Portal de Periódicos da CAPES

Chromosome Organization by a Nucleoid-Associated Protein in Live Bacteria

2011; American Association for the Advancement of Science; Volume: 333; Issue: 6048 Linguagem: Inglês

10.1126/science.1204697

1095-9203

Wenqin Wang, Gene‐Wei Li, Chongyi Chen, X. Sunney Xie, Xiaowei Zhuang,

Bacteriophages and microbial interactions

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.