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.
Curran
J F
JF
Department of Biology, Wake Forest University, Winston-Salem, NC 27109.
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