The two recognition detection method of TALEs and application thereof
Technical field
The invention belongs to biology field, be specifically related to a kind of two recognition detection method of TALEs and application thereof.
Background technology
TALE (Transcription Activator Like Effectors) is a class DBP.Its DNA binding domains is made up of the repeating unit of variable number, natural TALEs is primarily of being positioned at the encoding transport signals (translocation signal) of N end, being positioned at nuclear localization signal (the nuclear localization signals of C end, and transcriptional activation domain (transcriptional activation domain, AD) and be positioned at middle DNA binding domains three part composition NLS).DNA binding domains is generally 34 by comprising 33 ~ 35() repeating unit of individual amino-acid residue is in series, mediated dna specific recognition and combination.Each repeating unit sequence high conservative, the key distinction be the 12nd and the 13rd repeat variable pair of residue (repeat variant di-residue, RVD).Research finds that the RVD of each repeating unit determines its Nucleotide identified, and a simple rule is followed in its identification: NI=A, HD=C, NG=T, NN=G or A.TALEs can identify any DNA sequence in theory.
Also be not used for the diagnosis of gene at present with TALEs albumen, the two recognition detection technology of TALEs of the present invention, does abrupt climatic change with it.The method not only may be used for the detection of scientific research, also may be used for clinical diagnosis.
Summary of the invention
the technical problem solved:
The object of the invention is to overcome the deficiencies in the prior art and the two recognition detection method of a kind of TALEs of developing, the method can detect different genes, point mutation etc., can be used for the research of molecular diagnosis, genetic expression, detection sensitivity of the present invention is higher, and false positive rate is lower.
technical scheme:
The present invention utilizes TALEs to identify the characteristic of DNA, expresses the TALEs albumen of specific recognition DNA sequence dna, then identifying that the albumen of different DNA sequence dna is coated on microwell plate.Subsequently add DNA sample and the TALEs protein binding be coated on microwell plate, then add the TALEs albumen that coupling has alkaline phosphatase again, this albumen specific recognition DNA sequence dna, finally adds the substrate of alkaline phosphatase, chemiluminescence detection.Thus detect different genes, point mutation etc.
The two recognition detection method of TALEs, step is as follows:
Step one: the structure of TALEs prokaryotic protein expression plasmid: cut pET-16b carrier with NdeI and BamHI, then NdeI and the BamH site of TALEs sequence clone to pET-16b carrier, obtains pET-16b-TALEs prokaryotic expression carrier;
Step 2: prokaryotic expression TALEs albumen: pET-16b-TALEs prokaryotic expression carrier step one prepared is transformed in e. coli bl21, IPTG induces, collect bacterium and lysing cell, centrifuging and taking supernatant liquor, carries out Ni post affinity chromatography, after treating that target protein is combined with Ni post, with rinsing liquid washing, rear elution buffer rinses, and the high-salt buffer in elution fraction is replaced as PBS solution, finally carry out the detection of SDS-PAGE, gained is the TALEs albumen of purifying.
Step 3: the directed high-density of TALEs albumen is coated on microwell plate.Add the DNA sample of extraction, DNA is coated on the TALEs albumen Packet capturing on microwell plate.
Step 4: the DNA having the TALEs albumen identification of alkaline phosphatase captured with coupling, adds the substrate of alkaline phosphatase, produce chemiluminescence signal, and interpretation signal.
The two application of recognition detection method in gene diagnosis of described TALEs.
beneficial effect
The present invention breaks the nucleic acid bind nucleic acid of gene chip, the characteristic of albumen identification albumen in protein chip, with protein-specific identification DNA, stable, and remolding sensitivity is higher, may be used for quick diagnosis.Compared with prior art, advantage of the present invention is can the different gene of high throughput testing and multiple mutational site, and the method not only may be used for the detection of scientific research, also can be used as clinical diagnosis.
Accompanying drawing explanation
Fig. 1 is the signal results figure detected with chemoluminescence method, and as shown in Figure 1, TALEs detects the detected result in EGFR gene T790M site to result.
Embodiment
By reference to the accompanying drawings the present invention is described in further detail below by embodiment.But it will be understood to those of skill in the art that the following example only for illustration of the present invention, and should not be considered as limiting scope of the present invention.Unreceipted concrete technology or condition person in embodiment, according to the technology described by the document in this area or condition or carry out according to product description.Agents useful for same or the unreceipted production firm person of instrument, being can by the conventional products of commercial acquisition.
embodiment 1
1, material: pET-16b is purchased from Novagen, e. coli bl21 is purchased from Takara, and the TALEs albumen being marked with alkaline phosphatase is marked by Beijing Bo Aosen Bioisystech Co., Ltd.
