Magnesium-sensing riboswitches in bacteria

Arati Ramesh, Wade C. Winkler
2010 RNA Biology  
Metal ions play an important role in biology, acting as cofactors for enzymes, facilitating protein-protein and protein-nucleic acid interactions and stabilizing tertiary structures of proteins as well as nucleic acids. However, for most metals, an increase in their intracellular concentration beyond a certain threshold is also associated with cellular toxicity. 1 Metal concentrations within the cell are therefore subject to tight regulation, an important cellular function that is traditionally
more » ... at is traditionally attributed to metalloregulatory proteins. 2 Recent studies have also demonstrated that posttranscriptional mechanisms are often used for regulation of metal ion homeostasis. Specifically, it has become clear that different types of RNA-mediated regulatory responses may be utilized for bacterial metal ion regulation (Fig. 1) . For example, many if not most bacteria utilize small, noncoding RNAs ('ncRNAs') as trans-acting regulatory agents. 3,4 These short RNA transcripts are transcribed under specific metabolic, developmental, or stress conditions and associate to target mRNAs via Watson-Crick base pairing interactions in order to regulate translation or mRNA stability. Some of these ncR-NAs have been demonstrated to regulate metal ion homeostasis. In particular, regulatory ncRNAs have been implicated in diverse microorganisms for control of iron metabolism, including Vibrio, Escherichia, Synechocystis and Bacillus species, a subject that has been recently reviewed by others. 5,6 However, the topic of this brief review is instead on recent demonstrations that certain bacteria control metal ion homeostasis via another mode of RNA-mediated regulation, involving cis-acting RNA elements commonly referred to as riboswitches. 7
doi:10.4161/rna.7.1.10490 pmid:20023416 fatcat:k3phjeixnjgkznaopjx4b227bm