Near-cognate peptidyl-tRNAs promote +1 programmed translational frameshifting in yeast.
Translational frameshifting is a ubiquitous, if rare, form of alternative decoding in which ribosomes spontaneously shift reading frames during translation elongation. In studying +1 frameshifting in Ty retrotransposons of the yeast S. cerevisiae, we previously showed that unusual P site tRNAs induce frameshifting. The frameshift-inducing tRNAs we show here are near-cognates for the P site codon. Their abnormal decoding induces frameshifting in either of two ways: weak codon-anticodon pairing allows the tRNA to disengage from the mRNA and slip +1, or an unusual codon-anticodon structure interferes with cognate in-frame decoding allowing out-of-frame decoding in the A site. We draw parallels between this mechanism and a proposed mechanism of frameshift suppression by mutant tRNAs.
Sundararajan
A
A
Department of Biological Sciences, University of Maryland, Baltimore County 21250, USA.
Michaud
W A
WA
Qian
Q
Q
Stahl
G
G
Farabaugh
P J
PJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D018965:Frameshifting, Ribosomal; D008969:Molecular Sequence Data; D009154:Mutation; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D018626:Retroelements / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D012346:RNA, Transfer, Amino Acyl; D018626:Retroelements; C019037:tRNA, peptidyl-