WO2017126646A1 - 核酸アプタマーをスクリーニングするための方法 - Google Patents
核酸アプタマーをスクリーニングするための方法 Download PDFInfo
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- C12N15/09—Recombinant DNA-technology
- C12N15/11—DNA or RNA fragments; Modified forms thereof; Non-coding nucleic acids having a biological activity
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- C12Q2531/00—Reactions of nucleic acids characterised by
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- C12Q2565/00—Nucleic acid analysis characterised by mode or means of detection
- C12Q2565/50—Detection characterised by immobilisation to a surface
- C12Q2565/518—Detection characterised by immobilisation to a surface characterised by the immobilisation of the nucleic acid sample or target
Definitions
- the present invention relates to a method for screening a nucleic acid aptamer.
- Nucleic acid aptamers are single-stranded DNA or RNA having molecular recognition ability, and were first reported in 1990 by Ellington et al. And Tuerk et al. Nucleic acid aptamers can be obtained by an evolutionary technique called Systematic Evolution of Ligands by Exponential Enrichment (SELEX), and many have been reported to have binding ability and specificity comparable to antibodies. Furthermore, aptamers can be obtained for various targets such as proteins and cells, and low molecular compounds for which it is difficult to obtain antibodies, and application to therapeutic agents and diagnostic agents is expected. However, the acquisition probability of antibodies is said to be 90% or more, whereas the acquisition probability of current nucleic acid aptamers is said to be 30% or less. That is, it can be said that improvement of nucleic acid aptamer acquisition probability technology is a major issue for the future widespread use of nucleic acid aptamers.
- Nucleic acid aptamers are attracting attention as new molecular recognition elements replacing antibodies, but the acquisition rate of nucleic acid aptamers is 30% or less, and the development of highly efficient aptamer acquisition methods is desired.
- CE-SELEX is a rapid nucleic acid aptamer screening method that utilizes the excellent resolution of capillary electrophoresis.
- the setting of the sorting area is an important factor that determines the aptamer acquisition rate. It is necessary to sort out a region containing the ssDNA library that does not have the ability to bind to the target and does not contain a ssDNA library that forms a complex with the target.
- the ideal sorting region is the peak range derived from the ssDNA library and target complex.
- the target molecule is likely to interact with ssDNA like MutS protein and a highly sensitive fluorescence detector is not used, it is difficult to detect the complex of the ssDNA library and the target.
- Non-patent Document 1 Non-patent Document 1
- the present invention provides a novel CE-SELEX that takes advantage of CE-SELEX and solves the drawbacks such as difficulty in setting experimental conditions and the lack of applicable target molecular species.
- the present invention relates to a method for screening a nucleic acid aptamer that combines particles and CE-SELEX. So far, methods for quantitative analysis of RNA and antigen combining particles and capillary electrophoresis have been reported, but methods for combining particles and CE-SELEX have not yet been reported.
- the present invention relates to the following. [1] The following steps: (A) contacting a target molecule immobilized on a solid phase carrier with a nucleic acid aptamer candidate; (B) separating a nucleic acid aptamer candidate bound to a target molecule by capillary electrophoresis; (C) amplifying a nucleic acid aptamer candidate by PCR; A method for screening nucleic acid aptamers comprising: [2] The method according to [1], further comprising (d) single-stranded the amplified PCR product; [3] The method according to [1] or [2], wherein the solid support is a particle; [4] The method according to any one of [1] to [3], wherein the minimum particle diameter is 0.05 ⁇ m; [5] The method according to any one of [1] to [4],
- any material capable of immobilizing a target molecule on the surface can be used.
- layered graphene, carbon nanotubes, fullerenes and particles can be mentioned.
- any conventionally known particles can be used. Examples thereof include silica beads, polystyrene beads, latex beads, and metal colloids.
- the particles of the present invention can be magnetic particles.
- the maximum value of the average particle diameter of the particles can be determined according to the inner diameter of the capillary. Preferably, it is 100 ⁇ m, more preferably 10 ⁇ m, and even more preferably 1 ⁇ m.
- the minimum value of the average particle size of the particles is preferably 100 nm, more preferably 10 nm, even more preferably 1 nm.
- the average particle diameter of the particles can be determined using any known method.
