Serum opacity factor promotes group A streptococcal epithelial cell invasion and virulence

Timmer, Anjuli M., Kristian, Sascha A., Datta, Vivekanand, Jeng, Arthur, Gillen, Christine M., Walker, Mark J., Beall, Bernard and Nizet, Victor (2006) Serum opacity factor promotes group A streptococcal epithelial cell invasion and virulence. Molecular Microbiology, 62 1: 15-25. doi:10.1111/j.1365-2958.2006.05337.x

Author Timmer, Anjuli M.
Kristian, Sascha A.
Datta, Vivekanand
Jeng, Arthur
Gillen, Christine M.
Walker, Mark J.
Beall, Bernard
Nizet, Victor
Title Serum opacity factor promotes group A streptococcal epithelial cell invasion and virulence
Journal name Molecular Microbiology   Check publisher's open access policy
ISSN 0950-382X
Publication date 2006-10
Sub-type Article (original research)
DOI 10.1111/j.1365-2958.2006.05337.x
Volume 62
Issue 1
Start page 15
End page 25
Total pages 11
Place of publication Oxford, England, U.K.
Publisher Wiley-Blackwell Publishing
Language eng
Formatted abstract
Serum opacity factor (SOF) is a bifunctional cell surface protein expressed by 40-50% of group A streptococcal (GAS) strains comprised of a C-terminal domain that binds fibronectin and an N-terminal domain that mediates opacification of mammalian sera. The sof gene was recently discovered to be cotranscribed in a two-gene operon with a gene encoding another fibronectin-binding protein, sfbX. We compared the ability of a SOF(+) wild-type serotype M49 GAS strain and isogenic mutants lacking SOF or SfbX to invade cultured HEp-2 human pharyngeal epithelial cells. Elimination of SOF led to a significant decrease in HEp-2 intracellular invasion while loss of SfbX had minimal effect. The hypoinvasive phenotype of the SOF(-) mutant could be restored upon complementation with the sof gene on a plasmid vector, and heterologous expression of sof49 in M1 GAS or Lactococcus lactis conferred marked increases in HEp-2 cell invasion. Studies using a mutant sof49 gene lacking the fibronectin-binding domain indicated that the N-terminal opacification domain of SOF contributes to HEp-2 invasion independent of the C-terminal fibronectin binding domain, findings corroborated by observations that a purified SOF N-terminal peptide could promote latex bead adherence to HEp-2 cells and inhibit GAS invasion of HEp-2 cells in a dose-dependent manner. Finally, the first in vivo studies to employ a single gene allelic replacement mutant of SOF demonstrate that this protein contributes to GAS virulence in a murine model of necrotizing skin infection. © 2006 The Authors.
Keyword Fibronectin-Binding Protein
Distinct Classes
Surface Protein
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: ERA 2012 Admin Only
School of Chemistry and Molecular Biosciences
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