Transcription termination controls prophage maintenance in Escherichia coli genomes.
Prophages represent a large fraction of prokaryotic genomes and often provide new functions to their hosts, in particular virulence and fitness. How prokaryotic cells maintain such gene providers is central for understanding bacterial genome evolution by horizontal transfer. Prophage excision occurs through site-specific recombination mediated by a prophage-encoded integrase. In addition, a recombination directionality factor (or excisionase) directs the reaction toward excision and prevents the phage genome from being reintegrated. In this work, we describe the role of the transcription termination factor Rho in prophage maintenance through control of the synthesis of transcripts that mediate recombination directionality factor expression and, thus, excisive recombination. We show that Rho inhibition by bicyclomycin allows for the expression of prophage genes that lead to excisive recombination. Thus, besides its role in the silencing of horizontally acquired genes, Rho also maintains lysogeny of defective and functional prophages.
Laboratoire de Chimie Bactérienne, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7283, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, 13402 Marseille Cedex 20, France.
Rachid
R
Menouni
Stéphanie
S
Champ
Leon
L
Espinosa
Marc
M
Boudvillain
Mireille
M
Ansaldi
D003090:Coliphages / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics / Q000821:virology*; D029968:Escherichia coli Proteins / Q000235:genetics; D020868:Gene Silencing; D016680:Genome, Bacterial; D008242:Lysogeny; D039002:Prophages / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D011995:Recombination, Genetic; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; C488589:TorI protein, E coli
bacteriophage; transcriptional regulation; transduction