title: Transcription termination maintains chromosome integrity.
abstract: DNA replication fork movement is impeded by collisions with transcription elongation complexes (TEC). We propose that a critical function of transcription termination factors is to prevent TEC from blocking DNA replication and inducing replication fork arrest, one consequence of which is DNA double-strand breaks. We show that inhibition of Rho-dependent transcription termination by bicyclomycin in Escherichia coli induced double-strand breaks. Cells deleted for Rho-cofactors nusA and nusG were hypersensitive to bicyclomycin, and had extensive chromosome fragmentation even in the absence of the drug. An RNA polymerase mutation that destabilizes TEC (rpoB*35) increased bicyclomycin resistance >40-fold. Double-strand break formation depended on DNA replication, and can be explained by replication fork collapse. Deleting recombination genes required for replication fork repair (recB and ruvC) increased sensitivity to bicyclomycin, as did loss of the replication fork reloading helicases rep and priA. We propose that Rho responds to a translocating replisome by releasing obstructing TEC.
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Washburn
authors.forename: Max E
authors.initials: ME
authors.lastname: Gottesman
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002875:Chromosomes / Q000187:drug effects / Q000648:ultrastructure*; D004252:DNA Mutational Analysis; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation; D010445:Peptide Elongation Factors / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D014466:Ultraviolet Rays
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D029968:Escherichia coli Proteins; C070291:NusG protein, E coli; D010445:Peptide Elongation Factors; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C068727:nusA protein, E coli; D012321:DNA-Directed RNA Polymerases; D004259:DNA-Directed DNA Polymerase; C024504:bicozamycin