人骨肉瘤9901细胞cDNA表达文库的构建和鉴定

目的:构建骨肉瘤9901细胞cDNA表达文库,为筛选骨肉瘤特异性抗原创造条件。方法:从9901细胞中提取总RNA,分离mRNA,反转录合成双链cDNA,末端削平,和EcoR I适配子连接。磷酸化EcoR I适配子5’端,过Sephacryl一S400柱除去小于400 bp的cDNA片段,与噬菌体λgt11(载体)连接,用包装蛋白体外包装后形成初级cDNA文库。取适量包装体系倍比稀释后感染E.coli Y1090,测定文库克隆数、重组率,用PCR法测定cDNA插入片段的大小。最后扩增cDNA文库。结果:建成含1.5×106个重组子的骨肉瘤9901细胞cDNA表达文库,重组率为94.3％。重组子中插入的外源片段不小于 0.5 kb,平均长约1.4 kb。结论:达到良好文库的质量标准,适合进一步筛选目的cDNA克隆。     

Gateway非放射标记法构建小鼠破骨细胞前体细胞cDNA文库

背景：作者前期研究发现一个在破骨细胞形成中起关键作用的基因,其在细胞之间相互识别及膜融合中发挥关键作用。 目的：采用Gateway的非放射标记技术构建小鼠破骨细胞早期形成细胞的cDNA基因文库,并检测文库质量。 方法：采集C57BL/6小鼠长骨骨髓,收集贴壁的骨髓单核细胞,加入巨噬细胞集落刺激因子和RANKL诱导形成破骨细胞,在巨噬细胞开始融合至形成破骨细胞的不同阶段开始收集细胞,提取总RNA,用CloneMiner TM cDNA文库构建试剂盒,采用非放射标记方法构建小鼠破骨细胞全长cDNA文库。 结果与结论：构建的小鼠骨髓巨噬细胞cDNA文库滴度为2.15×107 CFU/ mL,库容量为10.5×107 CFU,重组率为100%,重组子插入cDNA平均片段大小约为1.7 kb,范围为0.1~5.8 kb。表明非放射标记法构建同样可以构建小鼠骨髓巨噬细胞全长cDNA质粒文库,避免了放射性物质的接触,且文库质量良好。     

鸡B淋巴细胞cDNA T7噬菌体表达文库的构建与鉴定

目的:构建鸡B淋巴细胞cDNAT7噬菌体表达文库并对文库质量进行鉴定。方法:利用oligo(dT)-纤维素亲和层析从SPF雏鸡法氏囊细胞制备mRNA,合成的双链cDNA定向克隆到T7EcoR I/HindIII载体臂,包装并构建cDNA表达文库。对文库进行滴度测定和重组子测定。扩增文库并进行PCR鉴定插入序列的长度及分布。结果:文库初始滴度为5×107pfu/mL,扩增后滴度达到1.88×1010pfu/mL。插入片段平均长度1440bp,主要分布在750～2000bp之间。结论:构建的鸡B淋巴细胞cDNAT7噬菌体表达文库具有很高的质量,为进一步研究鸡B细胞发育以及传染性法氏囊病毒(IBDV)的分子致病机制奠定了实验基础。     

多头带绦虫脑多头蚴cDNA表达文库的构建及初步分析

从甘肃景泰羊源脑多头蚴原头节提取总RNA,以Oligo(dT)纤维素柱纯化mRNA,利用Lambda ZAP II XR文库构建试剂盒构建了脑多头蚴cDNA表达文库.从构建的原始文库随机挑选单个噬菌斑进行PCR,确定文库重组率和插入外源基因片段大小,鉴定文库质量.结果表明脑多头蚴cDNA表达文库的原始库容量为1.0×1...     

人大肠癌抗原基因cDNA噬菌体表达文库的构建和鉴定

目的:为获得大肠癌的特异性抗原基因,构建人大肠癌抗原基因的cDNA噬菌体表达文库.方法:从2株人大肠癌细胞CCL-187和CX-1中提取总RNA,分离纯化mRNA,并以此为模板合成第1链cDNA,用置换法合成第2链cDNA.双链cDNA经末端削平、EcoR Ⅰ接头连接、Xho Ⅰ酶切、过柱分级分离,除去＜400 bp片段.收集符合需要的cDNA片段与噬菌体ZAP Express载体连接,体外包装后获得人大肠癌抗原基因的cDNA噬菌体表达文库.结果:构建的人大肠癌抗原基因的cDNA噬菌体文库,原始库容量为2.3×109 pfμ/L,重组率97%.重组子插入cDNA片段平均大小1 kb以上.结论:成功地构建高质量的人大肠癌抗原基因的cDNA噬菌体表达文库,为大肠癌的特异性抗原筛选奠定了基础.     