2, method
Step one: the structure of TALEs prokaryotic protein expression plasmid: cut PET-16b carrier with NdeI and BamHI, then NdeI and the BamH site of TALEs sequence clone to pET-16b carrier, obtains pET-16b-TALEs prokaryotic expression carrier;
Step 2: prokaryotic expression TALEs albumen: pET-16b-TALEs prokaryotic expression carrier step one prepared is transformed into e. coli bl21, IPTG induces, collect bacterium and lysing cell (50mM NaH2PO4, pH 8.0,300mM NaCl, 10mM imidazoles), centrifuging and taking supernatant liquor, carry out Ni post affinity chromatography, after treating that target protein is combined with Ni post, first use rinsing liquid (50mM NaH
2p0
4, pH 8.0,300mM NaCI, 20mM imidazoles) and washing, use elution buffer (50mM NaH afterwards
2p0
4, pH8.0,300mM NaCI, 250mM imidazoles) rinse, by high-salt buffer (the 50mM NaH in elution fraction
2p0
4, pH8.0,300mM NaCI, 250mM imidazoles) and be replaced as PBS solution, finally carry out the detection of SDS-PAGE, gained is the TALEs albumen of purifying;
Step 3: TALEs albumen orientation is coated on microwell plate, adds DNA sample, DNA is coated on the TALEs albumen Packet capturing on microwell plate;
Step 4: with the DNA that the TALEs albumen identification being marked with alkaline phosphatase is captured, add the substrate of alkaline phosphatase, produce chemiluminescence signal, and interpretation signal.
embodiment 2
Detect the sudden change of the T790M of human epidermal growth factor acceptor (EGFR) gene 20 exon
1. the TALEs probe of selective recognition wild-type T790 sequence: TALEs-T790(CGACATCACGCAGCTC) (SEQ ID NO.1), identify the TALEs probe of the sequence of 790M: TALEs-790M(CGACATCATGCAGCTC) (SEQ ID NO.2), identify the TALEs probe of negative control sequence: TALEs-control(CGACATCTCGTAGCTC) (SEQ ID NO.3) build the recombinant plasmid pET-16b-TALEs-T790 (CGACATCACGCAGCTC) of prokaryotic expression, pET-16b-TALEs-790M E (CGACATCATGCAGCTC) and pET-16b-TALEs-control(CGACATCTCGTAGCTC).These three vector intestinal bacteria E. coli BL21: transformed bacteria overnight incubation in the substratum of 5ml ammonia benzyl resistance, be transferred to next day in the identical substratum of 500ml and cultivate, through IPTG16 DEG C of induction of spending the night, collect the TALEs-790M obtained, TALEs-790M and TALEs-control albumen thalline, the albumen of centrifugal acquisition solubility after high pressure fragmentation, carries out Ni post affinity chromatography.After treating that target protein is combined with Ni post, first use rinsing liquid (20mM Tris-HCl, 500mM NaCl, 5%(v/v) glycerine, 60mM imidazoles, pH8.0) wash, use elution buffer (20mM Tris-HCl, 500mM NaCl, 5%(v/v) glycerine afterwards, 500mM imidazoles, pH8.0) wash away albumen.PD-10 desalting column is utilized to be replaced as the high-salt buffer in elution fraction containing 20%(volume percent) PBS solution of glycerine, carry out the detection of SDS-PAGE afterwards, gained is the TALEs-T790 of purifying, TALEs-790M and TALEs-control albumen.
2.TALEs-T790 is coated on microwell plate.With being marked with the TALEs-T790 albumen of avidin and combining with 9 orifice plates of Streptomycin sulphate, TALEs-T790 albumen is just coated on microwell plate.
3. add the DNA sample extracted and carry out hybrid capture, remove the DNA of non-specific binding.Then the TALEs-790M albumen of alkaline phosphatase there is is to join IC1 coupling, in IC2 hole, there is the TALEs-control albumen of alkaline phosphatase to join in other holes coupling, finally add the substrate of alkaline phosphatase, produce chemiluminescence signal, and interpretation signal.
Table 1 sequence
|
Sequence |
SEQ ID NO. |
Identify the TALEs-T790 probe of wild-type T790 sequence |
CGACATCACGCAGCTC |
1 |
Identify the TALEs-790M probe of the sequence of 790M |
CGACATCATGCAGCTC |
2 |
Identify that the TALEs-control of negative control sequence visits |
CGACATCTCGTAGCTC |
3 |