PCR在消减文库构建中的应用

目的：消减文库构建过程中，用PCR技术快速筛选重组阳性克隆。方法：将白色单菌落加入氯苄抗性LB培养液中，37℃摇振培养过夜，取细菌悬液作PCR模板。结果和结论：以PCR方法筛查重组阳性克隆，可以简便快速鉴定重组阳性克隆，不需提取质粒。筛选重组阳性克隆可直接用细胞悬液作PCR模板，在消减文库构建时，能大大提高工作效率。     

慢性肾炎肾阴虚证cDNA消减文库的构建

目的:采用抑制性消减杂交(SSH)技术构建汉族人慢性肾炎(CGN)肾阴虚证cDNA消减文库。方法:选择汉族人CGN且中医辨证为肾阴虚证的患者以及正常人作为其对照组,进行正向和反向消减杂交。采用Trizol一步法提取总RNA,用SMART技术逆转录并扩增总cDNA,用RsaI酶切基因组cDNA成大小不等的片断,分别与两种不同的接头连接,进行2次消减杂交及2次抑制性PCR,将PCR产物与U载体连接,经蓝白斑筛选后,再用PCR方法插入片段筛选出阳性重组质粒,构建CGN肾阴虚证消减文库。结果:用SSH方法筛选出了CGN肾阴虚证的差异cDNA片段,得到了386个白色克隆,再经PCR方法快速筛选出阳性重组质粒,从而成功地构建了CGN肾阴虚证的cDNA消减文库。结论:SSH技术能够快速有效地分离差异cDNA片段以构建CGN肾阴虚证cDNA消减文库,为进一步筛选和克隆CGN肾阴虚证相关基因奠定了基础。     

食管癌消减cDNA文库的构建

目的 :采用消减抑制杂交技术 ,研究正常食管粘膜和食管癌组织之间的基因表达差异状况 ,分离食管癌相关基因片段 ,构建食管癌的消减cDNA文库。方法 :以食管癌癌组织为测试子 (tester) ,以正常食管粘膜组织为驱赶子 (driver) ,用消减抑制杂交方法分离食管癌差异表达片段。将该差异表达片段克隆至T载体 ,经蓝白斑筛选后 ,再用PCR方法插入片段筛选出阳性重组质粒 ,构建食管癌消减cDNA文库。结果 :用消减抑制杂交技术分离食管癌差异表达片段 ,经蓝白斑筛选 ,得到 2 2 0个白色克隆 ;再用PCR方法快速筛选出 10 0个两端分别含连接子Adaptor1及Adaptor2R的阳性重组质粒 10 0个 ,从而成功地构建了中国人食管癌特异的消减cDNA文库。结论 :构建了中国人食管癌特异的消减cDNA文库。消减抑制杂交技术能快速有效地分离差异表达基因 ,方法简便、灵敏度高。使用PCR法快速筛选阳性克隆 ,对于消减文库的构建具有重要意义     

IgA肾病肾阴虚证cDNA文库的构建

目的应用抑制性消减杂交(suppression subtractive hybridization,SSH)技术构建汉族人IgA肾病肾阴虚证cDNA消减文库。方法选择IgA肾病且中医辨证为肾阴虚证的患者以及正常人作为其对照组,进行正向和反向消减杂交。采用TrizolBD法提取总RNA,用SMART技术逆转录并扩增总cDNA,用RsaⅠ酶切基因组cDNA成大小不等的片段,分别与两种不同的接头连接,进行2次消减杂交及2次抑制性PCR,然后将PCR产物与U载体连接,经蓝白斑筛选后,再用PCR方法插入片段筛选出阳性重组质粒,构建IgA肾病肾阴虚证消减文库。结果用SSH方法筛选出了IgA肾病肾阴虚证的差异cDNA片段,其中正向消减文库共获得325个阳性克隆,反向消减文库获得306个阳性克隆,从而成功地构建了IgA肾病肾阴虚证的cDNA消减文库。结论SSH技术能够快速有效地分离差异cDNA片段,成功构建了IgA肾病肾阴虚证的cDNA文库,为进一步克隆肾阴虚证的相关基因奠定了基础。     

肾阴虚证cDNA文库的构建

目的探讨肾阴虚证的相关基因。方法以辨病与辨证相结合，从糖尿病、慢性肾炎、狼疮性肾病以及亚健康状态等肾阴虚证入手，应用RNA微量扩增、抑制性消减杂交、基因克隆等技术和方法。分别构建肾阴虚证的cDNA子消减文库，再运用核酸分子杂交原理和PCR进一步筛选上述消减文库中的相同部分．以构建肾阴虚证的共同文库，然后将PCR产物与U载体连接，经蓝白斑筛选后，再用PCR方法插入片段筛选出阳性重组质粒。结果该研究成功地构建了肾阴虚证的cDNA文库，其中正向消减文库共获得625个阳性克隆，反向消减文库获得736个阳性克隆。结论该研究初步构建了肾阴虚证的cDNA文库，为进一步克隆肾阴虚证的相关基因奠定了基础。     

