TmRNAs that encode proteolysis-inducing tags are found in all known bacterial genomes: A two-piece tmRNA functions in Caulobacter.

ABSTRACT: A general mechanism in bacteria to rescue stalled ribosomes and to clear the cell of incomplete polypeptides involves an RNA species, tmRNA (SsrA), which functions as both a tRNA and an mRNA. This RNA encodes a peptide tag that is incorporated at the end of the aberrant polypeptide and targets it for proteolysis. We have identified a circularly permuted version of the tmRNA gene in alpha-proteobacteria as well as in a lineage of cyanobacteria. The genes in these two groups seem to have arisen from two independent permutation events. As a result of the altered genetic structure, these tmRNAs are composed of two distinct RNA molecules. The mature two-piece tmRNAs are predicted to have a tRNA-like domain and an mRNA-like domain similar to those of standard one-piece tmRNAs, with a break locat

SUBMITTER: Keiler KC 

PROVIDER: S-EPMC16621 | biostudies-literature | 2000 Jul

REPOSITORIES: biostudies-literature