斜带石斑鱼神经坏死病毒基因组RNA1和RNA2序列测定及分析

根据GenBank数据库公布的鱼类神经坏死病毒(nervous necrosis virus,NNV)同源序列设计了7对特异性引物,采用RT-PCR方法扩增出目的片断,将PCR产物测序和分析.斜带石斑鱼Epinephelus coioides神经坏死病毒(orange-spotted NNV,OGNNV)基因组由两个片断(RNA1和RNA2)组成,RNA1由3 103个核苷酸组成,含有一个开放阅读框,编码982个氨基酸;RNA2由1 433个核苷酸组成,含有一个开放阅读框,编码338个氨基酸.OGNNV基因组与新加坡GGNNV(greasy grouper NNV)的基因组有高度的相似性.分析病毒的RNA2序列发现:OGNNV与DGNNV(dragon grouper NNV)、RGNNV(redspotted NNV)和GGNNV的亲缘关系很近,并且具有相同的中和位点;分析病毒的RNA1序列,发现在OGNNV的RNA1序列中同样可以找到依赖RNA的RNA聚合酶的6个模序(motif).根据同源性比较和系统进化分析,OGNNV属于RGNNV血清型的成员.

Sequences of RNA1 and RNA2 from Orange-spotted Grouper (Epinephelus coioids ) Nervous Necrosis Virus, China Strain

Severn pairs of specific primers are designed according to the published homogeneous sequences of nervous necrosis virus (NNV)from GenBank. The target segments are cloned by means of RT_PCR. The nucleotide sequences of RNA1 and RNA2 from OGNNV, China strain, are determined. OGNNV RNA1 is 3 103 bp long, containing an ORF of 982 aa, while OGNNV RNA2 is composed of 1 433 bp, containing an ORF of 338 aa. Both OGNNV RNAs show high similarity with those from greasy grouper nervous necrosis (GGNNV), Singapore strain. Analysis of OGNNV RNA2 reveals that it is much closely related to dragon grouper nervous necrosis virus (DGNNV), redspotted grouper nervous necrosie virus (RGNNV) and GGNNV, and that these viruses share the same neutralization epitope. Six predicted RNA_dependent RNA polymerase motifs are affirmed by nucleocide sequence analysis of OGNNV RNA1. According to the analysis of similarity and Phylogenelysis, OGNNV belongs to the member of RGNNV genotype.