摘要
以λ-ZAPⅡ噬菌体为载体,构建了番木瓜环斑病毒华南强株系(PRV-SM)基因组cDNA文库。以PCR扩增的外壳蛋白(CP)基因为探针筛选出阳性克隆。酶谱和序列分析确定,其中两个阳性克隆除重叠部分外为长达2676个核苷酸的基因组3′端区域。其中包括棱内含体蛋白b(NIb)基因的1607个棱苷酸,CP基因的858个核苷酸和基因组3′端非编码区的211个核苷酸(不包括polyA尾巴)。PRV-SM的NIb含有依赖于RNA的RNA聚合酶的8个特征性保守序列,可能是参与基因组RNA复制的核心亚基。与其他株系比较,NIb的氨基酸变化主要集中在其C端和N端。PRV-SM 3′端非编码区有一段28个核苷酸的正向重复序列,能在其内形成茎环二级结构,并且在各株系间具有高度保守性。NIb,CP和3′端非编码区的总的序列比较表明,SM株系与国外报道的其他株系亲缘关系相对较远。
A cDNA library of a Chinese severe strain of papaya ringspot virus ( PRV-SM)was constructed in the lambda ZAPⅡ vector. When selected with PCR amplified virai coat protein ( CP ) gene as probe, two posit-ive clones were obtained. Restriction enzyme mapping and sequence an alysis showed that the 3'-terminal 2676 nucleotides of PRV- SM genome was cloned, which include 1607 nucleotides of nuclear inclusion protein b ( NIb ) gene, 858 nucleotides of CP gene and 211 nucleotides of 3' untranslated region ( 3-UTR) . NIb which shares eight characteristic conserved motifs of RNA- dependent RNA polymerases, might be the core subunit of the RNA replicase ccmplex. The N- and C-terminal regions of NIb shcw much diversity between SM and other strains of PRV. There is a direct repeat of 23 nucleotides in 3'-UTR that is ca pable of forming a stem-loop structure and is highly conserved in PRV strains. Se quence comparisons of NIb, CP and 3'- UTR indicated that SM is less homologous with the strains of PRV reporled in the literature.
出处
《病毒学报》
CAS
CSCD
北大核心
1993年第3期246-254,共9页
Chinese Journal of Virology
基金
国家"八.五"攻关项目
关键词
番木瓜
环斑病毒
CDNA文库
Papaya ringspot virus, cDNA library, Nuclear inclusion protein b gene, Coat protein gene, 3'- untranslated region.
