犬弓首蛔虫MUC-1基因的克隆及序列分析

Cloning and Sequence Analysis of the MUC-1 Gene of Toxocara canis

为研究犬弓首蛔虫(Toxocara canis,T.canis)黏蛋白1基因(Tc-MUC-1)的分子特征,该试验根据犬弓首蛔虫基因组数据库中的Tc-MUC-1基因序列设计引物,通过PCR技术克隆Tc-MUC-1全长基因,并进行多重序列比对和种系发育进化树分析.结果发现该基因全长为531 bp,编码176个氨基酸.功能结构域分析发现Tc-MUC-1蛋白包含1个由11个STSSSSA重复序列构成的Mucin结构域和2个ShKT结构域;GO分析显示具有蛋白质结合和金属离子结合功能;多重序列比对发现Tc-MUC-1与T.canis的其余4个黏蛋白(Tc-MUC-2-Tc-MUC-5)均含有2个由36个氨基酸组成的ShKT结构域;种系发育进化树分析显示Tc-MUC-1与双胃线虫(Pristionchus pacificus;GenBank No.PDM76930)和秀丽隐杆线虫(Caenorhabditis elegans;GenBank No.NP491509)进化关系较近.

To study the molecular characteristics of the muc-1 gene in Toxocara canis,the full-length coding sequencing of Tc-muc-1 was amplified using PCR amplification,multiple sequence alignment(MSA)was made and a phylogenetic tree was constructed.The results showed that the entire sequence of Tc-MUC-1 gene was 531 bp in length,encoding a protein of176 amino acids.In functional domains analysis,Tc-MUC-1 was found to contain one mucin domain consisting of11 STSSSSA repeats and two ShKT domains.Gene ontology(GO)annotations showed that Tc-MUC-1 had the molecular function of protein binding and metal ion binding.Multiple sequence alignments revealed that Tc-MUC-1 and the other four mucins(Tc-MUC-2 to Tc-MUC-5)of T.canis all contained two ShKT domains composed of 36 amino acids.Phylogenetic analysis indicated that Tc-MUC-1 shared the highest levels of amino-acid sequence similarity with Pristionchus pacificus(Pristionchus pacificus;No.PDM76930)and Caenorhabditis elegans(Caenorhabditis elegans;No.NP491509).In conclusion,this study lays a foundation for further functional researches on Tc-MUC-1.