Analysis of effects of tRNA:message stability on frameshift frequency at the Escherichia coli RF2 programmed frameshift site.
The codon that is in-frame prior to +1 frameshifting at the E.coli prfB (RF2 gene) frameshift site is randomized to create thirty-two variants. These alleles vary 1000-fold in frameshift-dependent expression in fusions to lacZ. Frameshifting is more frequent at sites where the in-frame codon ends in uridine, as if third position wobble pairs to message uridine facilitate slippage into the +1 frame. Consistent with other studies of programmed frameshift sites, efficient frameshifting depends on stable message:tRNA base pairs after rephasing. For complexes with mispairs, frameshift frequency depends on the nature, number, and position of mispairs. Central purine:purine mispairs are especially inhibitory. Relative stabilities of +1 rephased complexes are estimated from published data on the stabilities of tRNA:tRNA complexes. Stability correlates with frameshifting over its entire range, which suggests that stability is an important determinant of the probability of translation of the rephased complex.
Department of Biology, Wake Forest University, Winston-Salem, NC 27109.
J F
JF
Curran
D000483:Alleles; D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon; D004926:Escherichia coli / Q000235:genetics*; D016368:Frameshift Mutation; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors / Q000235:genetics*; D012343:RNA, Transfer / Q000378:metabolism*; D014529:Uridine
D003062:Codon; D010454:Peptide Termination Factors; C041460:peptide chain termination release factor 2; D012343:RNA, Transfer; D014529:Uridine