により調べた結果を示す。図24a中、G、N及びGFPは、それぞれG蛋白質、N蛋白質及びGFPである。図24bは、G欠損型組換えウイルスを感染させたVero細胞の蛍光顕微鏡写真である。図24bの写真で灰色見える部分はGFPによる緑色蛍光部分である。図24a及びbより、G遺伝子欠損ウイルスを感染させた細胞において、該ウイルスにより導入されたGFPが発現していることが確認された。
A)BDVG遺伝子細胞内領域と水疱性口内炎ウイルス(VSV)又は狂犬病ウイルス(RabV)のG遺伝子細胞外及び膜貫通領域を有するキメラ蛋白質発現プラスミドの作製
シュードタイプウイルスを作製するために、他のウイルスの膜蛋白質遺伝子を発現するプラスミドを作製した。図25に、手順の概略を示す。具体的な方法として、VSV(Indiana株)のG遺伝子発現プラスミド(GeneBank ID:J02428.1)を鋳型に、表2に示すプライマーA2及びB2を用いてPCR(98℃ 10秒、55℃ 5秒、72℃ 1.5分を25サイクル)を行った(図25(a))。増幅産物(PCR産物)は細胞内領域はBDV由来、細胞外及び膜貫通領域はVSV由来のキメラ膜蛋白(以下、キメラVSV-G蛋白質ともいう)をコードするDNA配列となっている。このPCR産物を制限酵素EcoRI及びEcoRVを用いて哺乳類細胞発現プラスミドであるpCXN2(実施例7の(1)B)参照)に組込み(図25(b))、VSV-G発現プラスミドを得た。
VSV及びRabVのG遺伝子の安定発現細胞株(VSV-G蛋白質安定発現株及びRab-G蛋白質安定発現株)を作製した。上記(2)A)で作製したプラスミド又は同様の方法で作製したTetシステム発現プラスミドに導入したプラスミドを用いてキメラ膜蛋白質安定発現細胞を作製した。具体的には実施例7の(2)に記載されている方法において、G蛋白質発現プラスミドの代わりに上記(2)A)で作製したキメラG蛋白質を発現するプラスミド又は同様の方法で作製したTetシステム発現プラスミドに導入したプラスミドを使用し、293T細胞及びVero細胞、並びに上記(1)で作製したp/mGFP ΔG LL感染細胞に導入した。Tetシステムの薬剤耐性濃度等は添付の説明書に記載の通りに行った。なお、今回用いたのはInvitrogen社のT-RExシステムである。
上記(1)A)で作製したp/mGFP ΔG LL感染細胞クローンを用いて、シュードタイプウイルスの回収を行った。具体的な方法として、p/mGFP ΔG LL感染細胞にキメラ膜蛋白質発現プラスミドを遺伝子導入し、ダルベッコ変法イーグルMEM培地またはNutrient Mixture F-12 HAM培地(SIGMA)中で37℃で培養後48-96時間後に上清をシュードタイプウイルス含有液として回収した。p/mGFP ΔG LLにコードされる組換えBDVゲノムを有し、VSV又はRabのウイルス膜蛋白質を被ったシュードウイルスが回収された。G遺伝子としてBDVのG遺伝子、並びにVSV及びRabの外殻遺伝子を用いた場合の、三者の間におけるウイルスの回収効率(粒子形成効率)の違いを、図26に示した。図26では、ウイルスの回収効率は、BDV のG遺伝子を使用したときを1とする相対値で表わされている。
さらに、実施例7(3)B)及びC)で示した方法と同様にして、キメラ蛋白質発現細胞を用いてVSV又はRabの膜蛋白質を被ったシュードタイプウイルスを回収した。これらのシュードタイプウイルスは、VSV又はRab由来の外殻を有し、かつp/mGFP ΔG LLにコードされる組換えBDVゲノムを発現できるシュードタイプウイルスである。
M及びG遺伝子欠損ウイルス
(1)p/mGFP ΔG LLをもとにM遺伝子を欠損させたプラスミドp/mGFP ΔM-G LLを作製した。
A)p/mGFP ΔM-G LLプラスミドの構築
さらなる安全性の向上と外来遺伝子挿入箇所の拡大を目的にBDVの膜裏打ち蛋白質をコードするM遺伝子を欠損させた。図27に、M遺伝子を欠損させたp/mGFP ΔM-G LLプラスミドの作製手順の概略を示す。具体的な方法として、p/mGFP ΔG LLを鋳型に、表3に示すプライマーA3及びプライマーB3を用いてPCR(98℃ 10秒、55℃ 5秒、72℃ 1.5分を25サイクル)を行った(図27(a))。得られたPCR産物(1stPCR産物)をPacIとNheIを用いてp/mGFP ΔG LLに挿入し、p/mGFP ΔM-G LLを作製した(図27(b))。
実施例7においてp/mGFP ΔG‐LLウイルスを回収したときと同様に、M蛋白質及びG蛋白質を両方共安定的に発現する培養細胞株を作製し(M遺伝子の選択薬剤にはゼオシンを使用した)、p/mGFP ΔM-G LLウイルスの回収を行った。