藜草花粉变应原λ噬菌体cDNA表达文库的构建及初步鉴定

目的:构建藜草花粉变应原λ噬菌体cDNA表达文库,并进行初步鉴定.方法:用TRIzol试剂抽提藜草花粉总RNA并分离mRNA.以纯化的mRNA为模板,以含有Xho I内切酶位点和18 by的Poly(dT)序列的引物,用ZAP Express cDNA合成试剂盒反转录合成cDNA.将cDNA修饰、分级纯化后,获得大于400 by的cDNA片段.将带有黏性末端的双链ds cD-NA与Uni-ZAP XR载体连接,采用ZAP Express cDNA文库合成试剂盒利用λ噬菌体构建藜草花粉λ噬菌体cDNA表达文库,用包装蛋白对合成的ds cDNA进行体外包装,以包装产物感染宿主菌XL1-Blue MRF即获得cDNA表达文库.用PCR方法检测cDNA表达文库的滴度和插人片段的大小.结果:构建的藜草花粉变应原λ噬菌体表达文库的滴度为9.7×10(8)pfu/L,重组率为100%,库容量为4.85pfu.插人片段的长度平均约为1.0 kb.结论:构建的cDNA表达文库的容量及插人片段的大小合适,适用于藜草花粉变应原cDNA克隆的筛选,为制备基因重组藜草花粉变应原疫苗奠定了基础.     

金仓鼠神经管cDNA文库的建立

目的　构建金仓鼠神经管cDNA文库,以筛选与神经管发育及神经管畸形发生相关的基因。　方法 　用TRIZOLReagent提取金仓鼠神经管总RNA;用LD PCR法反转录合成双链cDNA;经蛋白酶K消化、SfiⅠ酶切、 CHROMASPIN 400柱分离去除小于500bp的片段;将cDNA与载体λTriplEX2按一定比例连接;经体外包装,建立 cDNA的噬菌体表达文库。　结果　cDNA文库容量为1.5×106pfu ml,重组率为99%,平均插入片段大于1kb。　 结论　我们初步构建的金仓鼠神经管cDNA文库为高效的cDNA文库。     

藏羚羊大脑皮质cDNA文库的构建

目的:构建藏羚羊大脑皮质组织的cDNA文库并鉴定文库质量。方法:提取藏羚羊大脑皮质组织总RNA,经oli-gotex试剂盒纯化得到mRNA。利用SMART技术,使用含有SfiIB酶切位点的oligo(dT)引物和含有SfiIA酶切位点的SMARTIV寡核苷酸在PowerScript逆转录酶作用下运用mRNA5′末端的模板转换方法合成cDNA第1链。利用LDPCR扩增cDNA,经SfiI(ⅠA和ⅠB)酶切后,通过CHROMASPIN-400柱进行分级分离去除<500bp的片段,再同经SfiI酶切的λTripIEx2载体连接,体外包装后转染到大肠杆菌XL1-Blue宿主菌中,进行文库滴度和重组率的测定,然后扩增文库并随机挑取10个噬菌斑行PCR反应鉴定插入片段大小。结果:构建的cDNA文库滴度为1.8×109pfu/L,重组率>98%,文库扩增后滴度达8×1012pfu/L,插入片段长度在750～6000bp之间,平均长度为4250bp。结论:文库具有良好的质量,为进一步筛选、克隆藏羚羊大脑皮质组织特异表达基因奠定了基础。     

