消减杂交基因克隆技术研究进展

基因克隆技术是研究生命过程分子机制的基础,消减杂交基因克隆技术的应用,使一些多基因遗传病相关致病基因的筛查和定位有所突破。本综述近年消减杂交一基因克隆技术研究进展,包括差示反转录PCR、差异消减杂交、代表性差异分析、S1富集法、抑制性消减杂交、基因组错配扫描、比较基因组杂交及DNA微阵列杂交系统等。     

Homozygous typing cell-defined HLA-Dw specificities correlate better than serologically defined HLA-DR specificities with restriction elements for influenza virus-specific proliferative human T lymphocyte clones

Human T lymphocyte clones with specific proliferative response to influenza A virus were derived by limiting dilution from peripheral blood lymphocytes (PBL) after in vitro stimulation with autologous irradiated, virus-infected PBL. Four OKT3+4+8- T lymphocyte clones (TLC) that showed HLA-restricted antigen-specific proliferative responses were used for a detailed analysis of the restriction elements for antigen presentation. None of the clones showed alloreactivity and all required the presence on the antigen-presenting cell of HLA class II antigens of one or other haplotype of the donor. Restriction elements for two clones were correlated with Dw1 rather than DR1, and for two others with Dw6 rather than DRw6. These latter clones showed differential recognition of HLA-Dw6 subtypes as defined tentatively by homozygous typing cells, without relationship to putative serological "splits" of DRw6. One of the Dw6-restricted clones was specific for a Dw6.1 (now Dw18) "subtype," confirmed by family segregation analysis, the other for a broad Dw6 (Dw18 and Dw19) specificity. Studies with a panel of monoclonal antibodies against monomorphic determinants of HLA class II antigens revealed heterogeneous patterns of blocking activity, distinguishing between clones of different restriction specificity. Inhibition patterns were partly as predictable from the known activity of the monoclonal antibody in alloantigeneic PLT systems. These results provide evidence that certain structures that function as restriction elements for antigen presentation also carry alloantigeneic determinants.     

重组超抗原金黄色葡萄球菌肠毒素B基因的克隆和序列分析

目的　采用基因工程技术制备金黄色葡萄球菌B型肠毒素 (SEB)。方法　根据SEB已知序列 ,设计一对引物 ,用PCR方法从金黄色葡萄球菌染色体DNA上扩增出基因片段 ,克隆到原核表达质粒 pET32a上 ,转化大肠埃希菌JM10 9感受态细胞 ,经酶切和PCR鉴定 ,然后进行测序。结果　PCR扩增产物大小为 74 0bp ,重组质粒经双酶切PCR鉴定表明已正确重组 ,测序结果与已知序列基本吻合。结论　成功地克隆了金黄色葡萄球菌B型肠毒素 ,为下一步研究发病机制奠定基础。     

人白细胞介素10真核表达载体的构建及表达

目的 建立人白细胞介素10(hIL-10)真核表达系统并观察其在HeLa细胞中的表达。方法 用RT-PCR方法自活化的人外周血淋巴细胞扩增hIL-10 cDNA，将其克隆至pMDl8-T中，测序正确后，再定向插入真核表达载体pCIneo中，经脂质体介导转染HeLa细胞，检测其在细胞内外的表达和分泌。结果 RT-PCR扩增的hIL-10 cDNA序列与GenBank中hIL-10 cDNA序列一致；构建了真核重组表达载体pCIneo-hIL-10；转染HeLa细胞后可检测到hIL-10的转录和表达。结论 成功构建了hIL-10真核表达系统，为今后的临床研究及基因工程药物的生产奠定基础。     

日本血吸虫10.6 kDa膜蛋白基因的克隆及表达

目的　寻找新的预防日本血吸虫感染疫苗候选分子。　方法　用具保护性的抗血吸虫膜单抗及免疫血清筛选日本血吸虫 c DNA文库 ,PCR扩增 c DNA插入片段 ,A - T连接法将筛选获得的 3个基因片段克隆到p GEM- T载体上 ,自动测序仪测序 ,序列送 BL AST基因服务站进行同源性分析。重新设计引物扩增编号为 B8克隆的开放阅读框碱基序列 ,先将其克隆入 p GEM- T载体质粒 ,再定向亚克隆入 p BK- CMV表达质粒 ,IPTG诱导表达后用 SDS- PAGE和 Western blotting分析表达产物。　结果　经双酶切及 PCR法均证实基因重组成功。其特异性表达产物约为 10 .6 k Da蛋白抗原。表达产物可被免疫血清及单抗识别。　结论　构建了编码日本血吸虫 10 .6k Da蛋白基因表达克隆。     

