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

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

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。

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 ORFla contains 12 053 nucleotides encoding a polypeptide of 4 018 amino acids, the ORFlb 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 ORFla and ORFlb nucleotide sequences had 99.5% and 99.8%, amino acid sequences had 99.2% and 99.8% respectively. The ORFlb is highly conserved among the different coronaviruses.