Expression of multiple Bacillus subtilis genes is controlled by decay of slrA mRNA from Rho-dependent 3' ends.

Timely turnover of RNA is an important element in the control of bacterial gene expression, but relatively few specific targets of RNA turnover regulation are known. Deletion of theBacillus subtilis pnpAgene, encoding the major 3' exonuclease turnover enzyme, polynucleotide phosphorylase (PNPase), was shown previously to cause a motility defect correlated with a reduced level of the 32-genefla/cheflagellar biosynthesis operon transcript.fla/cheoperon transcript abundance has been shown to be inhibited by an excess of the small regulatory protein, SlrA, and here we find thatslrAmRNA accumulated in thepnpA-deletion mutant. Mutation ofslrAwas epistatic to mutation ofpnpAfor the motility-related phenotype. Further, Rho-dependent termination was required for PNPase turnover ofslrAmRNA. When theslrAgene was provided with a Rho-independent transcription terminator, gene regulation was no longer PNPase-dependent. Thus we show that theslrAtranscript is a direct target of PNPase and that regulation of RNA turnover is a major determinant of motility gene expression. The interplay of specific transcription termination and mRNA decay mechanisms suggests selection for fine-tuning of gene expression.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}