得られたp/mGFP ΔM-G LLウイルスをVero培養細胞に感染させたところ、野生株と同様に感染性を有することが確認された。
p/mGFP ΔM-G LL のp/m遺伝子間にもう一つ外来遺伝子挿入したカセットを作製した。
さらなる外来遺伝子を挿入する目的で、新たな外来遺伝子挿入カセットをp/m遺伝子間に挿入した。図28に、p/mGFP ΔM-G LL P-M tandem vectorの作製手順の概略を示す。具体的な方法として、p/mGFP ΔM-G LLを鋳型に表3に示すプライマーC3及びD3を用いてPCR(98℃ 10秒、55℃ 5秒、72℃ 0.5分を25サイクル)を行った(図28(a))。さらに、得られたPCR産物(1stPCR産物)を鋳型にプライマーC3及びE3(表3)を用いてPCR(98℃ 10秒、98℃ 5秒、72℃ 0.5分を25サイクル)を行った(図28(b))。得られたPCR産物(2ndPCR産物)を、EcoT22IとBstBIを用いてp/mGFP ΔM-G LLに挿入した。これにより新たな外来遺伝子挿入カセットSse8381I-SwaIをp/mGFP ΔM-G LLに挿入でき、p/mGFP ΔM-G LL P-M tandem vectorが得られた。
このカセットは、P遺伝子のORFとM遺伝子のORFの間にBstBI-PacIサイトを有する他のp/mベクターにEcoT22IとBstBIを用いて組込みことが可能である。
p/mベクターの利用
(1)アルツハイマー病の治療を目的としたp/mNEPベクターの作製
A)p/mNEPベクターの作製
アルツハイマー病の遺伝子治療法開発を目的にp/m遺伝子間にアミロイドベータ蛋白質(Aβ)分解酵素であるNeprilysin(NEP : Gene ID = 4311)を挿入したp/mNEPベクターを作製した。具体的な方法として、ヒト由来培養細胞からRNAを抽出し、oligodTをプライマーに逆転写酵素(Invitrogen、Super script III)によりmRNAの逆転写反応を行った。得られたcDNAを鋳型に、表6に示すプライマーA4及びB4を用いてNEPをPCR(98℃ 10秒、55℃ 5秒、72℃ 2.5分を25サイクル)により増幅した。得られたPCR産物をBstBI-PacIを用いてp/mGFPベクターと組換え、p/mNEPベクターを作製した。p/mNEPベクターは、実施例1で作製したBDVのP-M遺伝子間にGFPが挿入されたプラスミド(p/mGFP)において、GFPのcDNAがNEPのcDNAで置換されている。さらに、比較のため、NEP酵素活性部位に変異を加えたものをp/mベクターに挿入した組換えベクター(以下、比較ベクター1という)を作製した。方法としては、表6に示すプライマーA4及びC4、並びにB4及びD4を用いてp/mNEPを鋳型にPCR(98℃10秒、55℃5秒、72℃2分又は0.5分を25サイクル)を行った。次に双方の増幅産物(1stPCR産物)を鋳型にプライマーA4及びB4を用いてPCR(98℃10秒、55℃5秒、72℃2.5分を25サイクル)を行った。増幅産物(2ndPCR産物)はNEPのアミノ酸配列585番目がグルタミン酸(GAA)からバリン(GtA)に置換されており、これをBstBI-PacIを用いてp/mNEPベクターと組換え、比較ベクター1を作製した。
B)Vero細胞におけるp/mNEPの発現及び活性測定
上記で作製したp/mNEPベクターを用いて、実施例2と同様の方法により、p/mNEP感染Vero細胞を得た。
得られたp/mNEP感染Vero細胞が実際にNEPを発現しているかをWestern Blotting及び間接蛍光抗体法にて確認した。今回用いた一次抗体は抗CD10[56C6]マウスモノクローナル抗体(abcam社:ab951)である。図29に、p/mNEP感染細胞のWestern Blottingの結果を示す。図29中、NEPは、p/mNEPベクターから産生された組換えウイルスp/mNEP感染細胞であり、d.nは、比較ベクター1から産生されたウイルスが感染した比較細胞であり、n.cは、非感染細胞である。α-Nは、BDVのN蛋白質である。図29から、p/mNEPベクター及び比較ベクター1から産生された組換えウイルスが感染した細胞(比較細胞1)では、NEPが発現したことが確認された。
治療法開発に向け、先ずアルツハイマー病モデルマウスにp/mNEPを接種した。数多く存在するアルツハイマー病のモデルマウスの中で、今回はB6SJL-Tg(APPSwFlLon,PSEN1*M146L*L286V)6799Vas/J(Jackson研究所No6554)とB6.Cg-Tg(APPSwe,PSEN1dE9)85Dbo/J(Jackson研究所No5864)を使用した。これらのモデルマウスはいずれも、ヒトのAβ前駆蛋白質とその分解酵素プレセニリンの変異体を神経細胞に発現させたもので、出生後早期にアルツハイマー病様の症状を示すことが報告されている。
