传染性支气管炎病毒嗜腺胃毒株(ZJ971毒株)结构蛋白和S1基因的结构分析

Structural Analysis of the S1 Gene of Proventriculus pathogenic Infectious Bronchitis Virus (ZJ971 Isolate) and Its Structural Proteins

对来自浙江地区的传染性支气管炎病毒嗜腺胃毒株 ( ZJ971株 )的结构蛋白进行了 SDS电泳分析 ,用RT-PCR扩增其 S1基因 c DNA,并作了测序分析。结果显示 ,ZJ971株结构蛋白由 2 1 2 0 0 0、1 4 60 0 0、974 0 0等 8条蛋白带组成 ,与其他传染性支气管炎病毒株相比缺损 1 1 60 0 0蛋白条带 ;S1基因全长为 1 72 0 nt,编码 1条 551个氨基酸组成的多肽 ,其核苷酸与其他传染性支气管炎病毒株的同源性为 99.4 0 %～ 77.85%。ZJ971株不同于其他血清型传染性支气管炎病毒的最显著特征为 :S1基因 1 2 5、1 82、2 77位上的碱基被置换 ,缺失 Fok 、Bb V 、Pflm 、Fnu4 H 4个核酸内切酶位点 ;S1蛋白多肽链 4 1、59、91、1 4 1位点上的氨基酸被置换 ,并在二级结构上出现 4 0～ 50位氨基酸区域的亲水性下降、1 4 0～ 1

There were 8 protein bands at 212 000, 146 000, 97 400, 84 000, 77 500, 60 400,54 900 and 43 000 from infectious bronchitis virus(IBV) strain ZJ971 according to the results by SDS PAGE. The isolate showed no the band at 116 000 as compared with other IBVs. Western blotting analysis indicated that the band at 54 900 in IBV ZJ971 strain reacted specifically with the monoclonal antibody against the IBV nucleoprotein. The S1 gene segement with 1.7 kb in length was amplified and cloned by RT PCR from the viral strain of IBV ZJ971. The cloned S1 gene from IBV ZJ971 was 1720 bp in length encoding for 551 amino acids. Gene sequence analysis by the PC/GENE software revealed that IPV ZJ971 isolate did not have digestion sites for FokⅠ, BbvⅠ, PflmⅠ and Fnu4HⅠ in comparison with other IBV isolates of different serotypes. the nucleotide homogeneity between IPV ZJ971 isolate and IBV of different serotypes ranged from 77.85% to 99.40%. The nucleic acid T, G and C (or T) at the sites 125, 128 and 277 were substituted by G, A and G. The amino acids at sites 41, 59, 91 and 141 were mutated as Trp, Asp, Asp, and Ser. Such mutations resulted in conformational changes in the secondary structure of S1 glycoprotein of IBV ZJ971 strain with reduced hydrophilicity at the site between 40 50 and increased hydrophilicity at the site between 140 150. These findings provided the evidence for the first time on the difference between IBV ZJ971 strain and other IBVs at protein and molecule level.