Affiliation:
1. Department of Microbiology and Immunology, New York Medical College, Valhalla, New York
Abstract
ABSTRACT
Streptococcus pyogenes
is a highly prevalent bacterial pathogen, most often giving rise to superficial infections at the throat or skin of its human host. Three genotype-defined subpopulations of strains exhibiting strong tropisms for either the throat or skin (specialists) or having no obvious tissue site preference (generalists) are recognized. Since the microenvironments at the throat and skin are distinct, the signal transduction pathways leading to the control of gene expression may also differ for throat versus skin strains of
S. pyogenes
. Two loci (
mga
and
rofA/nra
) encoding global regulators of virulence gene expression are positioned 300 kb apart on the genome; each contains alleles forming two major sequence clusters of ∼25 to 30% divergence that are under balancing selection. Strong linkage disequilibrium is observed between sequence clusters of the transcription regulatory loci and the subpopulations of throat and skin specialists, against a background of high recombination rates among housekeeping genes. A taxonomically distinct commensal species (
Streptococcus dysgalactiae
subspecies
equisimilus
) shares highly homologous
rof
alleles. The findings provide strong support for a mechanism underlying niche specialization that involves orthologous replacement of regulatory genes following interspecies horizontal transfer, although the directionality of gene exchange remains unknown.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
46 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献