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Novel DNA binding protein SarZ contributes to virulence in Staphylococcus aureus
Author(s) -
Kaito Chikara,
Morishita Daisuke,
Matsumoto Yasuhiko,
Kurokawa Kenji,
Sekimizu Kazuhisa
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05480.x
Subject(s) - biology , mutant , virulence , hemolysin , gene , microbiology and biotechnology , dna , peptide sequence , dna binding protein , binding protein , genetics , transcription factor
Summary We previously reported that the cvfA gene is a virulence regulatory gene in Staphylococcus aureus . Here, we identified a novel gene named sarZ that acts as a multicopy suppressor of decreased haemolysin production in the cvfA deletion mutant. The amount of sarZ transcripts was decreased in the cvfA mutant. The sarZ ‐deletion mutant produced less haemolysin and attenuated virulence in a silkworm‐infection model and a mouse‐infection model. The amino acid sequence of the sarZ gene product had 19% identity with the transcription factor MarR in Escherichia coli , and the internal region contained a winged helix–turn–helix motif (wHTH), a known DNA binding domain. Purified recombinant SarZ protein had binding affinity for the promoter region of the hla gene that encodes α‐haemolysin. SarZ mutant proteins with an amino acid substitution in the N‐terminal region or in the wHTH motif had significantly decreased DNA binding. The mutated sarZ genes encoding SarZ mutant proteins with a low affinity for DNA did not complement the decreased haemolysin production or the attenuated killing ability against silkworms in the sarZ mutant. These results suggest that the DNA binding activity of the SarZ protein is required for virulence in S. aureus .