Affiliation:
1. Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536
2. Microbial Sciences Institute, Yale University, West Haven, CT 06516
Abstract
Horizontal gene transfer drives bacterial evolution. To confer new properties, horizontally acquired genes must overcome gene silencing by nucleoid-associated proteins, such as the heat-stable nucleoid structuring (H-NS) protein. Enteric bacteria possess proteins that displace H-NS from foreign genes, form nonfunctional oligomers with H-NS, and degrade H-NS, raising the question of whether any of these mechanisms play a role in overcoming foreign gene silencing in vivo. To answer this question, we mutagenized the
hns
gene and identified a variant specifying an H-NS protein that binds foreign DNA and silences expression of the corresponding genes, like wild-type H-NS, but resists degradation by the Lon protease. Critically,
Escherichia coli
expressing this variant alone fails to produce curli, which are encoded by foreign genes and required for biofilm formation, and fails to colonize the murine gut. Our findings establish that H-NS proteolysis is a general mechanism of derepressing foreign genes and essential for colonization of mammalian hosts.
Funder
HHS | NIH | National Institute of Allergy and Infectious Diseases
Publisher
Proceedings of the National Academy of Sciences
Cited by
4 articles.
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