- a sieving method, a microscope method, a sedimentation method, a laser diffraction scattering method, and an electric detection method can be exemplified.
- microscopy is used.
- the particle In order to use a visible light absorbance detector without using an expensive fluorescence detector, the particle needs to have a sufficient particle size to be detected by scattering of visible light.
- the minimum value of the average particle diameter of the particles is preferably 0.05 ⁇ m, more preferably 0.5 ⁇ m, and even more preferably 5 ⁇ m.
- the target molecule refers to a molecule that is a detection target in a detection method using a nucleic acid aptamer.
- the chemical species of the target molecule is not particularly limited, and can include various chemical species such as a low molecular compound, a high molecular compound, and a biological substance.
- the target molecule can be immobilized on the surface of the solid phase carrier. More specifically, examples include saccharides, lipids, oligopeptides, proteins, and nucleic acids. Examples of target molecule functions include antigens, antibodies, ligands, receptors, interacting proteins, and the like.
- the nucleic acid aptamer refers to a nucleic acid molecule that has a high affinity for a predetermined target molecule and can specifically bind thereto.
- a nucleic acid molecule having such properties is called a nucleic acid aptamer, and is not limited by the base sequence, the size of the molecule, the three-dimensional structure of the molecule, etc. unless otherwise specified.
- the nucleic acid aptamer is single stranded RNA or DNA.
- the target molecule immobilized on the solid phase carrier means that the target molecule is hydrophobic interaction, electrostatic interaction, covalent bond, coordinate bond, non-covalent intermolecular interaction (biotin-streptavidin Etc.) is fixed on the surface of the solid support.
- the nucleic acid aptamer candidate means a pool composed of a plurality of RNAs and / or DNAs.
- a single-stranded nucleic acid library consisting of a single-stranded nucleic acid is preferred, and a single-stranded DNA library consisting of a single-stranded DNA is more preferred.
- a part of the double-stranded nucleic acid formed by pairing all or part of the bases of the single-stranded nucleic acid may be included.
- capillary electrophoresis means that the capillary is filled with an aqueous solution, and an aqueous solution containing the target substance is introduced and placed in an electric field, so that effects such as charge transfer and affinity and electroosmotic flow work, and separation and purification. Will be possible.
- An arbitrary capillary inner diameter can be used.
- nucleic acid aptamer candidates bound to the target molecule are collected by capillary electrophoresis.
- a capillary tube that has been pretreated is installed in the capillary electrophoresis system.
- electrophoresis is performed in a running buffer.
- the absorbance at wavelengths such as 195, 260, 280, and 550 nm can be measured over time with a diode array detector, and the magnetic particle portion can be recovered using the obtained peak as an index ((a ) Step and (b) step).
- the sorted nucleic acid aptamer candidate is amplified by PCR.
- PCR is a polymerase chain reaction, and a specific DNA region can be amplified several hundred thousand times by repeating a DNA synthesis reaction by a DNA synthesizing enzyme in a test tube.
- the primer used at this time varies depending on the fixed sequence (sequence complementary to the primer sequence) of the DNA library to be used, and examples thereof include AGCAGCACAGAGGGTCAGATG (forward primer) and TTCACGGGTAGCACGCATAGG (reverse primer).
- DNA polymerase, Tris-HCl, KCl, MgCl 2 , and dNTPs are mixed with the separated nucleic acid aptamer candidates, the heating temperature and time are adjusted with a thermal cycler, and the cycle is repeated, so that the DNA region is It can be amplified (step (c)).
- the amplified PCR product is optionally made into a single strand.
- a PCR product amplified using a biotinylated primer is mixed with streptavidin-immobilized magnetic particles (for example, magnosphere MS300 / Streptavidin (Invitrogen)), and the steps of removing and washing the supernatant are repeated as appropriate. Thereafter, NaOH of an appropriate concentration is added to elute the target ssDNA from the surface of the magnetic particles and collect it (step (d)).
- streptavidin-immobilized magnetic particles for example, magnosphere MS300 / Streptavidin (Invitrogen)
- the above steps (a) to (d) can be arbitrarily repeated.
- the above steps (a) to (d) are repeated a maximum of 3 times.
- the present invention is a very simple method of immobilizing a target molecule on the particle surface, but in theory it may be able to solve almost all the problems that CE-SELEX has so far.