現時点で、p/mGFPベクターから産生された組換えウイルスを接種したマウスでは脳内に少なくとも8カ月間は導入したGFPの発現が確認された(実施例6及び図18)。このことからp/mベクターはアルツハイマー病のような長期経過を辿る神経疾患に適用できると考えられる。
(1)miRNA導入ベクターの開発
医療及び研究への応用に役立てるため、機能性RNAであるmiRNAを導入可能なp/mベクターを作製した。
A)p/m miR155導入用ベクター(pSIRIUS-B)の作製
pSIRIUS-Bの作製手順の概略を、図31に示す。まず、様々なmiRNA配列を導入するために必要となる導入用ベクターを作製した。初めにpBluescript SK-のマルチクローニングサイトにBstBIとPacIの制限酵素サイトを導入し(図31(b))、p/m miR155導入用ベクターpSIRIUS-Bを完成させた。次にその間にmiR 155をもとに設計したmiRNA発現に必要な制御配列を導入した。さらに、その中心にはBbsIによる制限酵素カセットを挿入し、様々なmiRNA配列を導入できるようにした(図31(a))。
図31(a)の模式図において、白い部分がmiRNA発現制御部位であり、黒い部分がオリゴ導入カセットである。図31(a)に模式的に示されるDNA断片の配列及び該配列内の制限酵素サイトを、下記表4に示す。
A)で作製したベクターを利用して様々なmiRNA配列をBstBI、PacIを用いてp/mベクターに挿入することが可能である。今回は一例としてmiR155を用いた。miR155標的配列を合成し、これをpSIRIUS-BにBbsIを用いて導入し、pSirius-B miR-155を得た(図32(a))。表5に、今回合成したmiR155標的配列の配列を示す。上段が、miRNA155の配列(配列番号32)である。表5の下段の配列を配列番号33に示す。miR155標的配列(オリゴ)を、pSirius-B miR-155から、BstBI-PacIを用いてp/mベクターに導入し、p/m miR155を作製した(図32(b))。
実施例2に示した方法と同様の方法によりp/m miR155のプラスミドから組換えウイルスを回収し、B)で作製したプラスミドを用いてその活性を測定した。方法として、p/m miR155感染細胞及びBDV野生株感染細胞(いずれもVero細胞にウイルスを感染させた)に遺伝子導入試薬(Lipofectamine2000など)を用いてレポータープラスミドを導入し、2~3日後Luciferase Assay System(Promega社)に添付のプロトコール通りに実験を行い、p/m miR155感染細胞とBDV野生株感染細胞とを比較した。図33に、組換えウイルスを感染させた細胞における標的遺伝子の転写阻害効率を示す(図33のwt: BDV野生株感染細胞、x1:p/m miR155感染細胞)。
さらに、a)を改良しmiRNAの配列をx2(2回繰り返した配列)、x4(4回繰り返した配列)で挿入することができるように新たなプラスミドを作製した。作製手順の概略を、図34に示す。まずpcDNA3のマルチクローニングサイトにBstBIとPacIを挿入した(pSIRIUS-D)。次にA)で作製したプラスミド(目的のmiRNA挿入済み)を鋳型に表6に示すプライマーE4及びF4を用いてPCRを行った(98℃ 10秒、55℃ 5秒、72℃ 0.5分を25サイクル)。得られたPCR産物をpSIRIUS-DにSalIとXhoIを用いて挿入した(図34(a))(このとき挿入される向きに注意した)。さらに、作製したプラスミドからSalIとXbaIでインサートを切り出し(図34(b))、得られた断片をもう一度同一のプラスミドに今度はXhoIとXbaIを使って挿入した(SalIとXbaIは同一の切断配列を有した)(図34(c))。これによりmiRNAx2のプラスミドが得られた。得られた、miRNAx2のプラスミドをBstBIとPacIで切り出してp/mベクターに挿入することにより、p/m miRNAx2が得られた。miRNA x4は上記工程を繰り返すことによって作製した。miRNA×2及びmiRNA×4のp/mベクターの模式図を、図35に示す。得られたmiRNA×2及びmiRNA×4のp/mベクターを、実施例2に示した方法と同様の方法により回収し、その効果を確認した。結果を、図33に示す。図33中、×1、×2、及び×4はそれぞれ、プラスミド中に挿入したmiR155の数である。図33から分かるように、miR155が導入された数が多いほど、標的遺伝子の発現が効率よく阻害された。また、細胞に導入されたmiR155は、細胞で持続的に発現することが確認され、本発明のベクターは、機能性RNAを発現できるRNAベクターとして有用であることが示された。