食管癌消减cDNA文库的构建

目的：采用消减抑制杂交技术,研究正常食管粘膜和食管癌组织之间的基因表达差异状况,分离食管癌相关基因片段,构建食管癌的消减cDNA文库。方法：以食管癌组织为测试子（tester),以正常食管粘膜组织为驱赶子（driver),用消减抑制杂交方法分离食管癌差异表达片段。将该差异表达片段克隆至T载体,经蓝白斑筛选后,再用PCR方法插入片段筛选出阳性重组质粒,构建食管消减cDNA文库。结果：用消减抑制杂交技术分离食管癌差异表达片段,经蓝白斑筛选,得到220个白色克隆;再用PCR方法快速筛选出100个两分别含连接子Adaptor1及Adaptor2R 的阳性重组质粒100个,从而成功地构建了中国人食管癌特异的消减cDNA文库。结论：构建了中国人食管癌特异的消减cDNA文库。消减抑制杂交技术能快速有效地分离差异表达基因,方法简便、灵敏度高。使用PCR法快速筛选阳性克隆,对于消减文库的构建具有重要意义。     

正加速度重复暴露大鼠脑差异表达基因的筛选

目的 筛选大鼠经正加速度(Gosiliveacceleration， Gz)重复暴露后脑的差异表达基因，探讨 Gz重复暴露致脑损伤的分子机制。方法 应用抑制性消减杂交技术，构建高消减效率的 Gz重复暴露大鼠脑cDNA消减文库；用差异筛选技术筛选阳性克隆；用序列分析确定阳性克隆的性质；用RT—PCR证实阳性克隆的可靠性。结果 从消减库中获得70个阳性克隆；经差异筛选后，选取其中10个阳性克隆，序列分析表明，7个克隆与已知基因高度同源，3个为新的候选基因。RT—PCR证实了差异表达基因在 Gz重复暴露大鼠脑中高表达。结论 用抑制性消减杂交技术筛选发现的3个新的cDNA可能在 Gz脑损伤的病理过程中起重要作用。     

高胆固醇血症小鼠相关基因消减文库的建立

目的 构建高胆固醇血症小鼠cDNA消减文库.方法 以高胆固醇血症小鼠肝组织的eDNA为Teste,以正常小鼠肝组织的cDNA为Driver,应用抑制消减杂交技术(Suppression subtractive hybridization).构建正向消减文库,反之构建反向消减文库.结果 成功构建高胆固醇血症cDNA正.反向消减文库,利用葛落PCR技术鉴定文库的阳性克隆.结论 用SSH技术成功构建了高胆固醇血症小鼠差异表达基因消减cDNA文库,该消减cDNA文库的建立为进一步筛选.克隆高胆固醇血症小鼠差异表达的基因奠定了基础.     

高凝状态大鼠肝脏差异表达基因正向消减cDNA文库的构建与初筛

目的构建高凝状态(prothrom botic states,PTS)大鼠肝脏差异表达基因正向消减cDNA文库并进行初步筛选。方法从PTS模型大鼠和对照大鼠肝脏提取po ly A mRNA,分别以po ly A mRNA为模板,依次合成单链和双链cDNA,经酶切成400~600 bp大小的片段。以PTS大鼠cDNA作为T ester,对照大鼠cDNA为D river,进行抑制性消减杂交。将消减杂交第二次PCR产物cDNA克隆至pM D 18-T载体上,然后转化细菌,获得PTS大鼠肝脏差异表达基因正向消减cDNA文库。用巢式PCR扩增法制备“正向”和“反向”消减cDNA探针;采用差异筛选方法,用这两种探针对PTS大鼠肝脏差异表达基因正向消减cDNA文库进行筛选;将获得的阳性克隆cDNA进行序列分析;并与G enB ank DNA数据库中的DNA序列进行同源性分析。结果成功构建了PTS大鼠肝脏差异表达基因正向消减cDNA文库,初步筛选发现两条PTS差异表达cDNA片段。结论成功构建了PTS大鼠肝脏差异表达基因正向消减cDNA文库。     

