title: Chromosome organization by a nucleoid-associated protein in live bacteria.
abstract: Bacterial chromosomes are confined in submicrometer-sized nucleoids. Chromosome organization is facilitated by nucleoid-associated proteins (NAPs), but the mechanisms of action remain elusive. In this work, we used super-resolution fluorescence microscopy, in combination with a chromosome-conformation capture assay, to study the distributions of major NAPs in live Escherichia coli cells. Four NAPs--HU, Fis, IHF, and StpA--were largely scattered throughout the nucleoid. In contrast, H-NS, a global transcriptional silencer, formed two compact clusters per chromosome, driven by oligomerization of DNA-bound H-NS through interactions mediated by the amino-terminal domain of the protein. H-NS sequestered the regulated operons into these clusters and juxtaposed numerous DNA segments broadly distributed throughout the chromosome. Deleting H-NS led to substantial chromosome reorganization. These observations demonstrate that H-NS plays a key role in global chromosome organization in bacteria.
authors: Department of Physics, Harvard University, Cambridge, MA 02138, USA.
authors: Wenqin
authors: W
authors: Wang
authors: Gene-Wei
authors: GW
authors: Li
authors: Chongyi
authors: C
authors: Chen
authors: X Sunney
authors: XS
authors: Xie
authors: Xiaowei
authors: X
authors: Zhuang
mesh_terms: D001665:Binding Sites; D002455:Cell Division; D002876:Chromosomes, Bacterial / Q000378:metabolism* / Q000648:ultrastructure*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D035021:Factor For Inversion Stimulation Protein / Q000378:metabolism; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D016680:Genome, Bacterial; D034982:Integration Host Factors / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D009690:Nucleic Acid Conformation; D009876:Operon; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; C529458:FimG protein, E coli; C501034:Fis protein, E coli; D034982:Integration Host Factors; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C090104:StpA protein, E coli; C116822:hns protein, E coli; C440502:integration host factor, E coli; D036781:Fimbriae Proteins