Transfer RNA-mediated antitermination in vitro.

Abstract

The threonyl-tRNA synthetase gene (thrS) is a member of the T-box family of approximately 250 genes, found essentially in Gram-positive bacteria, regulated by a tRNA-dependent antitermination mechanism in response to starvation for the cognate amino acid. While interaction between uncharged tRNA and the untranslated leader region of these genes has been firmly established by genetic means, attempts to show this interaction or to reconstitute the antitermination mechanism in vitro using purified tRNAs have so far failed. In addition, a number of conserved sequences have been identified in the T-box leaders, for which no function has yet been assigned. This suggests that factors other than the tRNA are important for this type of control. Here we demonstrate tRNA-mediated antitermination for the first time in vitro, using the regulatory tRNA(Thr) isoacceptor isolated from Bacillus subtilis and a partially purified protein fraction. As predicted by the model, aminoacylation of tRNA(Thr(GGU)) with threonine completely abolishes its ability to act as an effector. The role of the partially purified protein fraction can be functionally substituted by high concentrations of spermidine. However, this polyamine does not play a significant role in the induction of thrS expression in vivo, suggesting that it is specific protein co-factors that promote T-box gene regulation in conjunction with uncharged tRNA.

• Authors: Harald Putzer, Ciarán Condon, Dominique Brechemier-Baey, Renata Brito, Marianne Grunberg-Manago
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 30 Issue 14 Pg. 3026-33 (Jul 15 2002) ISSN: 1362-4962 [Electronic] England
• PMID: 12136084 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anticodon
• Bacterial Proteins
• Exotoxins
• Membrane Proteins
• RNA, Bacterial
• RNA, Transfer, Thr
• SpeA protein, Streptococcus pyogenes
• RNA, Transfer
• Threonine-tRNA Ligase

Topics

• Anticodon (genetics)
• Bacillus subtilis (genetics, metabolism)
• Bacterial Proteins (genetics)
• Exotoxins
• Membrane Proteins (genetics)
• Mutation
• RNA, Bacterial (genetics, metabolism)
• RNA, Transfer (genetics, metabolism)
• RNA, Transfer, Thr (genetics, metabolism)
• Terminator Regions, Genetic (genetics)
• Threonine-tRNA Ligase (genetics, metabolism)
• Transcription, Genetic (genetics)