晚期黄疸新生儿人巨细胞病毒感染与US3基因多态性的关系

目的了解晚期黄疸新生儿人巨细胞病毒（HCMV）感染状况,探讨HCMV US3基因多态性与致病性之间的关系。方法应用巢式PCR法检测2010年1～6月在本院新生儿科就诊的79例晚期黄疸新生儿样本HCMV US3基因,阳性标本结果进行双向DNA测序,通过BioEdit、DNAstar、GeneDoc等软件进行序列分析。结果 79例晚期黄疸新生儿中20例HCMV US3基因PCR扩增阳性,阳性率25.3%。以Towne作为参考株,序列比对分析显示,20株临床分离株US3的ORF长度均与参考株相同,为561bp,编码186个氨基酸蛋白。US3核酸变异比较普遍,变异主要集中在序列的N端,大部分是同义突变,US3氨基酸序列高度保守,仅几个位点在少数分离株中存在变异。未发现US3基因多态性与临床致病性的联系。结论 HCMV感染是导致新生儿晚期黄疸的重要原因之一。20株临床分离株HCMV US3基因编码的氨基酸序列比较保守,但仍存在一定的多态性。未发现不同临床分离株US3基因多态性与HCMV引起的新生儿晚期黄疸的联系。

Genetic variations of US3 genes of human cytomegalovirus strains collected from late jaundice infants

Objective To investigate the human cytomegalovirus（HCMV） infection in infants with late jaundice and to explore the relationship between US3 gene polymorphism and the development of late jaundice.Methods PCR was used to amplify the entire HCMV-US3 gene region of clinical strains collected from late jaundice infants.The PCR products were sequenced and phylogenetic analysis was conducted using BioEdit,DNAstar,GeneDoc.Results 20 out of 79 isolates were successfully amplified and the positive rate of detection was 25.3%.By comparing with Towne sequence,the length（561 bp） of US3 ORF in all 20 clinical isolates was similar to that of reference isolate.Mutations were mainly sense mutation and the mutations were mainly found at the N-terminal of the US3 gene.The amino acid sequence of the US3 proteins was highly conserved although several strains had variation.Phylogenetic tree analysis did not show any clear association between the pathogenesis and the distribution of clinical isolates.Conclusion HCMV infection is the major cause of late jaundice in newborns.The DNA and the deduced amino acid sequences of US3 gene shared similarity among HCMV clinical strains regardless of their polymorphism.No linkage was found between the diversity of US3 gene and the development of late jaundice.