tRNA slippage at the tmRNA resume codon.
The bacterial ribosome does not initiate translation on the mRNA portion of tmRNA; instead translation that had begun on a separate mRNA molecule resumes at a particular triplet on tmRNA (the resume codon). For at least two tRNAs that could pair with both the resume and -2 triplets on mutant tmRNAs, UAA (stop) as the second codon induced high-frequency -2 slippage on the resume codon in the P site. The frameshift product was not detected when the -2 base was altered. Deficiency for ribosomal L9 protein, which affects other cases of frameshifting, had no significant effect. A special feature of this frameshifting is its dependence on a particular context, that of the tmRNA resume codon; it failed on the same sequence in a regular mRNA, and, more strikingly, at the second tmRNA codon. This focuses attention on the peculiar features expected of the slippage-prone state, such as unusual E-site filling, that might make the P-site resume codon:anticodon interaction especially unstable.


BACKGROUND
tmRNA; ribosome; frameshift; E site; translation
Trimble
Michael J
MJ
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Minnicus
Amy
A
Williams
Kelly P
KP
D003062:Codon; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D017930:Genes, Reporter; D014176:Protein Biosynthesis / Q000502:physiology; D012329:RNA, Bacterial / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012269:Ribosomal Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D003062:Codon; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C049650:ribosomal protein L9; C096222:tmRNA; D012343:RNA, Transfer