Inhibition of factor-dependent transcription termination in Escherichia coli might relieve xenogene silencing by abrogating H-NS-DNA interactions in vivo.
Many horizontally acquired genes (xenogenes) in the bacterium Escherichia coli are maintained in a silent transcriptional state by the nucleoid-associated transcription regulatory protein H-NS. Recent evidence has shown that antibiotic-mediated inhibition of the transcription terminator protein Rho leads to de-repression of horizontally acquired genes, akin to a deletion of hns. The mechanism behind this similarity in outcomes between the perturbations of two distinct processes remains unclear. Using ChIP-seq of H-NS in wild-type cells, in addition to that in cells treated with bicyclomycin--a specific inhibitor of Rho, we show that bicyclomycin treatment leads to a decrease in binding signal for H-NS to the E. coli chromosome. Rho inhibition leads to RNA polymerase readthrough, which in principle could displace H-NS from the DNA, thus leading to transcriptional derepression of H-NS-silenced genes. Other possible mediators of the effect of Rho on H-NS are discussed. A possible positive feedback between Rho and H-NS might help reinforce xenogene silencing.
National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560 065, India.
Deepti
D
Chandraprakash
Aswin Sai Narain
AS
Seshasayee
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D047369:Chromatin Immunoprecipitation; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology; D036781:Fimbriae Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology*; D022761:Gene Transfer, Horizontal / Q000502:physiology*; D059014:High-Throughput Nucleotide Sequencing; D061806:Transcription Termination, Genetic / Q000502:physiology*
D019086:Bridged Bicyclo Compounds, Heterocyclic; D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; C534627:Rho protein, E coli; D036781:Fimbriae Proteins; C024504:bicozamycin