The small RNA Sm8 modulates growth behavior at the transition into stationary phase in S. meliloti

LAGARES ANTONIO; GERMÁN CEIZEL BORELLA; BECKER, ANKE; VALVERDE, CLAUDIO

Rosario

Congreso; Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Riboregulation in bacteria stands for mechanisms of regulation of prokaryotic gene expression that are orchestrated by RNA molecules. The nitrogen-fixing legume symbiont Sinorhizobium meliloti expresses ca. 450 small trans-acting non-coding RNAs with potential regulatory functions. sRNA-mediated processes may play a distinctive role in the fine-tuning of regulation of gene expression in S. meliloti, both in free-living conditions and during the symbiotic association with the plant host Medicago sativa. The S. meliloti small non-coding RNA Sm8 has been of our particular interest because it has a remote evolutionary origin and shows a high conservation among the alpha-proteobacteria. In S. meliloti, Sm8 expression is strongly induced at the transition into the stationary phase of growth, likely as a sensor of nutrient limitation. An sm8 mutant strain shows an impaired growth behavior at the phase transition, only when growth is arrested as a consequence of an imbalance of nutrient availability. On the other hand, Sm8 overexpression promotes the opposite phenotype. Comparative transcriptomic and proteomic approaches between the wild-type and sm8 strains using cDNA microarrays and differential nitrogen-isotope proteome labeling, respectively, were performed towards to a comprehensive understanding at the molecular level of Sm8 biological role in S. meliloti.