Identification of a major, CsrRS-regulated secreted protein of Group A streptococcus.

CsrR/CsrS (CovR/CovS) is a two-component regulator of extracellular virulence factors in Group A streptococcus, but the full range of regulated exoproteins is unknown. Since CsrR represses expression of regulated factors, culture supernates of wild-type and CsrR(-)mutant strains were compared by two-dimensional gel electrophoresis (2DGE) to identify regulated exoproteins. Supernates of DeltacsrRS(-)mutant, but not wild-type, bacteria contained an abundant 23 kDa protein. The N-terminal sequence of this spot corresponded to a putative open reading frame (ORF) in the streptococcal genome. In a mobility shift assay, phosphorylated CsrR bound to a PCR amplicon that included sequences upstream of this ORF. By primer extension analysis, the ORF (designated mspA, for Mucoidy-associated Secreted Protein) was expressed in mid- and late-exponential phase in a DeltacsrRS(-)mutant. The presence of an in-frame deletion in mspA did not affect colony appearance, mucoidy or in vitro growth, and there was no difference between DeltamspA and wild-type strains in a mouse model of skin infection. MspA is co-regulated with other factors required for dermonecrosis (e.g. capsule, streptolysin S and purogenic exotoxin B); however, deletion of this gene does not affect expression of hyaluronic acid capsule or severity of skin infection in mice.

Heath A ，Miller A ，DiRita VJ ，Engleberg CN ... -  《MICROBIAL PATHOGENESIS》

Use of DNA arrays to identify a mutation in the negative regulator, csrR, responsible for the high virulence of a naturally occurring type M3 group A streptococcus clinical isolate.

Miyoshi-Akiyama T ，Ikebe T ，Watanabe H ，Uchiyama T ，Kirikae T ，Kawamura Y ... -  《-》

Spontaneous mutations in the CsrRS two-component regulatory system of Streptococcus pyogenes result in enhanced virulence in a murine model of skin and soft tissue infection.

Engleberg NC ，Heath A ，Miller A ，Rivera C ，DiRita VJ ... -  《-》

Analysis of the role of CovR and CovS in the dissemination of Streptococcus pyogenes in invasive skin disease.

Dalton TL ，Hobb RI ，Scott JR 《MICROBIAL PATHOGENESIS》

A two-component regulatory system, CsrR-CsrS, represses expression of three Streptococcus pyogenes virulence factors, hyaluronic acid capsule, streptolysin S, and pyrogenic exotoxin B.

Heath A ，DiRita VJ ，Barg NL ，Engleberg NC ... -  《-》