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Silencing of xenogeneic DNA by H-NS—facilitation of lateral gene transfer in bacteria by a defense system that recognizes foreign DNA

Authors :
Michael McClelland
Stephen J. Libby
William Wiley Navarre
Ferric C. Fang
Source :
Genes & Development. 21:1456-1471
Publication Year :
2007
Publisher :
Cold Spring Harbor Laboratory, 2007.

Abstract

Lateral gene transfer has played a prominent role in bacterial evolution, but the mechanisms allowing bacteria to tolerate the acquisition of foreign DNA have been incompletely defined. Recent studies show that H-NS, an abundant nucleoid-associated protein in enteric bacteria and related species, can recognize and selectively silence the expression of foreign DNA with higher adenine and thymine content relative to the resident genome, a property that has made this molecule an almost universal regulator of virulence determinants in enteric bacteria. These and other recent findings challenge the ideas that curvature is the primary determinant recognized by H-NS and that activation of H-NS-silenced genes in response to environmental conditions occurs through a change in the structure of H-NS itself. Derepression of H-NS-silenced genes can occur at specific promoters by several mechanisms including competition with sequence-specific DNA-binding proteins, thereby enabling the regulated expression of foreign genes. The possibility that microorganisms maintain and exploit their characteristic genomic GC ratios for the purpose of self/non-self-discrimination is discussed.

Details

ISSN :
15495477 and 08909369
Volume :
21
Database :
OpenAIRE
Journal :
Genes & Development
Accession number :
edsair.doi.dedup.....2a7001bfbd48fe2c8d19617bc92dbfff
Full Text :
https://doi.org/10.1101/gad.1543107