虎眼万年青EST文库构建和Syntaxin基因的克隆及生物信息学分析

目的构建虎眼万年青 EST 文库,筛选相关基因并对其进行功能鉴定。方法 CTAB 法提取虎眼万年青鳞茎总 RNA,通过SMART 方法构建全长 cDNA 文库,获得库容大于3×106 cfu/ml 的均一化全长 cDNA 文库。随机挑取1440个单克隆测序,并对得到的 EST 序列进行 Blast 分析（NR、NT、Swiss-Prot 和 KEGG）以及 COG 功能分类。结果获得1398条有效 EST 序列,含有1146条单一基因,cDNA 文库平均插入片段长度在1.5 kb 以上,全长率54%,冗余率3.3%。其中两段基因都与 Syntaxin 43基因相似,同源性分别为76%和89%,根据 Blast 比对结果,推断这两个基因片段是同一个 Syntaxin 基因的5'端和3'端。据此设计引物,以虎眼万年青 cDNA 为模板,通过常规的 RT-PCR 扩增得到全长 Syntaxin 基因,将其克隆到大肠杆菌表达载体,接着导入大肠杆菌进行诱导表达,SDS-PAGE 和 Western blot 证实该基因在大肠杆菌获得表达。结论首次构建成功虎眼万年青 EST 文库;并从中筛选得到一条和 Syntaxin 具有同源性的基因,实现了 Syntaxin 蛋白在大肠杆菌中的表达,为 Syntaxin 基因功能的鉴定奠定基础。     

噬菌体呈现抗体库的构建及抗Fas—Fab抗体的研究

目的构建噬菌体抗体库,获得具有功能的抗Fas-Fab噬菌体抗体。方法以Fas重组蛋白为抗原免疫Balb/c小鼠。取其脾细胞提取mRNA,采用RT-PCR方法扩增抗体基因,构建重链和κ链基因库,用重组Fas抗原对所构建的抗体库进行4轮筛选,并以ELISA法鉴定其功能。结果获得抗体重链Fd基因和κ链基因长度约700bp。构建的重链Fd基因为3.5×106的抗体重链基因库。构建的重链和κ链基因库的容量均为3.1×106。经VCSM13感染得到噬菌体的滴度为8.9×1016cFu/L的噬菌体抗体库,含有抗体重链和κ链基因的噬菌体占27％。用重组人Fas抗原进行4轮筛选,得到100％的富集,说明Fas重组抗原富集了抗Fas-Fab噬菌体抗体,经ELISA检测均有抗Fas抗体的特异性。结论制备的可溶性抗Fas-Fab抗体具有抗Fas抗体的特异性,为进一步的研究奠定了基础。     

A human cDNA expression library in yeast enriched for open reading frames

We developed a high-throughput technique for the generation of cDNA libraries in the yeast Saccharomyces cerevisiae which enables the selection of cloned cDNA inserts containing open reading frames (ORFs). For direct screening of random-primed cDNA libraries, we have constructed a yeast shuttle/expression vector, the so-called ORF vector pYEXTSH3, which allows the enriched growth of protein expression clones. The selection system is based on the HIS3 marker gene fused to the C terminus of the cDNA insert. The cDNAs cloned in-frame result in histidine prototrophic yeast cells growing on minimal medium, whereas clones bearing the vector without insert or out-of-frame inserts should not grow on this medium. A randomly primed cDNA library from human fetal brain tissue was cloned in this novel vector, and using robot technology the selected clones were arrayed in microtiter plates and were analyzed by sequencing and for protein expression. In the constructed cDNA expression library, about 60% of clones bear an insert in the correct reading frame. In comparison to unselected libraries it was possible to increase the clones with inserts in the correct reading frame more than fourfold, from 14% to 60%. With the expression system described here, we could avoid time-consuming and costly techniques for identification of clones expressing protein by using antibody screening on high-density filters and subsequently rearraying the selected clones in a new "daughter" library. The advantage of this ORF vector is that, in a one-step screening procedure, it allows the generation of expression libraries enriched for clones with correct reading frames as sources of recombinant proteins.     

人高迁移率族蛋白B1原核表达及其高亲和噬菌体融合肽的筛选

目的 构建谷胱甘肽巯基转移酶(GST)标记的人高迁移率族蛋白B1(HMGB1)融合蛋白表达载体并在原核细胞中表达.应用噬菌体展示技术筛选HMGB1的高亲和肽.方法 用RT-PCR方法扩增HMGB1 cDNA,构建于原核表达载体pGEX4T-1并转化大肠杆菌,以异丙基-β-D-硫代半乳糖苷(IPTG)诱导GST-HMGB1蛋白表达;Ni2+-NTA和多粘菌素B亲和层析柱进行纯化重组HMGB1蛋白.以重组HMGB1蛋白为靶分子,进行4轮噬菌体展示环七肽库的筛选,从第4轮洗脱物中随机挑选20个单克隆噬菌体扩增后进行ELISA鉴定,用酶标仪测定450 nm处的吸光度值.对获得的阳性单克隆噬菌体分别进行扩增、纯化,并对DNA测序,以确定插入七肽的氨基酸序列.结果 RT-PCR扩增HMGB1 cDNA大小约648 bp,成功构建了pGEX4T-1-HMGB1重组质粒并纯化了HMGB1蛋白,其相对分子质量为65000.经过4轮筛选后,噬菌体富集了74倍(第4轮与第1轮回收量分别为5.2×108、7.0×106 pfu),随机挑取的20个噬菌体克隆中9个可与HMGB1结合,测序发现其中的6个序列一致,均为DYFVSSV.结论 筛选到1个可与HMGB1高亲和结合的噬菌体展示七肽,其对HMGB1活性的拮抗效应有待进一步阐明.     

