title: Genome sequence of a nephritogenic and highly transformable M49 strain of Streptococcus pyogenes.
abstract: The 1,815,783-bp genome of a serotype M49 strain of Streptococcus pyogenes (group A streptococcus [GAS]), strain NZ131, has been determined. This GAS strain (FCT type 3; emm pattern E), originally isolated from a case of acute post-streptococcal glomerulonephritis, is unusually competent for electrotransformation and has been used extensively as a model organism for both basic genetic and pathogenesis investigations. As with the previously sequenced S. pyogenes genomes, three unique prophages are a major source of genetic diversity. Two clustered regularly interspaced short palindromic repeat (CRISPR) regions were present in the genome, providing genetic information on previous prophage encounters. A unique cluster of genes was found in the pathogenicity island-like emm region that included a novel Nudix hydrolase, and, further, this cluster appears to be specific for serotype M49 and M82 strains. Nudix hydrolases eliminate potentially hazardous materials or prevent the unbalanced accumulation of normal metabolites; in bacteria, these enzymes may play a role in host cell invasion. Since M49 S. pyogenes strains have been known to be associated with skin infections, the Nudix hydrolase and its associated genes may have a role in facilitating survival in an environment that is more variable and unpredictable than the uniform warmth and moisture of the throat. The genome of NZ131 continues to shed light upon the evolutionary history of this human pathogen. Apparent horizontal transfer of genetic material has led to the existence of highly variable virulence-associated regions that are marked by multiple rearrangements and genetic diversification while other regions, even those associated with virulence, vary little between genomes. The genome regions that encode surface gene products that will interact with host targets or aid in immune avoidance are the ones that display the most sequence diversity. Thus, while natural selection favors stability in much of the genome, it favors diversity in these regions.
authors.affiliation: Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, P.O. Box 26901, CPB307, Oklahoma City, OK, USA. William-McShan@ouhsc.edu
authors.forename: W Michael
authors.initials: WM
authors.lastname: McShan
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Ferretti
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Karasawa
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Suvorov
authors.forename: Shaoping
authors.initials: S
authors.lastname: Lin
authors.forename: Biafang
authors.initials: B
authors.lastname: Qin
authors.forename: Honggui
authors.initials: H
authors.lastname: Jia
authors.forename: Steve
authors.initials: S
authors.lastname: Kenton
authors.forename: Fares
authors.initials: F
authors.lastname: Najar
authors.forename: Hongmin
authors.initials: H
authors.lastname: Wu
authors.forename: Julie
authors.initials: J
authors.lastname: Scott
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Roe
authors.forename: Dragutin J
authors.initials: DJ
authors.lastname: Savic
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial; D004251:DNA Transposable Elements / Q000235:genetics; D020869:Gene Expression Profiling; D014644:Genetic Variation; D016680:Genome, Bacterial; D005810:Multigene Family; D039002:Prophages / Q000235:genetics; D011755:Pyrophosphatases / Q000235:genetics; D013297:Streptococcus pyogenes / Q000145:classification* / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence; D000096964:Nudix Hydrolases
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D011755:Pyrophosphatases; D000096964:Nudix Hydrolases