1887

Abstract

In the two-component GacS/GacA system is required for synthesis of polyhydroxybutyrate (PHB) and of the exopolysaccharide alginate. The RsmA protein was shown to interact with the alginate biosynthetic mRNA, acting as a translational repressor, and GacA was found to activate transcription of the and genes that encode small RNAs interacting with RsmA to counteract its repressor activity. The operon encodes the enzymes of PHB synthesis and is activated by the transcriptional regulator PhbR. This study shows that GacA is required for transcription of one and seven genes present in the genome, and that inactivation of results in increased PHB production. Transcriptional and translational gene fusions were used to show that the mutation negatively affected the expression of the gene at the translational level. We also demonstrated an interaction of RsmA with RNAs corresponding to and mRNA leaders, and showed that the stability of and mRNAs is increased in the mutant. Taken together these results indicate that in , RsmA post-transcriptionally represses the expression of PhbR.

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2012-08-01
2019-08-23
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