- the setting of the sorting area in CE-SELEX (hereinafter referred to as MB-CE-SELEX) using the magnetic particles of the present invention is much easier than in conventional CE-SELEX. Since the particles can be detected with high sensitivity by light scattering, an expensive fluorescence detector is unnecessary.
- a peak derived from magnetic particles can be used as a fractionation region (FIG. 2).
- FOG. 2 fractionation region
- the present invention has an excellent acquisition rate as compared with the conventional CE-SELEX. Therefore, a desired aptamer can be selected with a smaller number of rounds.
- the differences between the conventional SELEX and the present invention will be described below.
- FIG. 1 shows the difference between the conventional CE-SELEX and the present invention.
- FIG. 2 shows the evaluation of the binding ability of thrombin aptamer candidates using the SPR sensor (conventional CE-SELEX).
- Each figure A to J (10 in total) shows the examination results of 10 aptamer candidate sequences shown in the upper part of Table 3.
- FIG. 3 shows the evaluation of the binding ability of thrombin aptamer candidates using the SPR sensor (MB-CE-SELEX of the present invention).
- Each figure A to J (10 in total) shows the examination results of 10 aptamer candidate sequences shown in the middle of Table 3.
- FIG. 4 shows the evaluation of the binding ability of thrombin aptamer candidates using the SPR sensor (MB-CE-SELEX improved version of the present invention).
- FIG. 5 shows T_beads_re_apt. 1, T_beads_re_apt. 5 unique dissociation phases are shown.
- A 200 nM T_beads_re_apt. It is a response curve of 1 and an enlarged view.
- B 200 nM T_beads_re_apt. 5 is a response curve of 5 and an enlarged view.
- FIG. 6 shows the acquisition rate of thrombin aptamer in each selection method (calculated from only the top 10 sequences).
- Magnetic particles having carboxy groups on the surface Dynabeads MyOne (trademark) Carboxylic Acid (Invitrogen) were used as a carrier to immobilize molecules according to the protocol attached to the product.
- 100 ⁇ l of 20 mM Tris-HCl, 10 mM NaCl, 1 mM MgCl 2 buffer (pH 7.4) was added and stored at 4 ° C. as a magnetic particle stock solution of 10 mg / ml.
- CE-SELEX condition optimization Capillary electrophoresis conditions A capillary electrophoresis system (Agilent 7100: Otsuka Electronics) was used.
- As the capillary a 75 ⁇ m inner diameter bubble cell fused silica capillary (Agilent technologies) having a length of 80.6 cm and an effective length (length to the detection window) of 72.2 cm was used.
- the capillaries were set in a cassette so that capillaries of equal length emerged between the electrodes on the inlet side (injection port, positive electrode side) and outlet side (elution port, cathode side).
- 0.1 M NaOH aqueous solution was allowed to flow for 10 to 20 minutes by applying a pressure of about 1 bar.
- the inside of the capillary was equilibrated by flowing a running buffer (100 mM borate buffer, pH 8.5) for 10 to 20 minutes.
- sample buffer (20 mM Tris-HCl, 10 mM NaCl, 1 mM MgCl 2 buffer, pH 7.4).
- sample buffer 20 mM Tris-HCl, 10 mM NaCl, 1 mM MgCl 2 buffer, pH 7.4
- ssDNA library a total of 70 mer of synthetic oligo DNA in which both ends (5 ′ side and 3 ′ side) of a 30 mer random sequence were sandwiched by a 20 mer fixed sequence was used.
- Sample buffer and 100 ⁇ M ssDNA library were placed in a PCR tube and mixed by pipetting.
- the ssDNA library solution was heated at 95 ° C. for 2 minutes by a thermal cycler (Takara Bio), and then cooled to 25 ° C. at a rate of 0.1 ° C. per second to carry out annealing.
- V is the injection amount (nl)
- ⁇ P is the pressure change (bar)
- d is the capillary inner diameter (m)
- ⁇ is the circumference
- T is the injection time (s)
- ⁇ is the solution viscosity
- L is the total capillary length (m) Represents.
