Open AccessDifferential Target Gene Activation by the Staphylococcus aureus Two-Component System saeRS
Author(s) -
Markus Mainiero,
Christiane Goerke,
Tobias Geiger,
Christoph Gonser,
Silvia Herbert,
Christiane Wolz
Publication year - 2010
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.01242-09
Subject(s) - biology , staphylococcus aureus , component (thermodynamics) , microbiology and biotechnology , differential (mechanical device) , bacterial protein , gene , bacteria , genetics , physics , engineering , aerospace engineering , thermodynamics
ThesaePQRS system ofStaphylococcus aureus controls the expression of major virulence factors and encodes a histidine kinase (SaeS), a response regulator (SaeR), a membrane protein (SaeQ), and a lipoprotein (SaeP). The widely used strain Newman is characterized by a single amino acid change in the sensory domain of SaeS (Pro18 in strain Newman [SaeSP ], compared with Leu18 in other strains [SaeSL ]). SaeSP determines activation of the class Isae target genes (coa ,fnbA ,eap ,sib ,efb ,fib ,sae ), which are highly expressed in strain Newman. In contrast, class II target genes (hla ,hlb ,cap ) are not sensitive to the SaeS polymorphism. The SaeSL allele (saeSL ) is dominant over the SaeSP allele, as shown by single-copy integration ofsaePQRSL in strain Newman, which results in severe repression of class I target genes. The differential effect on target gene expression is explained by different requirements for SaeR phosphorylation. From an analysis ofsaeS deletion strains and strains with mutated SaeR phosphorylation sites, we concluded that a high level of SaeR phosphorylation is required for activation of class I target genes. However, a low level of SaeR phosphorylation, which can occur independent of SaeS, is sufficient to activate class II target genes. Using induciblesaeRS constructs, we showed that the expression of both types of target genes is independent of thesaeRS dosage and that the typical growth phase-dependent gene expression pattern is not driven by SaeRS.