Regulation of acetate metabolism and coordination with the TCA cycle via a processed small RNA

Significance In bacteria, small RNAs pair with target mRNAs to rapidly adjust gene expression in response to environmental and physiological changes. In this study, we identified a small RNA, SdhX, inEscherichia coli , whose expression is dependent on expression of tricarboxylic acid cycle genes. SdhX adjusts carbon flux by negatively regulating acetate kinase levels, improving growth on acetate. SdhX also leads to increased resistance to hydroxyurea, as do deletions of acetate kinase. Balancing metabolic flux is important for all bacterial cells, and SdhX plays a major role in this process by linking expression of tricarboxylic acid cycle genes to regulation of acetate metabolism, thus playing a role in gating overflow metabolism.