- V ⁇ Pd 4 ⁇ T / 128 ⁇ L ⁇ 10 12 [nL]
- Amplification of preparative sample by PCR A ssDNA sample fractionated by capillary electrophoresis was amplified by PCR. In a 1.5 ml tube, mix 2 ⁇ premix 400 ⁇ l, DEPC treated water 192 ⁇ l, 4 ⁇ M forward primer 80 ⁇ l, 4 ⁇ M 5′-biotinylated reverse primer 80 ⁇ l and mix in 8 200 ⁇ l PCR tubes 94 ⁇ l each. Dispensed. 6 ⁇ l of the aliquot sample was added to each of the 6 tubes, and 6 ⁇ l each of 1 to 10 pM ssDNA library and DEPC-treated water were added to the remaining two tubes as positive / negative controls. After heating at 94 ° C.
- Nucleotide sequence analysis by next-generation sequencer Sample preparation and emulsion PCR A sample for emulsion PCR was prepared according to the attached protocol, and it was confirmed by PAGE whether the DNA of the desired size was amplified. Thereafter, column purification of the PCR product was performed by Fast Gene Gel / PCR Extraction Kit (Nippon Genetics). Finally, emulsion PCR and bead purification were performed using Ion OneTouch TM 2 system (Life Technologies) and Ion PGM Template OT2 200 Kit (Life Technologies). The attached protocol referred to is Publication Number MAN0007220, Rev. 5.0.
- Biacore X100 (GE healthcare) was used to immobilize target protein on the sensor surface and analyze interaction with aptamer according to the attached manual.
- HBS-EP HBS-EP (HEPES, 150 mM NaCl, pH 7.0) was used as the running buffer.
- Carboxymethyldextran-modified CM5 sensor chip (GE healthcare) was set in the channel, and an EDC / NHS solution was allowed to flow at a flow rate of 10 ⁇ l / min for 7 minutes to activate the carboxy group on the sensor chip.
- aptamer candidates for which a specific response was obtained a plurality of diluted samples were prepared in the range of 6.25 to 400 nM, and multikinetic analysis was performed. However, aptamer candidates that could not be regenerated with 1M NaCl solution were subjected to single kinetic analysis (the regeneration process was not sandwiched in the middle). The dissociation constant was calculated using Evaluation software.
- the aptamer candidate sequences obtained in each round (1 to 3 rounds) of conventional CE-SELEX, MB-CE-SELEX (first round), and MB-CE-SELEX (improved version) are used as next-generation sequencers. (Ion PGM system).
- the total number of read sequences per round was 90000-800000 (Table 2).
- the analysis was mainly carried out on 10 sequences having a large number of counts.
- the sequence name is T_apt. 1-10 (conventional CE-SELEX), T_beads_apt. 1 to 10 (MB-CE-SELEX), T_beads_re_apt. 1 to 10 (MB-CE-SELEX improved version).
- Binding ability of aptamer candidate sequences Table 4 shows the binding ability of each candidate sequence to thrombin calculated using a surface plasmon resonance (SPR) sensor.
- T_apt With respect to 10, although a slight increase in response was observed, the peak shape was box-shaped, that is, the dissociation was very fast, and thus the binding ability was considered to be low (FIG. 2B, K). As a control, TBA_like_apt. Having the same sequence as TBA 15 was used. When a binding experiment was conducted for 1 as well, a specific response was obtained (FIG. 2L).
- Specific responses were obtained for the four aptamer candidates (Fig. 3).
- T_beads_re_apt. 6 T_beads_apt.
- Specific responses were obtained in 8 aptamer candidates other than 9 (FIG. 4).
- a unique response curve not obtained with other aptamers was obtained.
- These two aptamers maintained a constant response after drawing a relatively fast dissociation curve (FIG. 5). In other words, it was considered that a certain number of aptamers are firmly bound to thrombin and cannot be separated.
- the ratio of the top sequences of each selection method that showed high binding capacity was 3/10 for conventional CE-SELEX, 4/10 for MB-CE-SELEX, and 8 for MB-CE-SELEX (improved version). / 10.
- the aptamer acquisition probability (sum of the counts of sequences having high binding ability / sum of the counts of sequences examined for binding ability) is calculated from the count numbers (presence) of each of the 10 upper sequences
- the conventional CE- SELEX was 23%
- MB-CE-SELEX was 83%
- MB-CE-SELEX (improved version) was 91% (FIG. 6).
- thrombin aptamers can be obtained with higher probability than conventional CE-SELEX.
