Related Experiment Video
Updated: Jul 13, 2025

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
The ClpX protease is essential for inactivating the CI master repressor and completing prophage induction in
Mohammed A Thabet1,2, José R Penadés3, Andreas F Haag4,5
1School of Infection & Immunity, University of Glasgow, G12 8TA, Glasgow, UK.
None:
Bacteriophages (phages) are the most abundant biological entities on Earth, exerting a significant influence on the dissemination of bacterial virulence, pathogenicity, and antimicrobial resistance. Temperate phages integrate into the bacterial chromosome in a dormant state through intricate regulatory mechanisms. These mechanisms repress lytic genes while facilitating the expression of integrase and the CI master repressor. Upon bacterial SOS response activation, the CI repressor undergoes auto-cleavage, producing two fragments with the N-terminal domain (NTD) retaining significant DNA-binding ability. The process of relieving CI NTD repression, essential for prophage induction, remains unknown. Here we show a specific interaction between the ClpX protease and CI NTD repressor fragment of phages Ф11 and 80α in Staphylococcus aureus. This interaction is necessary and sufficient for prophage activation after SOS-mediated CI auto-cleavage, defining the final stage in the prophage induction cascade. Our findings unveil unexpected roles of bacterial protease ClpX in phage biology.
Related Concept Videos
Prokaryotic Transcriptional Activators and Repressors
Transcription of prokaryotic...
Anaphase Promoting Complex
CRISPR and crRNAs
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
Lysogenic Cycle of Bacteriophages
Coordination of Gene Expression Processes in Bacteria
Gene Regulation in Microbial Communities: Quorum Sensing

