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【目的】研究引起新生儿晚期黄疸的人巨细胞病毒(cytomega lovirus,HCMV)UL144基因的多态性,探讨HCMV UL144基因多态性与致病性之间的关系。【方法】应用荧光定量PCR法检测本院新生儿科2008年1—12月98例晚期黄疸新生儿样本HCMV-DNA含量,采用巢式聚合酶链反应扩增阳性标本HCMV UL144基因开放读码框(ORF),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】1)30例晚期黄疸新生儿HCMV荧光定量PCR检测阳性,阳性率30.6%,其中2例UL144基因扩增阴性。2)28株UL144基因与Toledo株进行同源性比较,核苷酸水平为80.4%~99.2%,氨基酸水平为78.9%~98.8%。种系进化树分析将DNA序列分为3个基因型,其中G1型7株(25%),G2型7株(25%),G3型14株(50%)。3)ExPASy数据库预测分析UL144基因编码产物重要功能区包括2个半胱氨酸富集结构域(CRD1、CRD2)、1个跨膜区和1个胞浆区。G1-G3型蛋白质二级结构高变区主要分布在CRD1区,跨膜区和胞浆区结构高度保守。【结论】1)HCMV感染是导致新生儿晚期黄疸的原因之一;2)HCMV UL144基因编码跨膜区和胞浆区结构高度保守,CRD1呈高度多态性;3)晚期黄疸新生儿中HCMV感染以G3型为主。
【Objective】 To investigate the polymorphism of UL144 gene in cytomegal lovirus (HCMV) caused by neonatal jaundice and to explore the relationship between HCMV UL144 gene polymorphism and pathogenicity. 【Method】 The HCMV-DNA content of 98 cases of neonatal jaundice from January to December in 2008 in our hospital was detected by real-time PCR. The nested polymerase chain reaction was used to amplify the HCMV UL144 open reading frame ORF), the results of two-way DNA sequencing, sequence analysis by BioEdit, DNAstar, GeneDoc and other software. [Results] 1) 30 cases of neonatal jaundice HCMV fluorescence quantitative PCR positive, the positive rate was 30.6%, of which 2 cases of UL144 gene amplification negative. 2) The homology comparison of 28 UL144 genes with Toledo showed that the nucleotide level was 80.4% -99.2% and the amino acid level was 78.9% -98.8%. Phylogenetic tree analysis divided the DNA sequences into three genotypes: 7 (25%) for G1, 7 (25%) for G2, and 14 (50%) for G3. 3) ExPASy Database Prediction and Analysis The important functional regions of the gene encoding UL144 gene include two cysteine-rich domains (CRD1 and CRD2), one transmembrane region and one cytoplasmic domain. The hypervariable regions of the G1-G3 protein secondary structure are mainly distributed in the CRD1 region, and the structures of the transmembrane and cytoplasmic regions are highly conserved. 【Conclusion】 1) HCMV infection is one of the reasons leading to neonatal jaundice. 2) HCMV UL144 gene is highly conserved in transmembrane and cytoplasmic domains and highly polymorphic in CRD1; 3) HCMV in neonates with advanced jaundice G3-based infection.