Affiliation:
1. Graduate Institute of Agricultural Biotechnology,1
2. Graduate Institute of Biochemistry,2 and
3. Agricultural Biotechnology Laboratories,3 National Chung Hsing University, Taichung, Taiwan 40227, Republic of China
Abstract
ABSTRACT
Bamboo mosaic virus (BaMV), a member of the potexvirus group, infects primarily members of the
Bambusoideae
. The open reading frame 1 (ORF1) of BaMV encodes a 155-kDa polypeptide that was postulated to be involved in the replication and the formation of cap structure at the 5′ end of the viral genome. To characterize the activities associated with the 155-kDa viral protein, it was expressed in
Escherichia coli
BL21(DE3) cells with thioredoxin, hexahistidine, and S · Tag fused consecutively at its amino terminus, and the fusion protein was purified by metal affinity chromatography. Several RNA fragments, prepared by in vitro transcription, were tested as substrates for the RNA-dependent RNA polymerase (RdRp) activity. Among them, the expressed fusion enzyme was able to generate a
32
P-labeled RNA product when 3′-end RNA fragments of the positive strand or negative strand of BaMV were included in the assay mixture. Dot hybridization assay revealed that the reaction products are complementary to their RNA substrates. Taken together, the evidence suggests that the 155-kDa protein encoded by ORF1 of BaMV has an RdRp activity and should be involved in the replication of BaMV. Mutational analyses demonstrate the importance of the GDD motif in the polymerase activity, and deletion studies suggest that the polymerase activity resides in the carboxyl terminus of the 155-kDa viral protein.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Cited by
73 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献