tmRNA (also known as 10Sa RNA) stands for transfer-messenger-RNA. The gene encoding the tmRNA is ssrA. It is found in all bacterial genomes that have been sequenced, and is an important part of translation regulation. To remain stable, tmRNA associates with Small Protein B (SmpB).
The purpose of tmRNA is three-fold:
1. To rescue stalled ribosomes
2. To tag the incomplete polypeptide chains
3. To promote the degradation of the aberrant mRNA
Ways to get "nonstop" mRNA are early transcriptional termination, partial degradation of the mRNA, and readthrough of inframe stop codons. Since there are no stop codons, there are no release factors. The ribosome will just sit idly on the mRNA until tmRNA or another system rescues it. It is unclear how the tmRNA-SmpB complex recognizes stalled ribosomes. To rescue the stalled ribosome, the tmRNA first behaves similarly to tRNA in that it inserts itself into the A-site of the ribosome. Then the tmRNA behaves like mRNA, and provides the ribosome with a template.
Detection of NASBA amplified bacterial tmRNA molecules on SLICSel designed microarray probes.(Nucleic Acid Sequence Based Amplification)(Methodology article)(Report)
Feb 28, 2011; Authors: Ott Scheler (corresponding author) [1,2]; Lauris Kaplinski [2,3]; Barry Glynn ; Priit Palta [2,3]; Sven Parkel [1,2];...
US Patent Issued to University of Utah Research Foundation on Sept. 14 for "Eubacterial tmRNA Sequences and Uses Thereof" (French Inventor)
Sep 15, 2010; ALEXANDRIA, Va., Sept. 16 -- United States Patent no. 7,794,944, issued on Sept. 14, was assigned to University of Utah Research...