旋毛虫新生幼虫期特异性T668全长cDNA的克隆及序列分析

Cloning and Analysis of a Newborn Stage Specific cDNA of Trichinella Spiralis

利用旋毛虫新生幼虫期特异性 c DNA片段 T6 6 8- SS2作为核酸探针 ,在新生幼虫 c DNA文库中筛选出 10个阳性克隆。序列测定及分子生物学软件分析表明 ,克隆 G10 - 6的 c DNA片段全长 16 0 0 bp,含 12 90 bp的开放阅读框架 ,编码 1个由 4 30个氨基酸残基组成的多肽 ,其相对分子质量理论推导值为 4 6 84 0 ,等电点 (PI)为 9.6 5。主导氨基酸为Ser(11.39% )和 Thr(10 .93% )。开放阅读框架中具有丝氨酸蛋白酶保守功能区及酶活性位点结构 ,其 N末端的信号肽及 2个糖基化位点表明 ,其为分泌性糖蛋白 ,预示其可能在细胞外起着重要作用。DNA同源性分析表明 ,该 c DNA为一新的 c DNA分子。

The newborn larvae (NBL) cDNA library of Trichinella spiralis was screened by a stage specific probe, which was isolated from NBL subtractive cDNA library. The positive clone contains a cDNA of 1 600 bp in length with an open reading frame(OFR) of 1 290 bp. The cDNA encodes a peptide of 430 amino acid residues. The signal peptide sequence in the N terminal and two glycosylation sites indicate the protein has a potential extracellular function .The search of DNA in Blastn database shows no homology to any known gene. This study laid the foundation for the further identification of its function and antigenitic.