RNA cleavage linked with ribosomal action.
Ribonuclease LS in Escherichia coli is a potential antagonist of bacteriophage T4. When T4 dmd is mutated, this RNase efficiently cleaves T4 mRNAs and leads to the silencing of late genes, thus blocking T4 growth. We previously found that, when two consecutive ochre codons were placed in the open reading frame of T4 soc, RNase LS cleaved soc mRNA at a specific site downstream of the ochre codons. Here, we demonstrate that RNase LS cleaves soc RNA at the same site even when only a single ochre codon is present or is replaced with either an amber or an opal codon. On the other hand, disruption of the Shine-Dalgarno sequence, a ribosome-binding site required for the initiation of translation, eliminates the cleavage. These results strongly suggest that RNase LS cleaves in a manner dependent on translation termination. Consistent with this suggestion, the cleavage dependency on an amber codon was considerably reduced in the presence of amber-codon-suppressing tRNA. Instead, two other cleavages that depend on translation of the region containing the target sites occurred farther downstream. Additional analysis suggests that an interaction of the ribosome with a stop codon might affect the site of cleavage by RNase LS in an mRNA molecule. This effect of the ribosome could reflect remodeling of the high-order structure of the mRNA molecule.
Yamanishi
Haruyo
H
Department of Biology, Graduate School of Science, Osaka University, Japan.
Yonesaki
Tetsuro
T
D017122:Bacteriophage T4 / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D018388:Codon, Terminator / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics; D014779:Virus Replication / Q000235:genetics*
D036022:Capsid Proteins; D018388:Codon, Terminator; D017931:DNA Primers; C453723:Dmd protein, Enterobacteria phage T4; D012333:RNA, Messenger; D014764:Viral Proteins; C103392:small outer capsid protein, bacteriophage T4; D012260:Ribonucleases