- the dissociation rate constant is mainly small when the aptamer acquisition probability (sum of counts of sequences having high binding ability / sum of counts of sequences examined for binding ability) increases.
- Nucleic acid aptamer (not easily dissociated) was removed.
- T_beads_re_apt. which has binding ability such that the slope of the dissociation curve cannot be obtained.
- T_beads_re_apt. 5 or T_beads_re_apt. which was able to calculate the dissociation constant only by single kinetic analysis. 10 was obtained.
- the difference between the first MB-CE-SELEX that intentionally widens the sorting window and the MB-CE-SELEX (improved version) that narrows the sorting window is about 18 seconds. It was revealed that it contributes to the dissociation rate constant. There is a possibility that this system can be further improved by optimizing the preparative window and making the peak derived from magnetic particles sharper.
- the present invention is useful for screening nucleic acid aptamers.
Abstract
Description
本発明は、以下に関する。
[1]下記工程:
(a)固相担体上に固定した標的分子を、核酸アプタマー候補と接触させること、
(b)キャピラリー電気泳動によって、標的分子と結合した核酸アプタマー候補を分取すること、
(c)PCRによって、核酸アプタマー候補を増幅すること、
を含む、核酸アプタマーをスクリーニングするための方法;
[2]さらに、(d)増幅されたPCR産物を一本鎖化することを含む、[1]に記載の方法;
[3]固相担体が、粒子である、[1]又は[2]に記載の方法;
[4]粒子の粒径の最小値が0.05μmである、[1]~[3]のいずれか記載の方法;
[5]標的分子が、タンパク質又は低分子量化合物である、[1]~[4]のいずれか記載の方法;
[6]核酸アプタマー候補が、一本鎖DNAライブラリーである、[1]~[5]のいずれか1項記載の方法;
[7]工程(a)~(d)を最大3回反復する、[2]~[6]のいずれか記載の方法。
以下に、従来のSELEXと本発明の相違点を示す。
表面にカルボキシ基を有する磁性粒子Dynabeads MyOne(商標) Carboxylic Acid(Invitrogen)を担体として、製品に付属のプロトコールにしたがい分子の固定化を行った。20mM Tris-HCl、10mM NaCl,1mM MgCl2バッファー(pH7.4)を100μl添加し、10mg/mlの磁性粒子ストック溶液として4℃で保存した。
キャピラリー電気泳動条件
キャピラリー電気泳動システム(Agilent 7100:大塚電子)を用いた。キャピラリーは長さ80.6cm、有効長(検出窓までの長さ)72.2cmの75μm内径バブルセルフューズドシリカキャピラリー(Agilent technologies)を用いた。インレット側(注入口、陽電極側)とアウトレット側(溶出口、陰極側)の電極の間から、等しい長さのキャピラリーが出るようにキャピラリーをカセットにセットした。前処理として約1barの圧力適用により0.1M NaOH水溶液を10~20分間流した。さらに、ランニングバッファー(100mM ホウ酸バッファー、pH8.5)を10~20分間流すことでキャピラリー内を平衡化させた。
サンプルの調整
標的タンパク質のトロンビンやssDNAライブラリーは、サンプルバッファー(20mM Tris-HCl、10mM NaCl,1mM MgCl2バッファー、pH7.4)で溶解または希釈した。ssDNAライブラリーには、30merのランダム配列の両端(5’側と3’側)を20merの固定配列ではさんだ計70merの合成オリゴDNAを用いた。サンプルバッファーと100μM ssDNAライブラリーをPCRチューブに入れ、ピペッティングにより混合した。サーマルサイクラー(タカラバイオ)によってssDNAライブラリー溶液を95℃で2分間加熱した後、0.1℃毎秒の速さで25℃まで冷却することで、アニーリングをおこなった。
