日本血吸虫肌动蛋白轻链基因的获得和分析

目的运用表达序列标签(expressedsequencetag,EST)技术,从日本血吸虫成虫cDNA文库中筛选和鉴定日本血吸虫新基因,为寻找日本血吸虫新的候选疫苗奠定基础。方法转化日本血吸虫成虫cDNA文库,随机挑取重组阳性克隆进行测序,获得EST;用NCBI站点的GenBank对所获得的新基因序列进行同源性检索;利用BLAST程序对同源性高的基因进行核苷酸和氨基酸水平的同源性比较;并利用pcgene软件对其蛋白质结构进行初步分析。结果发现xzw00081克隆的cDNA序列为日本血吸虫新基因并获得GenBank登录号(AY225851)。该cDNA序列与曼氏血吸虫肌动蛋白轻链基因高度同源,核苷酸水平的同源性为84%;氨基酸水平的同源性为86%;编码蛋白的理论相对分子质量为1053888,等电点为696;抗原表位可能位于氨基酸序列158～184处。结论用EST寻找日本血吸虫新基因是一种可行的方法,所筛选到的日本血吸虫新基因长374bp,编码88个氨基酸,与曼氏血吸虫肌动蛋白轻链基因高度同源,为进一步研究该基因的全序列及功能作准备。

Screening and identification of a novel gene encoding for the dynein light chain in adult worms of Schistosoma japonicum

By using the expressed sequence tag (EST) technique, a novel gene encoding for the dynein light chain in adult worms of Schistosoma japonicum was screened and identified from the cDNA library for these worms.The homology identity of this new gene was determined by GenBank of NCB1 blast programmer, and the homology of the top sequence with a high identity was compared on the nucleotide and amino acid levels with the blast programmer. The analysis of proteins was carried out by means of the pcgene software. It was found that the cDNA sequence of the xzw00081 clone was a new gene of S.japonicum with the accession number of sequence AY225851 in GenBank. And this cDNA sequence was highly homologous to the known dynein light chain genes of S.mansoni with the identity in nucleotide sequences of 84% and the identity in amino acid sequences of 86%. The academic molecular weight was 10538.88; pI was 6.96 and the antigenic epitopes was probably located on the amino acid sequence from 158 184 position. It is concluded that EST technique is an effective method to discover new gene of S.japonicum, and the novel gene screened appears to be 374 bp in length; encodes for 88 amino acid residues and shows high homology to the dynein light chain gene of S.mansoni.