title: Xenogeneic Silencing and Its Impact on Bacterial Genomes.
abstract: The H-NS (heat-stable nucleoid structuring) protein affects both nucleoid compaction and global gene regulation. H-NS appears to act primarily as a silencer of AT-rich genetic material acquired by horizontal gene transfer. As such, it is key in the regulation of most genes involved in virulence and in adaptation to new environmental niches. Here we review recent progress in understanding the biochemistry of H-NS and how xenogeneic silencing affects bacterial evolution. We highlight the strengths and weaknesses of some of the models proposed in H-NS-mediated nucleoprotein complex formation. Based on recent single-molecule studies, we also propose a novel mode of DNA compaction by H-NS termed intrabridging to explain over two decades of observations of the H-NS molecule.
authors.affiliation: Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada; email: william.navarre@utoronto.ca.
authors.forename: Kamna
authors.initials: K
authors.lastname: Singh
authors.affiliation: Department of Chemical and Physical Sciences, University of Toronto Mississauga, Ontario L5L 1C6, Canada.|Department of Physics, University of Toronto, Ontario M5S 1A7, Canada.
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Milstein
authors.affiliation: Department of Molecular Genetics, University of Toronto, Ontario M5S 1A8, Canada; email: william.navarre@utoronto.ca.
authors.forename: William Wiley
authors.initials: WW
authors.lastname: Navarre
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D020868:Gene Silencing; D016680:Genome, Bacterial
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria
keywords: H-NS; genome evolution; horizontal gene transfer; nucleoid-associated proteins; xenogeneic silencing