日本血吸虫原肌球蛋白编码基因克隆和表达

Cloning and Expression of the Gene Encoding Schistosoma japonicum Tropomyosin *

目的 克隆和表达日本血吸虫大陆株原肌球蛋白 (tropomyosin ,TM)编码基因。方法 应用RT PCR方法体外扩增日本血吸虫原肌球蛋白编码基因 ,并采用T载体对该PCR产物直接进行克隆并用于核苷酸序列的测定。将目的基因亚克隆入原核表达载体pQE30 ,以IPTG诱导重组原肌球蛋白的表达。结果 PCR扩增产物约 82 3bp ,符合预计大小 ,并成功地克隆入T载体 ,对其中一克隆pGSjcTM12的插入片段的核苷酸序列分析表明 ,该序列和推测的氨基酸序列与曼氏血吸虫原肌球蛋白基因分别有 91 1%和 98 1%的同源性。该编码基因亚克隆入原核表达载体pQE30获得高效表达 ,分子量约 32kDa,并能被日本血吸虫天然原肌球蛋白免疫血清特异识别。结论 日本血吸虫原肌球蛋白编码基因克隆和原核表达成功。

Objective To clone and express the cDNA encoding Schistosoma japonicum tropomyosin. Methods The cDNA was amplified by reverse transcription polymerase chain reaction (RT PCR). The PCR products were ligated with pGEM T vectors and then for transformations. After characterization of white clones by agarose gel electrophoresis, endonucleases digestion and PCR, some recombinant plasmids with inserts were used for sequencing. Then the gene was subcloned into prokaryotic expression vector pQE30 and expression was induced by IPTG. Results The PCR products was 823 bp judged by agarose gel electrophoresis and sequencing. A cDNA encoding S japonicum tropomyosin, except for 14 amino acids at the amino terminus and 2 at the carboxyl terminus, has been constructed and cloned successfully. The colony, designated pGSjcTM12, was sequenced and shown to be 91 1% identical at the nuclei acid level and 98.1% identical in deduced amino acid sequence to that of S mansoni tropomyosin. The gene was subcloned into pQE30 and an expressed protein of about 32 kDa was obtained.Conclusion The cloning and expression of the gene encoding S japonicum tropomyosin had been successfully made.