アニーリング後、2μMのトロンビン、あるいは5~10mg/mlトロンビン固定化磁性粒子溶液を1μl加え、30分以上室温(25℃)でインキュベートした。ターゲット・ssDNAライブラリー混合溶液は、100mbarの圧力を6~9秒間かけることでキャピラリーのインレット側から注入した。Hagen-poiseuilleの法則に基づいて以下の式からおおよその注入量を予測することができる。Vは注入量(nl)、ΔPは圧力変化(bar)、dはキャピラリー内径(m)、πは円周率、Tは注入時間(s)、ηは溶液粘度、Lはキャピラリー全長(m)を表す。
V=ΔPd4πT/128ηL×1012[nL]
50μlのランニングバッファーが入ったバイアルをインレット側(注入口、+電極側)とアウトレット側(溶出口、-電極側)それぞれにセットし、30kVの定電圧を引加して電気泳動をおこなった。電気泳動中は、ダイオードアレイ検出器によって195、260、280、550nmにおける吸光度を経時的に測定した。泳動速度は常に一定であると仮定し、以下の式から溶出時間を算出することで、分取時間を設定した。T溶出は溶出時間、T検出は検出時間、L全長はキャピラリー全長、L有効長はキャピラリー有効長を表す。
T溶出=T検出×L全長/L有効長
トロンビン固定化磁性粒子を用いた分取サンプルは、サーマルサイクラーを用いて95 ℃で10分間加熱することで磁性粒子表面のタンパク質を変性させ、ssDNAを遊離させた。マグネットスタンドに1分間静置した後、上静を回収した。
キャピラリー電気泳動によって分取したssDNAサンプルをPCRによって増幅した。1.5mlチューブに2×premixを400μl、DEPC処理水を192μl、4μMのフォワードプライマーを80μl、4μMの5’-ビオチン化リバースプライマーを80μlを入れて混合し、8つの200μlのPCRチューブに94μlずつ分注した。6つのチューブに分取サンプルを6μlずつ添加し、残りの二つのチューブにはポジティブ・ネガティブコントロールとして1~10pM ssDNAライブラリーとDEPC処理水をそれぞれ6μlずつ添加した。サーマルサイクラー(タカラバイオ)を用いて94℃で1分間加熱した後、「94℃で15秒、55℃で5秒、72℃で20秒」という操作を23~28回繰り返した。PCR終了後は、ポリアクリルアミドゲル電気泳動(PAGE)によって目的のサイズのDNAが増幅されているかどうかを調べた。電気泳動後のゲルを染色液に浸し、10分間振盪した。UV照射器によって、染色後のDNAのバンドを検出した。
PCR産物を一本鎖化し、次のラウンドで用いるssDNAライブラリーとした。ストレプトアビジン固定化磁性粒子であるmagnosphere MS300/Streptavidin(Invitrogen)を用いて、添付の説明書通りに固定化、洗浄操作を行った。調製しておいた0.1M NaOHを50μl添加し、10~15回ゆっくりとピペッティングして懸濁した後、4分間常温で静置することでアプタマー候補を遊離・抽出した。
サンプルの調製とエマルジョンPCR
エマルジョンPCR用のサンプルは付属のプロトコルに従って調製し、PAGEによって、目的のサイズのDNAが増幅されているかを確認した。その後、Fast Gene Gel/PCR Extraction Kit(日本ジェネティクス)によって、PCR産物のカラム精製をおこなった。最終的に、Ion OneTouchTM 2 system (Life Technologies)とIon PGM Template OT2 200 Kit (Life Technologies)を用いてエマルジョンPCRとビーズ精製をおこなった。参照した付属のプロトコールはPublication Number MAN0007220, Rev.5.0である。
エマルジョンPCR後の精製ビーズを用いて、Ion PGM system (Life technologies)と半導体チップIon 314 chipとIon 318 chip (Life technologies)、Ion PGM Sequencing 200 Kit v2 (Life technologies)による大規模配列解析をおこなった。操作は付属のプロトコール(Publication Number MAN0007273, Rev.3.0)にしたがった。シーケンスデータはFASTAQファイルとして出力し、CLC Genomics Workbench (CLC bio)でDNA ライブラリーのprimer領域の配列(固定配列)を除き、28~32 merのランダム配列のみを抽出した。さらに重複配列のカウント数も調べ、配列情報をexcel ファイルとして出力した。Excel (microsoft)上で配列をFASTA形式に変換し、テキストファイルとして出力した。Mafftによってアライメントをおこない、類似した配列(ファミリー配列)を抽出した。さらにMEME suite 4.11.0を用いてファミリー配列を調べた。
標的タンパク質のセンサーチップへの固定化
Biacore X100 (GE healthcare)によって、添付のマニュアルに従い、標的タンパク質のセンサー表面への固定化、ならびにアプタマーとの相互作用解析をおこなった。
