Exploration of Modulated Genetic Circuits Governing Virulence Determinants in Staphylococcus aureus

Abstract

The expression of virulence genes in the human pathogen Staphylococcus aureus is strongly influenced by the multiple global regulators. The signal transduction cascade of these global regulators is accountable for recognizing and integrating the environmental cues to regulate the virulence regulon. While the production of virulent factors by individual global regulators are comparatively straightforward to define, auto-regulation of these global regulators and their impact on other regulators is more complex process. There are several reports on the production of virulent factors that are precisely regulated by switching processes of multiple global regulators including some prominent accessory regulators such as agr, sae and sar which allows S. aureus to coordinate the gene expression, and thus, provide organism an ability to act collectively. This review implicates the mechanisms involved in the global regulation of various virulence factors along with a comprehensive discussion on the differences between these signal transduction systems, their auto-induction and, coordination of classical and some comparatively new bacterial signal transduction systems.

Keywords: Global regulators; Signal transduction system; Staphylococcus aureus; Virulence determinants.

Fig. 1

The intricate molecular mechanism for the virulence gene expressions in Staphylococcus aureus. Positive and negative symbols depict the up-regulation and down-regulation of virulence determinants

Fig. 2

The Agr quorum sensing circuit coordinates with the KdpDE two component networks to regulate the capsular polysaccharide production in S. aureus