SpoVG modulates cell aggregation by regulating sasC expression and eDNA release in Staphylococcus aureus.

SpoVG modulates cell aggregation by regulating sasC expression and eDNA release in Staphylococcus aureus.

Appl Environ Microbiol. 2020 May 22;:

Authors: Zhu Q, Liu B, Sun B

Abstract
Biofilm formation is involved in numerous Staphylococcus aureus infections such as endocarditis, septic arthritis, osteomyelitis, and infections on in-dwelling medical devices. In these diseases, S. aureus forms biofilms as cell aggregates interspersed in host matrix material. Here, we have observed that cell aggregation was significantly higher in the isogenic spoVG-deletion strain compared with that of the wild-type strain. Reverse transcription-quantitative PCR data indicated that SpoVG could repress the expression of sasC, which codes for S. aureus surface protein C and is involved in cell aggregation and biofilm accumulation. Electromagnetic mobility shift assay demonstrated that SpoVG could specifically bind to the promoter region of sasC, indicating that SpoVG is a negative regulator and directly represses the expression of sasC In addition, deletion of the SasC aggregation domain in the spoVG-deletion strain indicated that high level expression of sasC could be the underlying cause of significantly increased cell aggregation formation. Our previous study has shown that SpoVG is involved in oxacillin resistance of methicillin-resistant S. aureus by regulating the expression of genes involved in cell wall synthesis and degradation. In this study, we also have found that SpoVG can negatively modulate the S. aureus drug tolerance under high concentration of oxacillin treatment. These findings can broaden our understanding of the regulation of biofilm formation and drug tolerance in S. aureus IMPORTANCE This study has revealed that SpoVG can modulate cell aggregation by repressing sasC expression and eDNA release. Furthermore, we have demonstrated the potential linkage between cell aggregation and antibiotic resistance. Our findings provide novel insights into the regulatory mechanisms of SpoVG involved in cell aggregation, biofilm development and formation in Staphylococcus aureus.

PMID: 32444467 [PubMed - as supplied by publisher]