日本血吸虫(中国大陆株)20.2 kDa分子编码基因(Sj20.2)的克隆及序列分析

目的：克隆日本血吸虫中国大陆株20.2kDa分子的编码基因，方法：根据筛选到的日本血吸虫肝期童虫cDNA文库阳性克隆之一的插入片段序列，设计合成1对引物，通过PCR技术对其最大开放阅读框进行扩增，然后克隆人pGEM-T载体，并对克隆产物进行核苷酸序列测定和分析，利用在线软件推测其编码氨基酸的序列，结果：利用PCR方法从上述插入片段中扩增出1条单一的DNA条带，大小介于515bp与697bp之间，将此产物克隆入pGEM-T载体，双酶切和PCR反应结果都出现与前述结果一致的目的片段，核苷酸序列测定结果表明此开放阅读框全长564bp，在线软件分析结果表明，此片段编码187个氨基酸，编码肽段分子量大小约为20．0dDa，结论：本次实验成功扩增和克隆出目的基因片段，为下一步研究奠定了基础。

CLONING AND SEQUENCING OF THE 20.2 kDa MOLECULE CODING GENE OF SCHISTOSOMA JAPONICUM CHINESE STRAIN

Objective To clone the coding gene of 20.2kDa molecule of Schistosoma japonicum Chinese strain. Methods A pair of primers P1,P2 was synthesized, based on the sequence of insert of one positive clone screened from Schistosoma japonicum Chinese strain schistosomulum cDNA li-brary. Its open reading frame was amplified by PCR and cloned into pGEM-T vector. The product was sequenced and the amino acid sequence was deduced by software online. Results A single DNA band(sized 515-697 bp)was amplified by PCR. The digestion product of recombinant plasmid by BamHI and XhoI and PCR result of cloning product showed coincidence with PCR product above. DNA sequencing showed the fragment was 564 bp, the gene was deduced encoding 187 amino acids and the MW of the peptide was about 20.2kDa. Conclusion The target fragment was amplified and cloned successfully, which will be based on in the following study.