SaeR binds a consensus sequence within virulence gene promoters to advance USA300 pathogenesis.
This investigation examines the role of the SaeR/S 2-component system in USA300, a prominent circulating clone of community-associated methicillin-resistant Staphylococcus aureus. Using a saeR/S isogenic deletion mutant of USA300 (USA300DeltasaeR/S) in murine models of sepsis and soft-tissue infection revealed that this sensory system is critical to pathogenesis of USA300 during both superficial and invasive infection. Oligonucleotide microarray and real-time reverse-transcriptase polymerase chain reaction identified numerous extracellular virulence genes that are down-regulated in USA300DeltasaeR/S. Unexpectedly, an up-regulation of mecA and mecR1 corresponded to increased methicillin resistance in USA300DeltasaeR/S. 5'-RACE analysis defined transcript start sites for sbi, efb, mecA, lukS-PV, hlb, SAUSA300_1975, and hla, to underscore a conserved consensus sequence within promoter regions of genes under strong SaeR/S transcriptional regulation. Electrophoretic mobility shift assay experiments illustrated direct binding of SaeR(His) to promoter regions containing the conserved consensus sequence. Collectively, the findings of this investigation demonstrate that SaeR/S directly interacts with virulence gene promoters to significantly influence USA300 pathogenesis.
Nygaard
Tyler K
TK
Department of Veterinary Molecular Biology, Montana State University-Bozeman, Bozeman, MT 59717, USA.
Pallister
Kyler B
KB
Ruzevich
Peter
P
Griffith
Shannon
S
Vuong
Cuong
C
Voyich
Jovanka M
JM
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D017714:Community-Acquired Infections / Q000382:microbiology; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000472:pathogenicity*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017384:Sequence Deletion; D018461:Soft Tissue Infections / Q000382:microbiology; D014157:Transcription Factors; D015854:Up-Regulation; D037521:Virulence Factors / Q000378:metabolism*
D001426:Bacterial Proteins; C433805:SaeR protein, Staphylococcus aureus; D014157:Transcription Factors; D037521:Virulence Factors