应用抑制消减杂交技术构建哮喘病人嗜酸细胞差异表达基因消减cDNA文库

目的构建哮喘病人治疗前后嗜酸细胞差异表达基因的消减cDNA文库。方法采用新近建立的抑制消减杂交方法，哮喘治疗前后的嗜酸细胞为试验和对比材料，分离哮喘病人嗜酸细胞中差异表达基因的cDNA片段，将其与T载体进行T／A连接构建文库，将连接产物用氯化钙转化法转化大肠杆菌进行文库扩增和蓝白斑筛选，随机挑取100个白色克隆用菌落PCR进行鉴定。结果扩增消减cDNA文库获得3000余个白色阳性克隆，随机挑取100个白色克隆用PCR进行扩增，90％的克隆中均有200～600bp的插入片段，这些片段可能是哮喘嗜酸细胞差异表达基因的cDNA片段。结论用SSH法及T／A克隆技术成功构建了哮喘病人治疗前后嗜酸细胞差异表达基因消减cDNA文库，该消减cDNA文库的建立为进一步筛选、克隆哮喘病人嗜酸细胞差异表达的新基因奠定了基础。     

采用消减杂交初步筛选先兆子痫病理相关基因

目的 应用抑制性消减杂交、PCR技术，克隆出与先兆子痫有关的高表达基因和(或)新基因。方法 分别从正常妊娠分娩胎盘和先兆子痫患者分娩胎盘中提取mRNA，采用抑制性消减杂交、PCR技术，构建先兆子痫胎盘cDNA文库，采用反向杂交验证，测序分析；以初步筛选的差异表达基因为探针，与先兆子痫和正常胎盘总体mRNA斑点杂交。结果 构建成功具有高消减效率的与先兆子痫相关cDNA消减文库，文库扩增后得到60个阳性克隆，经杂交验证，有34个阳性克隆有插入片断，随机挑取一阳性克隆菌落，测序分析发现该差异表达基因为核蛋白多糖基因，以该差异表达基因为探针，与先兆子痫和正常胎盘总体mRNA斑点杂交，观察其在总体胎盘中的表达。结论 人类先兆子痫胎盘基因表达同正常胎盘相比，核蛋白多糖呈差异表达基因，该基因差异表达可能与先兆子痫的发病有关．     

Suppression subtractive hybridization for identifying differentially expressed genes in renal cell carcinoma

Objective To construct a renal cell carcinoma (RCC) cDNA subtractive library using suppres sion subtractive hybridization.Methods Polyadenylated RNA ［Poly (A)(+) RNA］ was isolated from tissues of RCC and norm al kidney, and single- strand cDNAs and double-strand cDNAs were synthesized in turn. RCC cDNAs were divided into two groups and ligated to the specific adaptors l and 2, and then h ybridized with normal kidney cDNA twice with two rounds of suppression PCR. Sec ond round PCR products were cloned to T/A plasmid vectors to set up the subtract ive library. One hundred clones were randomly picked to perform enzyme digest a nalysis, and some underwent sequence analysis and Northern blot to identify RCC specifically expressed genes. SMART RACE procedure was operated to clone full l ength novel RCC specifically expressed genes.Results A human RCC subtractive library with high subtractive efficiency was successfull y set up. The amplified library contains 350 positive clones. Random analysis of 100 clones with enzyme restriction showed that 85 plasmids in the clones cont ained 50-400 bp inserts. Sequence analysis was performed for 10 clones. All t he 10 sequences were unknown before and derived from 6 unique, novel genes among which the cDNA insert RCC18 had five copies. Northern blot analysis showed tha t RCC18 cDNA was highly expressed in RCC, but no signal could be detected in nor mal kidney. Using SMART RACE technique, we obtained the full length of the nove l gene RCC18.Conclusions The constructed cDNA subtractive library of human RCC is a highly efficient one and lays a solid foundation for large scale screening and cloning new and speci fic oncogenes or tumor suppressor genes of RCC. The novel specifically expresse d genes provided an important clue for studying the mechanisms of occurrence and development of RCC.     

人LIGHT基因的克隆及其在293T细胞中的表达

目的克隆人LIGHT分子的全长cDNA,构建重组真核表达质粒pCI-neo-LIGHT并在293T细胞上获得稳定表达.方法从人T细胞cDNA文库中用PCR技术克隆人LIGHT全长cDNA,装入T-Easy载体,测序证实后,将LIGHT cDNA装入质粒pCl-neo中构建真核表达载体.用电穿孔法转染293T细胞,经G418筛选后,用流式细胞仪检测LIGHT分子的表达.结果测序证实克隆的LIGHT全长cDNA阅读框正确完整,酶切证实LIGHT-pCI-neo中LIGHT插入方向正确.转染的293T细胞经G418筛选3个月后,流式细胞仪检测有78.69%的细胞表达人LIGHT分子.结论成功克隆LIGHT基因并获得稳定表达膜型LIGHT分子的293T细胞系.     

