Regulation of sacX expression by SacY and NusG

Transcription in Bacillus subtilis is regulated at initiation, elongation, and termination. During elongation, activity of RNA polymerase is defined by pausing events stimulated by nucleic acid or protein signals. In antitermination regulatory mechanisms, pausing allows time for protein factors to bind and stabilize secondary structures in the nascent transcript, preventing termination of transcription elongation. In the sacX leader, a pause site mediated by protein factor NusG allows protein factor SacY to bind, allowing transcript readthrough.