Molecular cloning of cDNAs expressing SS-B/La protein

Using serum from a patient with Sj?gren's syndrome containing a high titer of anti-SS-B/La antibody, cDNA clones (a representative clone was called pA158) were isolated from a human fibroblast cDNA library in lambda gt11 expression vector. After subcloning of pA158 cDNA into an expression plasmid vector pEX-2, a large amount of the recombinant fusion protein with cro-beta-galactosidase (called pA158EX) was obtained in E. coli culture containing the recombinant pEX-2. Antibodies against pA158EX were purified from the patient serum by Sepharose 4B conjugated with the purified pA158EX protein. Immunofluorescent staining of HEp-2 cells with the anti-pA158EX antibodies showed a speckled nuclear staining. In immunoblot analysis, the anti-pA158EX antibodies reacted with 50 kDa protein that was compatible with SS-B/La protein. Immunoprecipitation of leukocyte lysate with the anti-pA158EX antibodies and the following RNA analysis showed that the antibody precipitated Y5 RNA. These findings indicate pA158 is a cDNA for SS-B/La protein. The purified fusion protein was used for enzyme-linked immunosorbent assay (ELISA). Optical density values of anti-SS-B positive sera were high, but those of anti-SS-B negative sera and healthy donor sera were low. In the Northern blot using human RNA and pA158 cDNA, a single band about 1.8 kb was recognized. A full-length cDNA was further obtained by screening of pcD library using pA158 cDNA as a probe.     

白纹伊蚊T7噬茵体展示cDNA文库的构建

为筛选白纹伊蚊与相关蚊媒病毒相互作用的基因,本文构建了白纹伊蚊Aedes albopictusT7噬菌体展示eDNA文库,分离与纯化白纹伊蚊mRNA,所得mRNA经反转录合成双链cDNA后,在双链cDNA末端加上定向EcoRI／HindIn接头使其两端分别带EcoRI和Hind11I黏性末端;接着用MiniColumn纯化收集300bp以上的双链cDNA片段连接于T7 Select 10—3b载体;经体外包装后,以BLT5403为受体菌构建1v7噬菌体展示cDNA文库。所建文库的库容量经测定为1．7×10’pfu／mL,扩增后文库滴度为2．5×10^（15）pfu／mL。对从原始文库中随机挑取的50个噬菌斑进行PCR鉴定,重组率为95％以上;阳性克隆片段长度分布在200～2000bp,其中有90％的插入片段大于300bp。本文所构建的白纹伊蚊T7噬菌体展示cDNA文库,满足cDNA文库的基本要求,可以用于筛选白纹伊蚊与相关蚊病毒相互作用的基因。     

The Tol2kit: a multisite gateway-based construction kit for Tol2 transposon transgenesis constructs.

Transgenesis is an important tool for assessing gene function. In zebrafish, transgenesis has suffered from three problems: the labor of building complex expression constructs using conventional subcloning; low transgenesis efficiency, leading to mosaicism in transient transgenics and infrequent germline incorporation; and difficulty in identifying germline integrations unless using a fluorescent marker transgene. The Tol2kit system uses site-specific recombination-based cloning (multisite Gateway technology) to allow quick, modular assembly of [promoter]-[coding sequence]-[3' tag] constructs in a Tol2 transposon backbone. It includes a destination vector with a cmlc2:EGFP (enhanced green fluorescent protein) transgenesis marker and a variety of widely useful entry clones, including hsp70 and beta-actin promoters; cytoplasmic, nuclear, and membrane-localized fluorescent proteins; and internal ribosome entry sequence-driven EGFP cassettes for bicistronic expression. The Tol2kit greatly facilitates zebrafish transgenesis, simplifies the sharing of clones, and enables large-scale projects testing the functions of libraries of regulatory or coding sequences.