A)p/m miRNA GAPDHを用いたマウス海馬初代培養細胞におけるmiRNAの効果
p/m miRNA155において、miRNA155の代わりに細胞内で恒常的に発現しているGAPDHに対するmiRNA(miR-GAPDH)を挿入したプラスミド(p/m miRNA-GAPDH)を作製し、その効果をより生体に近いマウス海馬初代培養細胞で確認した。p/m miRNA-GAPDHの作製方法は(1)で示したp/m miR155の作製方法とほぼ同様である(合成したmiR-GAPDHの配列を、配列番号40及び41に示した)。配列番号40のDNA及び配列番号41のDNAは、プラスミド内では二重鎖を形成している。実施例2に示した方法と同様の方法によりp/m miRNA-GAPDHから産生された組換えウイルスp/m miRNA-GAPDHを回収した。回収した組換えウイルスp/m miRNA-GAPDHを新生仔マウスの海馬から採取した初代培養細胞にMOI=0.01で接種した。7日後に固定後、抗BDV-N抗体、及び抗GAPDH抗体で染色し、蛍光顕微鏡にて観察した。その結果、組換えウイルスp/m miR-GAPDHを感染させた細胞では野生型BDVを感染させた細胞に比べ有為にGAPDHの発現が抑制されていた(図36)。図36a及びbは、野生型BDVを感染させた細胞であり、図36c及びdは、組換えウイルスp/m miR-GAPDHを感染させた細胞である。図36a及びcは、抗BDV-N抗体で染色した細胞の蛍光顕微鏡写真であり、図36b及びdは、抗GAPDH抗体で染色した細胞の蛍光顕微鏡写真である。図36b及びdの四角内は、拡大写真であり、**を付した矢印は、非感染細胞を示す。**が付されていない矢印は、感染細胞(図36bでは野生型、図36dではp/m miR-GAPDH)を示す。図36bでは非感染細胞、感染細胞共にGAPDHの発現レベルは高い(GAPDHは抑制されていない)が、図36dでは感染細胞は非感染細胞に比べGAPDHの発現レベルが抑制されていることが観察された。
p/m miRNA155において、miRNA155の代わりにアルツハイマー病の原因蛋白質であるAPPに対するmiRNA(miRNA-APP)を挿入したプラスミド(p/m miRNA-APP) を作製し、その効果をp/m miRNA-APP感染Vero細胞を用いて確認した。p/m miRNA-APPの作製方法は(1)で示したp/m miR155の作製方法とほぼ同様である(合成したmiRNA-APPを、配列番号42及び43に示した)。配列番号42のDNA及び配列番号43のDNAは、プラスミド内では二重鎖を形成している。実施例2に示した方法と同様の方法によりp/m miRNA-GAPDHから産生された組換えウイルスp/m miRNA-APPを回収した。回収した組換えウイルスp/m miRNA-APPを感染させた細胞にLipofectamine2000を用いてAPP発現プラスミド(pcDNA3に添付の説明書に従って作製。APPのcDNA(Accession No=NM_000484)はヒト由来培養細胞からRNAを抽出し、oligo dTプライマー及び逆転写酵素を用いて調製した。)を添付の説明書に従って導入した。48時間後にRNAを回収し、上記表6に示すAPPに特異的なプライマーG4及びH4を用いた定量的RT-PCR(95℃10秒、60℃30秒、40サイクル)によりAPPのmRNAのレベルを確認した。コントロールとして、p/mGFPから産生された組換えウイルスを感染させた細胞を用いて同様の実験を行なった。その結果、組換えウイルスp/m miRNA-APPが感染したVero細胞ではp/mGFPが感染したVero細胞に比べ有為にAPPのmRNAの量が低下していた(図37)。
Claims (14)
- (a)ボルナ病ウイルスゲノムにおける少なくともN遺伝子、X遺伝子、P遺伝子及びL遺伝子を、ボルナ病ウイルスゲノムにおける順序と同じ順序で有し、前記P遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNA、(b)リボザイムをコードするDNA及び(c)プロモーター配列を含み、該(a)の上流及び下流に(b)が配置され、かつ(a)及び(b)が(c)の下流に配置されていることを特徴とするウイルスベクター。
- (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムにおいてG遺伝子が破壊された配列を有し、かつP遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNAである請求項1に記載のウイルスベクター。
