人巨细胞病毒UL138～142基因在临床低传代分离株中的多态性研究

The polymorphism of human cytomegalovirus UL138-UL142 genes in low passage clinical isolates

目的 研究人巨细胞病毒 (humancytomegalovirus ,HCMV)UL138～UL14 2基因在临床低传代分离株中的多态性及其与HCMV先天感染致病性之间的关系。方法 对经荧光定量PCR方法检测HCMV DNA为阳性的临床分离株进行UL138～UL14 2基因全序列PCR扩增 ,对扩增阳性的标本进行全序列的测序及结果分析。结果 HCMV临床分离株的UL138、UL14 2ORF(openreadingframe)高度保守 ;UL139ORF呈现高度多态性 ,可被明确划分为 3个基因型 ,且核苷酸及氨基酸的变异主要集中在序列的 5′端 ;所有临床分离株的UL14 0ORF在Toledo株第 174位核苷酸处插入 1个胞嘧啶核苷酸 ,其ORF较Toledo株增加了 2 31个核苷酸 ;所有临床分离株的UL14 1ORF在Toledo株第 2 2 7位核苷酸处缺失了 1个胸腺嘧啶核苷酸 ,故形成UL14 1a及UL14 1b 2个新的ORF。HCMV临床分离株的UL14 0蛋白较Toledo株新增了ScAMP磷酸化和酪蛋白激酶Ⅱ磷酸化位点 ,其它基因编码蛋白的重要功能区域相对保守。结论 HCMV临床分离株UL139ORF的 5′端呈现高度多态性 ,而且被明确地分成 3个基因型 ,故其可能在HCMV先天感染的致病性差异方面起一定作用 ;尚未发现UL138～UL14

Objective To investigate the polymorphism of human cytomegalovirus UL138 UL142 genes in low passage clinical isolates and to find the relationship between the polymorphism and pathogenesis of congenital HCMV infection. Methods PCR was performed to amplify the entire UL138 UL142 genes region of clinical isolates, which had been proven containing detectable HCMV DNA. The PCR products in clinical isolates were sequenced directly and the sequence data were analyzed. Results HCMV UL138, UL142 ORFs in clinical isolates were highly conserved; UL139 ORF was hypervariable and was clustered into 3 major genotypes, these changes were concentrated in the 5′ half of the UL139 ORF; by comparison with that of Toledo, UL140 ORF in all clinical isolates had an insertion and their length was 231bp longer than that of Toledo; UL141 ORF in all clinical isolates had an deletion, so there were two new ORFs(UL141a and UL141b). Sulfation cAMP phosphorylation site(SPS) and Casein kinaseⅡ phosphorylation site(CKP) were two new potential functional sites of UL140 protein in clinical isolates. Conclusion The 5′ half of the UL139 ORF in clinical isolates was hypervariable and the nucleotide sequences could be classified into 3 major genotypes, so it might play an important role in the pathogenesis of congenital HCMV infection; Up to the present, no definite relation had been ascertained between some gene in UL138 UL142 region and the virulence of studied HCMV strains.