Identification of differentially expressed genes in anagen dermal papilla by suppression subtractive hybridization

Background We constructed a cDNA subtractive library of dermal papilla cells (DPCs) in anagen with suppression subtractive hybridization (SSH) technique and clone differentially expressed genes related to DPCs in anagen. Methods Total mRNA was isolated from DPCs of anagen and telogen follicles. Moreover, singlestrand (ss) and double-strand (ds) cDNAs were synthesized in turn using SMART PCR cDNA synthesis technology, ds cDNAs then were digested with Rsa I and divided into two groups, and ligated to the specific adaptor 1 and adaptor 2R, respectively. After cDNAs were hybridized with each other twice and underwent two rounds of nested PCR. PCR products were ligated with arms of T/A plasmid vectors to set up the subtractive library. Selected clones were demonstrated by reverse Northern blot and sequenced. The acquired sequence data were aligned against the Genbank nucleotide database. Results cDNA subtractive library of DPCs in anagen follicles was set up successfully with high subtractive efficiency, Thirty-five genes were identified in this study with 22 known functional genesand 13 unknown functional genes. Conclusions All results confirm the effectiveness and sensitivity of SSH in detecting differentially expressed genes from a small amount of clinical samples. Information about such alterations in gene expression could be useful for elucidating the genetic events in hair follicle growth regulation.     

Cloning the full-length cDNA of a gene responsible for vascular smooth muscle cell proliferation in atherogenesis and study of function

Objective To clone the full-length cDNA of a gene responsible for vascular smooth muscle cell(v-SMC)proliferation in atherogenesis,and study its function.Methods Oxidized low density lipoprotein(ox-LDL)at optimal concentration was used as the stimulant to induce v-SMC proliferation in culture medium.A cDNA subtractive library of v-SMC proliferation specific to ox-LDL stimulation was established using subtractive hybridization technique.Methods,including blotting,Northern hybridization and gene sequencing,were used to clone new gene fragments.By using full-length cDNA screening and protein expression techniques,one full-length cDNA was cloned and its function was studied.Results One full-length cDNA was cloned.The new gene(Genbank AF 174647) expressed a 44 kDa protein,which mijht be associated with the activity of ox-LDL.Conclusion The new gene cloned may be associated with SMC proliferation in atherogenesis.     

阴道毛滴虫Rab1a基因的cDNA克隆及重组表达

目的克隆和分析阴道毛滴虫(Trichomonasvaginalis,Tv)Rab1a基因,构建Rab1a基因表达重组载体并表达其融合蛋白,以进一步探讨其功能。方法提取阴道毛滴虫基因组DNA为模板,扩增TvRab1a基因,用pQE80L载体与TvRab1acDNA克隆构建原核表达重组体并表达融合蛋白,纯化表达产物并由SDS-PAGE鉴定。结果在阴道毛滴虫cDNA文库克隆中发现了Rab1a基因,序列分析显示Rab1a基因的基因组DNA序列含有一个25bp大小的内含子。成功构建了pQE/Rab1a原核表达重组体,并表达出预期大小的重组蛋白质。结论分析表明TvRab1a基因是阴道毛滴虫Rab1鸟苷三磷酸酶同源基因,它含有一个25bp的内含子。获得了该基因的重组蛋白,将对TvRab1a基因的功能进行进一步研究。     

Screening and analysis of differentially expressed genes of dermal papillae cells with aggregative behavior

Objective: To screen and clone differentially expressed genes of dermal papillae cells (DPC) with aggregative behavior, and to explore the molecular mechanism of their aggregation. Methods: Total RNAs were extracted from DPC with and without aggregative behavior and double strand cDNAs were synthesized by using SMART cDNA synthesis, respectively.The cDNA fragments of differentially expressed genes in DPCs with aggregative behavior were isolated by suppression subtractive hybridization. Positive clones were screened by PCR method and verified by cDNA dot blot, Northern blot and then analyzed through homologous retrieving. Results: A subtractive cDNA library of DPC with aggregative behavior has been successfully constructed. The result of screening and cloniog of the library showed that, DPC with aggregative behavior could expresse genes related to homologous aggregation, proliferation and cycle control, including known genes (capping protein,paladin, vascular endothelial growth factor), hematopoietic stem/progenitor cells (HSPC) related clone ( HSPC011 and HSPC016) and a new gene. Conclusion: The construction of subtracted library of DPC lays solid foundation for screening and cloning new and specific genes related to aggregative behavior of DPC. Several genes might be cooperatively involved in the homologous aggregation, proliferation and cycle control of DPC.Among these genes, capping protein and palladin might be closely related to the aggregative behavior of dermal papilla cells, and VEGF and HSPC related clone would be responsible for the status of higher proliferation of dermal papilla cells.