Mutational analysis of the tRNA mimicry of brome mosaic virus RNA. Sequence and structural requirements for aminoacylation and 3'-adenylation.
The genomic RNAs of brome mosaic virus (BMV) exhibit various tRNA-like properties, including specific tyrosylation by tyrosyl-tRNA synthetases and adenylation of the 3'-CCOH derivative by tRNA nucleotidyl transferases. We have studied the effect of numerous mutations in all domains of the tRNA-like structure of BMV RNA on tyrosylation and adenylation in vitro. Surprisingly few mutations resulted in more than 50% decrease in tyrosylation rates with either wheat germ or yeast synthetases; those mutations were at the 3' terminus, the pseudoknot, and the bases of arms B and E. The results suggest an interaction of synthetase with arm A as the analog of the aminoacyl acceptor stem of tRNAs, and arm B as the analog of the anticodon arm of tRNAs, although there is no apparent interaction with the terminal loop of arm B analogous to the interaction with the anticodon in tRNAs. Mutations at several loci resulted in large losses of adenylation activity catalyzed by wheat germ and Escherichia coli nucleotidyl transferases; those loci were the pseudoknot, the bases of arms B, C and D, and at the junctions of these arms with arm A. These studies have identified mutants specifically defective in one of the tRNA-like activities, which are appropriate for investigating the role of these activities during infection in vivo.
Department of Biology, Texas A & M University, College Station 77843-3258.
T W
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Dreher
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Hall
D001345:Autoradiography; D001483:Base Sequence; D004252:DNA Mutational Analysis; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics*; D009154:Mutation; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D012343:RNA, Transfer / Q000235:genetics* / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014443:Tyrosine / Q000378:metabolism
D012367:RNA, Viral; D014443:Tyrosine; D012343:RNA, Transfer; D012316:RNA Nucleotidyltransferases; C023198:tRNA nucleotidyltransferase