Release factor 2 frameshifting sites in different bacteria.
The mRNA encoding Escherichia coli polypeptide chain release factor 2 (RF2) has two partially overlapping reading frames. Synthesis of RF2 involves ribosomes shifting to the +1 reading frame at the end of the first open reading frame (ORF). Frameshifting serves an autoregulatory function. The RF2 gene sequences from the 86 additional bacterial species now available have been analyzed. Thirty percent of them have a single ORF and their expression does not require frameshifting. In the approximately 70% that utilize frameshifting, the sequence cassette responsible for frameshifting is highly conserved. In the E. coli RF2 gene, an internal Shine-Dalgarno (SD) sequence just before the shift site was shown earlier to be important for frameshifting. Mutagenic data presented here show that the spacer region between the SD sequence and the shift site influences frameshifting, and possible mechanisms are discussed. Internal translation initiation occurs at the shift site, but any functional role is obscure.
Baranov
Pavel V
PV
Department of Human Genetics, University of Utah, 15N 2030E Room 7410, Salt Lake City, UT 84112-5330, USA.
Gesteland
Raymond F
RF
Atkins
John F
JF
D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics*; D018965:Frameshifting, Ribosomal; D010454:Peptide Termination Factors / Q000235:genetics*; D014176:Protein Biosynthesis / Q000502:physiology
D010454:Peptide Termination Factors; C041460:peptide chain termination release factor 2