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目的 研究人巨细胞病毒 (humancytomegalovirus,HCMV)UL136基因在临床低传代分离株中的多态性 ,探讨其多态性与HCMV先天性感染不同致病性之间的关系。方法 对 4 8株经荧光定量PCR方法检测HCMVDNA为阳性的临床低传代分离株进行HCMVUL136全序列PCR扩增 ,对于扩增阳性的 12株PCR产物进行UL136基因全序列测定及结果分析。结果 4 8株临床低传代分离株UL136PCR扩增 ,12株阳性 ,阳性率 2 5 % ,以HCMVToledo株作为参考株 ,进行序列比较分析表明 ,12株临床分离株UL136开放阅读框架 (openreadingframe,ORF)长度均与Toledo株相同 ,为 72 3bp ,编码2 4 1个氨基酸的蛋白。DNA序列变异均为碱基替换 ,不同临床分离株UL136基因与Toledo株进行同源性比较 ,结果在核苷酸水平为 97.7%～ 99.3% ,氨基酸水平为 96 .6 %～ 99.1%。UL136编码蛋白的氨基酸变异率为 0 .83%～ 3.3%。二级结构预测分为两种构象。大多数HCMVUL136蛋白翻译后修饰位点在所有分离株中均高度保守 ,仅几个位点在一些分离株中存在缺失或新增。Toledo株及 12株临床分离株核苷酸及氨基酸序列系统进化树分析表明 :4 5J最接近Toledo株。结论 12株临床低传代分离株HCMVUL136基因DNA及其编码产物的氨基酸序列比较保守 ,但仍存在一定多态性。未发现不同临床?
Objective To study the polymorphism of human cytomegalovirus (HCMV) UL136 gene in clinical low passage isolates and to explore the relationship between its polymorphism and different pathogenicity of congenital HCMV infection. Methods A total of 48 strains of HCMVUL136 positive isolates were detected by fluorescence quantitative polymerase chain reaction (PCR) for HCMV UL136 full-length PCR amplification. The full-length UL136 gene was sequenced and the results were analyzed. Results A total of 48 strains of clinical isolates with low passage isolates were amplified by UL136, 12 were positive and the positive rate was 25%. HCMVToledo strain was used as a reference strain. Sequence comparison analysis showed that 12 clinical isolates of UL136 open reading frame (ORF) The same length as the Toledo strain, 72 bp, encodes a protein of 241 amino acids. DNA sequence variations were base substitutions. The homology comparison between UL136 gene and Toledo strain showed that the nucleotide level was 97.7% -99.3% and the amino acid level was 96.6% -99.1%. The amino acid mutation rate of UL136 encoded protein was between 0.83% and 3.3%. Secondary structure prediction is divided into two conformations. Most of the HCMVUL136 protein posttranslational modification sites are highly conserved among all isolates, with only a few loci missing or added in some isolates. Phylogenetic analysis of the nucleotide and amino acid sequences of Toledo and 12 clinical isolates showed that 45J was the closest to Toledo strain. Conclusion The DNA sequences of the 12 strains of HCMVUL136 and their coding products are relatively conservative, but there are still some polymorphisms. Did not find a different clinical?