Competition between trans-translation and termination or elongation of translation.
The effects of tRNA, RF1 and RRF on trans-translation by tmRNA were examined using a stalled complex of ribosome prepared using a synthetic mRNA and pure Escherichia coli translation factors. No endoribonucleolytic cleavage of mRNA around the A site was found in the stalled ribosome and was required for the tmRNA action. When the A site was occupied by a stop codon, alanyl-tmRNA competed with RF1 with the efficiency of peptidyl-transfer to alanyl-tmRNA for trans-translation inversely correlated to the efficiency of translation termination. The competition was not affected by RF3. A sense codon also serves as a target for alanyl-tmRNA with competition of aminoacyl-tRNA. The extent of inhibition was decreased with the length of the 3'-extension of mRNA. RRF, only at a high concentration, slightly affected peptidyl-transfer for trans-translation, although it did not affect the canonical elongation. These results indicate that alanyl-tmRNA does not absolutely require the truncation of mRNA around the A site but prefers an mRNA of a short 3'-extension from the A site and that it can operate on either a sense or termination codon at the A site, at which alanyl-tmRNA competes with aminoacyl-tRNA, RF and RRF.
Asano
Krisana
K
Department of Biochemistry and Biotechnology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan.
Kurita
Daisuke
D
Takada
Kazuma
K
Konno
Takayuki
T
Muto
Akira
A
Himeno
Hyouta
H
D000409:Alanine / Q000378:metabolism; D018388:Codon, Terminator; D010441:Peptide Chain Elongation, Translational; D010443:Peptide Chain Termination, Translational; D010454:Peptide Termination Factors / Q000378:metabolism; D012329:RNA, Bacterial / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D014633:Valine / Q000378:metabolism
D018388:Codon, Terminator; D010454:Peptide Termination Factors; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C087971:peptide-chain-release factor 3; C087267:ribosome releasing factor; C096222:tmRNA; D014633:Valine; D000409:Alanine