新城疫分离毒HN基因的分子特性和片段同源相关性

选取国内1997-2005年分离的新城疫病毒(Newcastle disease virus,NDV)24株,经蚀斑纯化克隆其血凝素-神经氨酸酶(HN)基因,与在GenBank发表的36株国内外不同时期的NDV毒株,进行氨基酸遗传变异分析,并利用SPSS8.0软件对其不同片段的氨基酸进行同源相关比较。结果显示:国内所有NDV分离毒株氨基酸高度同源,同源性为94.4%-99.4%;与LaSota、Clone30疫苗株等的氨基酸同源性为86.9%-89%;与强毒株F48E9的氨基酸同源性为87.9%-89.9%;与国外NDV的氨基酸同源性为87.2%-96.2%。系统发育分析表明:国内NDV分离毒HN遗传距离较近,而与LaSota、Clone30和F48E9遗传距离较远。国内NDV分离毒均缺乏538-540位糖基化位点。不同片段与全长的氨基酸同源性高度相关,且与前80个氨基酸相关最密切。

Genetic Characterization and Correlation among Fragments of HN Gene of the Field Newcastle Disease Viruses

Twenty-four isolates of Newcastle disease virus (NDV) prevailing during 1997 -- 2005 in China were collected. These isolates were purified by CEF plaque assay and replicated in SPF chicken embryos. The hemagglutinin-neuraminidase (HN) genes of these viruses were cloned and sequenced. The HN gene sequences of thirty-six NDV reference strains in GenBank were also used in this study. The amino acid homologing of these viruses were compared and analyzed. The correlations among different fragments of HN gene were also analyzed. The results indicated that the homology of Chinese field NDV strains was 94.4%-99.4%, but 86.9%-89% compared with LaSota and Clone30, 87.9%-89.9% to F48E9, and 87.2%-96.2% to foreign NDV strains. There had the nearest distances among Chinese NDV isolates as compared with that of the LaSota, Clone30 and F48E9 by the phylogenetic tree. However, the distances of seven foreign NDV isolates were very close to Chinese NDV isolates as compared with these of the other foreign NDV isolates. We also found that all the Chinese field isolates were devoid of glycosylation site in position 538 -- 540. There were good correlations between different length amino acid fragments and the genomes of HN, especially the 5'-terminus first 80aa.