Coupling of open reading frames by translational bypassing.
Translational bypassing joins the information found within two disparate open reading frames into a single polypeptide chain. The underlying mechanism centers on the decoding properties of peptidyl-transfer RNA (tRNA) and involves three stages: take-off, scanning, and landing. In take-off, the peptidyl-tRNA/messenger RNA (mRNA) complex in the P site of the ribosome dissociates, and the mRNA begins to move through the ribosome. In scanning, the peptidyl-tRNA probes the mRNA sliding through the decoding center. In landing, the peptidyl-tRNA re-pairs with a codon with which it can form a stable interaction. Although few examples of genes are known that rely on translational bypassing to couple open reading frames, ribosomes appear to have an innate capacity for bypassing. This suggests that the strategy of translational bypassing may be more common than presently appreciated. The best characterized example of this phenomenon is T4 gene 60, in which a complex set of signals stimulates bypassing of 50 nucleotides between the two open reading frames. In this review, we focus on the bypassing mechanism of gene 60 in terms of take-off, scanning, and landing.
Herr
A J
AJ
Department of Human Genetics, The University of Utah, Salt Lake City, Utah 84112-5330, USA. aherr@genetics.utah.edu
Atkins
J F
JF
Gesteland
R F
RF
D000595:Amino Acid Sequence; D001483:Base Sequence; D005798:Genes, Bacterial; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010443:Peptide Chain Termination, Translational; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000235:genetics / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism
D021382:Protein Sorting Signals; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C049650:ribosomal protein L9; C019037:tRNA, peptidyl-