4株SARS冠状病毒基因组5’端序列的分析与比较

Comparative Analysis of Genomic Organization of the 5' and of Four Strain SARS-associated Coronaviruses

利用5′RACE试剂盒对从中国不同地区、不同SARS患者体中分离的SARS-CoV基因组5′端序列进行RT-PCR扩增,并将扩增产物克隆至T easy vector。扩增片段的序列测定结果表明:所分离的4株SARS-CoV基因组5′端非编码区的核苷酸序列和其他国家和地区报道的序列基本一致,而且所形成二级结构也完全相同,但与已知普通冠状病毒的差别较大。同时发现在依赖于RNA的RNA聚合酶起始密码子上游-197 nt处有冠状病毒典型的转录调控核心保守序列5′-CUAAAC-3′。

The viral RNAs were isolated from the infected Vero-E6 cells, then the templates were produced by reverse transcription reaction.Two pairs of primers were used to amplify the 5'-ends of four strains of SARS-associated coronavirus(SARS-CoV)by RACE,cDNA fragments with the length of about 420 bp were amplified. The fragments were then purified and sequenced. The sequences of 5' -UTRs of SARS -CoV isolated in China were the same as those isolated in other countries and regions, such as Tor2 strain, Urbani strain, HKU-Sul0 strain, CUHK-W1 strain, SIN2500 strain and SIN2677 strain. The secondary structures formed by 5'-UTRs of all known SARS-CoV were almost identical, but significantly different from other known non-SARS coronaviruses. Sequence analysis indicated that the conserved core sequence(5'-CUAAAC-3') of transcription regulating sequence in some coronaviruses was about - 197 nt upstream from the start codon.