Abstract
RNA molecules play critical roles in cell biology, and novel findings continuously broaden their functional repertoires. Apart from their wellโdocumented participation in protein synthesis, it is now apparent that several noncoding RNAs (i.e., microโRNAs and riboswitches) also participate in the regulation of gene expression. The discovery of catalytic RNAs had profound implications on our views concerning the evolution of life on our planet at a molecular level. A characteristic attribute of RNA, probably traced back to its ancestral origin, is the ability to interact with and be modulated by several ions and molecules of different sizes. The inhibition of ribosome activity by antibiotics has been extensively used as a therapeutical approach, while activation and substrateโspecificity alteration have the potential to enhance the versatility of ribozymeโbased tools in translational research. In this review, we will describe some representative examples of such modulators to illustrate the potential of catalytic RNAs as tools and targets in research and clinical approaches. ยฉ 2008 IUBMB IUBMB Life, 60(10): 669โ683, 2008.