猪传染性胃肠炎病毒SC-Y株编码复制酶聚蛋白 ORF1的克隆及结构特征分析

应用RT-PCR方法扩增了猪传染性胃肠炎病毒SC-Y株编码复制酶聚蛋白的ORF1序列,将其进行克隆、序列测定和分析。确认SC-Y株ORF1全长20 053 nt(GenBank收录号DQ390461)。该序列包含2个ORF,其中ORF1a由12 053个核苷酸构成,可编码由4 018个氨基酸组成的多肽,ORF1b由8 036个核苷酸构成,可编码由2 678个氨基酸组成的多肽。对SC-Y与TGEV参考毒株及不同冠状病毒对应区进行序列比较,结果显示,SC-Y株与PUR46-MAD株的同源性最高,ORF1a的核苷酸同源性为99.5%,推导氨基酸同源性为99.2%,ORF1b的核苷酸及推导氨基酸同源性均为99.8%;不同冠状病毒之间ORF1b比ORF1a具有更高的保守性。

Cloning and Analysis of Replicase Polyprotein-Encoding ORF1 of Transmissible Gastroenteritis Virus SC-Y Strain

In this study,the complete sequence of the replicase polyprotein-encoding ORF1 of TGEV SC-Y strain was obtained by RT-PCR,the entire nucleotide sequence was determined(GenBank Accession No.DQ390461).Results showed that there were two partially over lapping open reading frames in replicase polyprotein-encoding ORF1 of SC-Y strain,the ORF1a contains 12 053 nucleotides encoding a polypeptide of 4 018 amino acids,the ORF1b contains 8 036 nucleotides encoding 2 678 amino acids.The sequences were compared among different TGEV strains and other coronary viruses.The results showed that the SC-Y has the highest homology with PUR46-MAD strain,the ORF1a and ORF1b nucleotide sequences had 99.5% and 99.8%,amino acid sequences had 99.2% and 99.8% respectively.The ORF1b is highly conserved among the different coronaviruses.