猪源冠状病毒ORF3和ORF7的克隆及特性分析

Cloning and characterization of ORF3 and ORF7 of porcine coronavirus

参照GenBank中Purdue株全序列对TGEV(猪传染性胃肠炎病毒)TS株的ORF3和ORF7各设计1对特异性引物,经RT-PCR扩增分别获得了1 487 bp和516 bp大小的两个片段,与预期结果大小相符.TS株与CHV株、Puedue株、BW021898B株和KT2株的ORF3a核苷酸序列同源性分别为99.1%、93.0%、95.9%、94.4%,相应的氨基酸同源性分别为97.3%、87.8%、93.2%、91.8%,TS株与CHV株、Puedue株、BW021898B株和KT2株的ORF3b核苷酸序列同源性分别为99.5%、98.5%、97.0%、97.8%,相应氨基酸的同源性分别为98.4%、96.3%、94.3%、95.8%,而TS株与PRCVIA1894株的ORF3b核苷酸和氨基酸同源性分别为96.6%和93.9%.TS株ORF7没有发生缺失且和其他毒株有很高的同源性.结果表明:TGEV非结构蛋白高变区在ORF3a第192个碱基至终止密码子之间,TGEV和PRCV在编码ORF3b氨基酸的数量和RNA酶结合位点上有一定的差异.

Two （TGEV） ,ORF3 and otide sequence in the non- ORF7 struct were ural obt GenBank, with nucleotide levels for the ORF3a 99.1%,93.0 %,95. 9% and 97.3 %,87.8 %,93.2 %and 9 shared 99.5 %,98.5 %,97.0 % deduced amino acid with that of was no deletion in the TS ORF7 considered as the region of high protein genes of strain TS of transmissible gastroenteritis ained by RT--PCR using primers designed according to Purdue the length of 1 487 bp and 516 bp respectively. The homology gene between TS and CHV, Purdue, BW021898B, KT2 w 94. 4 % respectively, and that of the deduced amino acid 1.8 % correspondingly. The nucleotide homology of ORF and 97.8 % nucleotide identity and 98.4 %,96.3 %,94.3 as s found virus nucle- at the to be equence 3b gene o %and 95. was f TS 8% strains CHV, Purdue, BW021898B,KT2. The results indicated that there and it was conserved. The region from the 192 to TAA in the ORF3a was variety of TGEV,the results showed that there was differences in the number of amino acid and the RNA--binding site between the TGEV and PRCV.