Construction and identification of a recombinant live attenuated Salmonella typhimurium vaccine strain carrying Helicobacter pylori heat shock protein subunit B gene

OBJECTIVE: Because Helicobacter pylori is the principal cause of chronic active gastritis and peptic ulcer disease, the present study explored the possibility of constructing a recombinant live attenuated S. typhimurium vaccine strain carrying H. pylori heat shock protein subunit B (HspB) gene. METHODS: A 1640‐bp HspB gene was cloned into a prokaryotic expression plasmid pTrc99A. After sequence analysis, the result was compared with the sequence of H. pylori‐HspB gene and protein provided by the Genebank using BLAST analysis. The identified recombinant plasmid was then introduced into a live attenuated S. typhimurium strain SL3261. RESULTS: Using polymerase chain reaction (PCR) and restriction enzyme digestion, a recombinant pro­karyotic expression plasmid pTrc99A‐HspB harboring the HspB gene was constructed and successfully introduced into a live attenuated S. typhimurium strain SL3261. Most of the H. pylori‐HspB in the recombinant plasmid pTrc99A‐HspB was consistent with the H. pylori‐HspB sequence provided by the Genebank. The exchange of A/T or C/G in the cloned sequence hardly changed the encoded amino acids; the homology for both the genes and proteins of H. pylori SS1 strain was 97%; the homology with other common H. pylori strains J99 and 26695 was 96% for both. CONCLUSION: A recombinant live attenuated S. typhimurium vaccine strain harboring H. pylori‐HspB gene was successfully constructed and verified, which may help in the development of an oral vaccine against H. pylori infection.     

猪囊尾蚴抗原-B基因cDNA编码区的克隆

[目的 ]扩增和克隆猪带绦虫囊尾蚴 Ag B基因的 c DNA编码区。 [方法 ]提取猪囊尾蚴总 RNA中 ,利用 RT- PCR技术扩增出 Ag B基因 c DNA编码区 ,然后将其克隆到载体 p UC118中进行序列分析。 [结果 ]PCR反应产物为单一条带 ,大小为 2 .6 kb。测序结果与澳大利亚株猪囊尾蚴 Ag B序列有 99.8%的同源性 ,二者的氨基酸序列有 99.3%的同源性。 [结论 ]成功地克隆了猪囊尾蚴 Ag B基因 c DNA编码区。     

恶性疟原虫己糖转运体编码基因的体外扩增、克隆及表达

[目的 ]体外扩增、克隆和表达恶性疟原虫海南分离株的己糖转运体 (PfHT1)基因 ,为研究其保护性免疫创造条件。 [方法 ]恶性疟原虫FCC1/HN株的体外培养 ;碱裂解法提取基因组DNA ;PfHT1基因的PCR扩增、克隆 ;脂质体介导法转染HEPG2细胞株及真核表达。 [结果 ]从恶性疟原虫海南分离株基因组DNA中扩增出特异性的编码PfHT1的基因序列 ,片段大小为 15 16bp ;成功构建 pN3 HT1真核表达重组质粒并在肝癌细胞HEPG2中稳定表达。 [结论 ]体外成功扩增、克隆恶性疟原虫PfHT1编码序列 ;重组质粒转染成功并获稳定表达融合蛋白的 pN3 HT1/HEPG2细胞株     

HBV感染性克隆长度对其复制能力的影响

目的比较不同长度HBV感染性克隆复制能力的差异,为HBV复制相关研究提供依据。方法采用分子克隆的方法体外分别扩增HBV基因组的相应片段,并进行连接,分别构建含1.1、1.2、1.3倍HBV基因组的可复制性克隆。体外转染Huh7细胞系评价抗原分泌和病毒复制情况,使用高压水注射建立急性感染小鼠模型评价病毒分泌情况以及抗原在小鼠肝脏内的表达情况。结果所构建的克隆体外转染Huh-7细胞后均可分泌高浓度的HBsAg,而1.3倍HBV基因组的可复制性克隆HBeAg的分泌能力明显强于其他克隆,转录水平也最高。高压尾静脉注射小鼠后肝组织内均可检测到HBcAg的分布,血清中可以检测到HBV DNA并随时间发生动态变化。其蛋白表达水平和病毒分泌能力均以1.3倍HBV基因组的可复制性克隆较高。结论所构建的克隆在体外及体内均可进行复制,其中含HBV全基因组1.3倍体的可复制性克隆的复制能力最强,可以较好反映来源病毒株的天然复制能力。