ランニングバッファーにはHBS-EP(HEPES,150mM NaCl,pH7.0)を用いた。カルボキシメチルデキストラン修飾されたCM5 sensor chip (GE healthcare)を流路にセットし、10μl/minの流速でEDC/NHS溶液を7分間流し、センサーチップ上のカルボキシ基を活性化した。10mM酢酸/酢酸ナトリウムバッファー,pH6.0で希釈した10~20μg/ml トロンビン溶液を7分間流した。最後にエタノールアミンを7分間流してブロッキングをしてカップリング反応を完了させた。
アプタマー候補サンプルを、ランニングバッファーによって2~4μMに希釈した。サーマルサイクラーを用いて95℃で2分間加熱した後、0.1℃毎秒の速さで25℃まで冷却することで、アニーリングをおこなった。アニーリング後、ランニングバッファーでさらに50~200nMに希釈した。トロンビン固定化チップを流路にセットし、30μl/minの流速で希釈したアプタマー候補を流した際に、特異的なレスポンスを示すかどうかを調べた。再生溶液として、1M NaCl溶液を用いた。特異的なレスポンスが得られたアプタマー候補については、6.25~400nMの範囲で複数の希釈サンプルを調整し、マルチカイネティクス解析をおこなった。ただし、1M NaCl溶液で再生できなかったアプタマー候補については、シングルカイネティクス解析(途中に再生の工程をはさまない)をおこなった。Evaluation softwareを用いて、解離定数を算出した。
次世代シークエンサーを用いてトロンビンアプタマー候補配列を決定した手順・結果を以下に示す。
従来のCE-SELEX、MB-CE-SELEX(1回目)、MB-CE-SELEX(改良版)の各ラウンド(1~3ラウンド)で得られたアプタマー候補配列を、次世代シークエンサー(Ion PGM system)によって解析した。ラウンド毎の総リード配列数は、90000~800000であった(表2)。各選抜法で得られた3ラウンド目の配列のうち、主にカウント数が多かった10個の配列について解析を進めることにした。配列名を、T_apt.1~10(従来のCE-SELEX)、T_beads_apt.1~10(MB-CE-SELEX)、T_beads_re_apt.1~10(MB-CE-SELEX 改良版)とした。
まず、上位配列の存在率「(各配列のカウント数/総リード配列数)×100(%)」を調べたところ、各選抜法で最も濃縮されていた配列の存在率は、従来のCE-SELEXでは0.16%、MB-CE-SELEXでは12%、MB-CE-SELEX(改良版)では5.1%であった(表3)。Bowserらによって報告されたCE-SELEXを用いたVEGFアプタマーの取得に関する論文よれば、CE-SELEXで獲得されるアプタマーは多様性に富み、特定の配列の濃縮はかかり難いという仮定がなされており、実際に4ラウンド目終了時点で最も濃縮がかかった配列の存在率0.8%程度であった。本研究の結果と比較すると、従来のCE-SELEXで得られた上位配列の存在率に関しては、先行研究と同様の傾向がみられた。一方、MB-CE-SELEXによる選抜で得られた上位配列の存在率に関しては、従来のCE-SELEXで得られたものと比べて50~100倍ほど高い存在率を示しており、先行研究と比較してかなり高い濃縮効果を示していることが明らかとなった。MB-CE-SELEXでは特定の結合能をもつssDNAが濃縮されやすい条件であると考えられる。
表面プラズモン共鳴(SPR)センサー用いて算出された各候補配列のトロンビンに対する結合能を表4に示す。
上位配列のうち、トロンビンに対して高い結合能を有する配列の割合を比較することによって、新規のMB-CE-SELEXの性能を評価した。 まず、従来のCE-SELEXで得られた上位配列(計10配列)の結合能の有無を調べた(図2)。予備実験から、ssDNAライブラリーでは特異的なレスポンスの上昇が観測されなかったことから、トロンビンはssDNAと非特異的に相互作用しないということが明らかになった(図2A)。T_apt.1~10のうち、T_apt.3、T_apt.4、T_apt.6の3つのアプタマー候補において特異的なレスポンスが得られた(図2B~K)。T_apt.1、T_apt.10に関しては、わずかにレスポンスの上昇が観測されたものの、ピークの形状が箱型、すなわち解離が非常に早いことから、結合能は低いと考えられた(図2B、K)。コントロールとして、TBA 15と全く同じ配列を有するTBA_like_apt.1についても結合実験をおこなったところ、特異的なレスポンスが得られた(図2L)。
特異的なレスポンスカーブが得られた配列に関して、マルチカイネティクス解析あるいはシングルカイネティクス解析によって結合速度定数(ka)、解離速度定数(kd)、解離定数KDを算出した(図7 、表4)。T_beads_re_apt.10に関しては、解離が非常に遅いうえに高濃度のNaClでもトロンビンから解離しなかったため、シングルカイネティクス解析によって解離定数を算出した(図7J)。T_beads_re_apt.1とT_beads_re_apt.5は高い結合能を有している可能性が高いが、解離曲線の傾きがないために解離速度(kd)の算出が困難であり(図AとE)、SPRセンサーで解離定数(KD)の算出することは出来なかった。
