3′ Untranslated Region-Dependent Degradation of theaceAmRNA, Encoding the Glyoxylate Cycle Enzyme Isocitrate Lyase, by RNase E/G in Corynebacterium glutamicum
ABSTRACTWe previously reported that theCorynebacterium glutamicumRNase E/G encoded by therneGgene (NCgl2281) is required for the 5′ maturation of 5S rRNA. In the search for the intracellular target RNAs of RNase E/G other than the 5S rRNA precursor, we detected that the amount of isocitrate lyase, an enzyme of the glyoxylate cycle, increased inrneGknockout mutant cells grown on sodium acetate as the sole carbon source. Rifampin chase experiments showed that the half-life of theaceAmRNA was about 4 times longer in therneGknockout mutant than in the wild type. Quantitative real-time PCR analysis also confirmed that the level ofaceAmRNA was approximately 3-fold higher in therneGknockout mutant strain than in the wild type. Such differences were not observed in other mRNAs encoding enzymes involved in acetate metabolism. Analysis by 3′ rapid amplification of cDNA ends suggested that RNase E/G cleaves theaceAmRNA at a single-stranded AU-rich region in the 3′ untranslated region (3′-UTR). ThelacZfusion assay showed that the 3′-UTR renderedlacZmRNA RNase E/G dependent. These findings indicate that RNase E/G is a novel regulator of the glyoxylate cycle inC. glutamicum.