Transcriptional silencing in bacteria.

Transcriptional silencing and repression are modes of negative control of gene expression that differ in specificity. Repressors, when present at promoter-specific binding sites, interfere locally with RNA polymerase function. Silencing proteins act by covering a continuous region of DNA, compete with a broader spectrum of proteins and are non-specific with respect to the promoters affected. Studies of transcriptional silencing promise an entrée to relatively unexplored areas of prokaryotic biology.