- (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムにおいてG遺伝子及びM遺伝子が破壊された配列を有し、かつP遺伝子の翻訳領域の下流に連結する非翻訳領域内に外来性遺伝子が挿入された配列を有する組換えウイルスRNAのcDNAである請求項1又は2に記載のウイルスベクター。
- (a)組換えウイルスRNAのcDNAが、ボルナ病ウイルスゲノムをコードするcDNAのP遺伝子の翻訳領域とM遺伝子の翻訳領域との間の非翻訳領域に外来性遺伝子を挿入した組換えウイルスのcDNAである請求項1に記載のウイルスベクター
- (c)プロモーター配列が、RNAポリメラーゼII系のプロモーター配列であることを特徴とする請求項1~4のいずれかに記載のウイルスベクター。
- (a)組換えウイルスRNAのcDNAの上流に(b1)ハンマーヘッドリボザイムをコードするcDNAが配置され、かつ、該(a)の下流に(b2)δ型肝炎ウイルスリボザイムをコードするcDNA配列が配置されていることを特徴とする請求項1~5のいずれかに記載のウイルスベクター。
- 請求項1~6のいずれかに記載のウイルスベクターにコードされるRNAを含むことを特徴とする組換えウイルス。
- 請求項1~6のいずれかに記載のウイルスベクターと共に、ヘルパープラスミドとしてボルナ病ウイルスのN遺伝子、P遺伝子及びL遺伝子を発現するプラスミド又はプラスミド群をin vitroの細胞に導入する工程、及び該ウイルスベクター及びヘルパープラスミドを導入した細胞を培養して組換えウイルスを産生させる工程を含むことを特徴とする組換えウイルスの作製方法。
- ヘルパープラスミドとして、さらに、ウイルスの外殻遺伝子を発現するプラスミドをin vitroの細胞に導入する請求項8に記載の組換えウイルスの作製方法。
- ヘルパープラスミドとして、さらに、ボルナ病ウイルスのM遺伝子を発現するプラスミドをin vitroの細胞に導入する請求項8又は9に記載の組換えウイルスの作製方法。
- 請求項7に記載の組換えウイルス、又は請求項8~10のいずれかに記載の方法により作製された組換えウイルスをin vitroの細胞又は動物に感染させる工程を含むことを特徴とする外来性遺伝子の導入方法。
- 請求項7に記載の組換えウイルス、又は請求項8~10のいずれかに記載の方法により作製された組換えウイルスを含有することを特徴とする外来性遺伝子導入剤。
- 請求項7に記載の組換えウイルス、又は請求項8~10のいずれかに記載の方法により作製された組換えウイルスを含有することを特徴とする脳神経系細胞への外来性遺伝子導入剤。
- 請求項1~6のいずれかに記載のウイルスベクターを含有することを特徴とする外来性遺伝子導入用キット。
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WO2018168586A1 (ja) | 2017-03-14 | 2018-09-20 | 国立大学法人京都大学 | ボルナウイルスベクター及びその利用 |
WO2023033050A1 (ja) | 2021-09-02 | 2023-03-09 | 国立大学法人京都大学 | ボルナウイルスベクターを利用した医薬組成物 |
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Publication number | Priority date | Publication date | Assignee | Title |
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JP2017000015A (ja) * | 2015-06-04 | 2017-01-05 | 国立大学法人京都大学 | 目的遺伝子の発現誘導可能なウイルスベクター |
WO2018168586A1 (ja) | 2017-03-14 | 2018-09-20 | 国立大学法人京都大学 | ボルナウイルスベクター及びその利用 |
JP2018148865A (ja) * | 2017-03-14 | 2018-09-27 | 国立大学法人京都大学 | ボルナウイルスベクター及びその利用 |
US11421247B2 (en) | 2017-03-14 | 2022-08-23 | Kyoto University | Borna viral vector and use thereof |
WO2023033050A1 (ja) | 2021-09-02 | 2023-03-09 | 国立大学法人京都大学 | ボルナウイルスベクターを利用した医薬組成物 |
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