Inter- and intraserotypic variation in the Streptococcus pyogenes Rgg regulon

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Streptococcus pyogenes exhibits considerable genetic and phenotypic diversity.
• The rgg locus (ropB) acts as a global transcriptional regulator in S. pyogenes strain NZ131, influencing metabolism, stress, and virulence.
• Understanding the Rgg regulon's scope is crucial for comprehending S. pyogenes variation.

Purpose of the Study:

• To determine the breadth of the Rgg regulon across different S. pyogenes strains and serotypes.
• To identify the core and strain-specific components of the Rgg regulon.
• To investigate interserotypic and intraserotypic variation in Rgg regulation.

Main Methods:

• Inactivation of the rgg gene in three distinct S. pyogenes strains (SF370, MGAS5005, CS101) representing serotypes M1 and M49.
• Analysis of gene expression changes in the postexponential growth phase using Affymetrix NimbleExpress Arrays.
• Comparative analysis of Rgg regulon components across different strains.

Main Results:

• Identification of a conserved Rgg core-regulon comprising speB and spy2040.
• Discovery of a variable, strain-specific subregulon, with sizes ranging from one gene (spy1793 in MGAS5005) to 43 genes (in SF370).
• Demonstration of significant interserotypic and intraserotypic variation in the Rgg regulon.

Conclusions:

• The Rgg regulon in S. pyogenes is characterized by both core and highly variable, strain-specific components.
• Genetic variation within the Rgg regulon contributes to the diversity observed in S. pyogenes.
• These findings highlight the complex regulatory landscape influencing S. pyogenes virulence and adaptation.