人B组轮状病毒vp7基因的克隆和序列分析

Structural Protein vp7 Gene Sequence Analysis of Human Group B Rotavirus Strain WH-2

利用逆转录-聚合酶链反应(RT-PCR)技术,扩增了人B组轮状病毒WH-2vp7基因,连接到克隆载体pUCm-T,并对其基因序列进行了分析。WH-2与ADRV的同源性达98％,与印度加尔各达分离株CAL-1达92％,而与动物B组轮状病毒同源性差别较大,如与IDIR(鼠)同源性仅为58％,与WD653(牛)B组轮状病毒同源性为63％,与ATI(牛)同源性为61％。对vp7基因的二级结构分析发现其mRNA折叠形成多达18个发卡环状结构。VP7蛋白是249个氨基酸组成,分子量为28.4kDa,含有3个潜在的N连接的糖基化位点和多个磷酰化位点,从氨基酸序列的同源性来看,WH-2与ADRV的同源性达99％,与CAL-1达95％,而IDIR仅为51％,说明了WH-2和ADRV的起源相同。此研究对了解B组轮状病毒基因的进化和变异规律具有重要意义,也将为B组轮状病毒预防性疫苗的研制提供科学的依据。

The VP7 gene (vp7) of Human group B rotavirus (GBRV) strain WH-2 was amplified and cloned into the plasmid pUCm-T by reverse transcription polymerase chain reaction(RT-PCR). Positive vp7 gene cloned plasmid pT-VP7 was sequenced and analyzed by software GeneBee, the nucleotide sequence of WH-2 vp7 gene showed high identities (more than 90%) to that of other human GBRV, with low identities (less than 65%) to that of animal GBRV. The secondary structure of WH-2 vp7 mRNA was constructed by software RNAstructure 3.7 and RnaViz 2.0, 18 stem-loop structures were found on it. The polypeptide encoded by WH-2 vp7 gene contains 249 amino acids with a calculated molecular weight of 28.4 kDa. The protein contains three potential N-linked glycosylation sites and a hydrophobic signal-liked sequence at its amino terminal. Comparied with other GBRV, WH-2 vp7 demonstrated 99% and 95% of amino acids similarity with ADRV and CAL-1 respectively, only 51% with IDIR. These findings suggested that WH-2 and ADRV might originate from a common ancestral virus, district from animal WH-2 vp7 reported so far.