Claims (7)
- 下記工程:
(a)固相担体上に固定した標的分子を、核酸アプタマー候補と接触させること、
(b)キャピラリー電気泳動によって、標的分子と結合した核酸アプタマー候補を分取すること、
(c)PCRによって、核酸アプタマー候補を増幅すること、
を含む、核酸アプタマーをスクリーニングするための方法。 - さらに、(d)増幅されたPCR産物を一本鎖化することを含む、請求項1に記載の方法。
- 固相担体が、粒子である、請求項1又は2に記載の方法。
- 粒子の粒径の最小値が0.05μmである、請求項1~3のいずれか1項記載のに記載の方法。
- 標的分子が、タンパク質又は低分子量化合物である、請求項1~4のいずれか1項記載の方法。
- 核酸アプタマー候補が、一本鎖DNAライブラリーである、請求項1~5のいずれか1項記載の方法。
- 工程(a)~(d)を最大3回反復する、請求項2~6のいずれか1項記載の方法。
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US20150119285A1 (en) * | 2013-10-28 | 2015-04-30 | Chin-Yih Hong | Magnetic-assisted rapid aptamer selection method for generating high affinity dna aptamer |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
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Non-Patent Citations (5)
Title |
---|
MOSING RK ET AL.: "Capillary electrophoresis- SELEX selection of aptamers with affinity for HIV-1 reverse transcriptase", ANALYTICAL CHEMISTRY, vol. 77, 2005, pages 6107 - 6112, XP003020888 * |
WAKUI K ET AL.: "Development of in vitro selection method for DNA aptamers based on the combined use of CE-SELEX and magnetic beads", CSJ: CHEMICAL SOCIETY OF JAPAN 96TH CSJ ANNUAL MEETING, vol. 96, 24 March 2016 (2016-03-24), pages Abstr. 1PB-055 - 055, XP009512736 * |
WAKUI K ET AL.: "In vitro selection of DNA aptamer by beads based capillary electrophoresis", 43RD ISNAC, 27 September 2016 (2016-09-27), pages 252 - 253, XP009513844 * |
YANG J ET AL.: "Capillary electrophoresis-SELEX selection of catalytic DNA aptamers for a small- molecule porphyrin target", ANALYTICAL CHEMISTRY, vol. 85, no. 3, 5 February 2013 (2013-02-05), pages 1525 - 1530, XP055507535 * |
YANG, J.; BOWSER, M. T.: "Capillary Electrophoresis-SELEX Selection of Catalytic DNA Aptamers for a Small-Molecule Porphyrin Target", ANAL. CHEM., vol. 85, 2013, pages 1525 - 1530 |
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WO2019146676A1 (ja) * | 2018-01-25 | 2019-08-01 | 国立大学法人 東京大学 | 核酸アプタマー |
CN110577979A (zh) * | 2018-06-08 | 2019-12-17 | 首都师范大学 | 一种基于交联反应的核酸适配体的快速筛选方法及筛选获得的结构开关型核酸适配体 |
CN110577979B (zh) * | 2018-06-08 | 2022-09-27 | 首都师范大学 | 一种基于交联反应的核酸适配体的快速筛选方法及筛选获得的结构开关型核酸适配体 |
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