北京地区人偏肺病毒膜表面糖蛋白G编码基因和特征的分析  

Sequence Analysis of G Glycoprotein Encoding Genes of Human Metapneumoviruses Amplified from Specimens Collected from Children with Acute Respiratory Infections in Beijing

作　　者：朱汝南[1] 钱渊[1] 赵林清[1] 邓洁[1] 王芳[1] 

机构地区：[1]首都儿科研究所病毒研究室北京感染与免疫中心实验室,北京100020

出　　处：《病毒学报》2006年第3期180-185,共6页Chinese Journal of Virology

基　　金：由国家自然科学基金(30340019);北京市自然科学基金(7052020);北京市科委新星计划(2004B34)资助

摘　　要：为了解北京地区人偏肺病毒（hMPV）膜表面糖蛋白G编码基因的特征，提取2003年和2004年各6份hMPV阳性的临床呼吸道标本中的RNA，经用随机引物合成cDNA后，用特异性引物扩增G蛋白全基因，克隆至pBST载体中并进行测序。用生物软件与GenBank中hMPV的基因序列进行比较和种系进化分析。12株hMPV可以分为两个主要的进化簇1和2。每个进化簇还可以再分为不同的亚进化簇。3株（2003年）hMPV属于进化簇1；9株（3株2003年和6株2004年）hMPV属于进化簇2。这12株hMPV G蛋白基因的核苷酸长度在624～711nt，使用了两种不同的终止密码，编码的氨基酸长度为208～236aa，蛋白质分子量为22．9～25．8kD。与进化簇2相比，进化簇1的3株hMPV都出现了3个核苷酸的缺失，但未改变读码框架。同一进化簇内的hMPV G蛋白基因核苷酸和氨基酸的同源性分别为95．7％～100％和91．8％～100％，不同进化簇间的核苷酸和氨基酸的同源性分别为56．3％～57．4％和34．3％～38．2％。疏水性分析表明这12株hMPV G蛋白是典型的Ⅱ型跨膜锚定蛋白，分别与两个进化簇代表株的疏水图一致。这些hMPV的G蛋白氨基酸的替换集中在胞外区。它们都含有高百分比的脯氨酸（P）、丝氨酸（S）和苏氨酸（T），含有相当数量的位于胞外区的O-连接糖基化化点。这些hMPV的G蛋白的N连接糖基化位点数目和位置不尽相同。通过对G蛋白基因的分析显示，2003年和2004年北京地区流行的hMPV分属于两种不同的进化簇。基因分析品示hMPV的G蛋白是高精基化的膜表面蛋白，具有与同属于副粘病毒科、肺病毒亚科的人呼吸道合胞病毒（hRSV）的G蛋白相似的基因特征，推测其功能和在感染免疫中的作用相当于hRSV的G蛋白，但有待进一步深入研究予以证实。Human metapneumovirus （hMPV） is a recently identified respiratory virus more like human respiratory syncytial virus （RSV） in clinical symptoms. The G protein, which is equivalent to the most variable gene in RSV, is the envelope glycoprotein of hMPV. For understanding the genetic diversity of the G glycoproteins of hMPVs, the genes encoding G glycoprotein of hMPVs which had already been identified in Beijing were analyzed. RNAs were extracted from clinical specimens collected from children with acute respiratory infections and showed hMPV postive by RT PCR from year 2003 to 2004 （6 clinical samples for each year）. The full length of G glycoprotein genes of the samples were amplified by RT PCR and cloned into T-vector and then sequenced. Bioinformatic softwares were employed to analyze the sequences. Results showed that phylogenetic analysis for G genes from 12 hMPVs revealed the existence of two major clusters, cluster 1 and 2. Three of the hMPVs in 2003 belong to cluster 1, and the other 3 hMPVs in 2003 and 6 hMPVs in 2004 to cluster 2. Two deduced termination codons located at different sites could be used by these 12 hMPVs. Use of alternative transcriptiontermination codons could result in variation of the length of G glycoproteins from 624 to 711 nucleotides, encoding proteins from 208 to 238 amino acids （Mr about 22.9kD to 25.8 kD）. Compared to hMPVs in cluster 2, three nucleotide deletion occurred in 3 of the G genes from hMPVs in cluster 1. Sequence identities within the same cluster ranged from 95.7% to 100% at the nucleotide level and 91.8% to 100% at the amino acid level, whereas sequence identities between the different clusters ranged from 56.3 % to 57.4 % at the nuleotide level and 34.3% to 38.2 % at the amino acid level. Hydrophobic analysis of these 12 hMPVs showed a pattern consistent with an anchored type Ⅱ transmembrane protein as well as that of the representatives of the two clusters. Most of the substituted amino acids in these hMPVs located at the extracellular domains. The

关 键 词：人偏肺病毒 膜表面糖蛋白G 基因特征 

分 类 号：R373.1[医药卫生—病原生物学]