Role of Staphylococcus aureus SAOUHSC01313-1314 TCS in the susceptibility to stress factors

DIAZ, A. R.; DE MENDOZA, D; MANSILLA, MC

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

SAIB

Staphylococcus aureus (SA) is a pathogen that causes a multitude of different diseases. Stress factors act as host-specific signals for the pathogen, inducing the expression of virulence-related genes. Since two component systems (TCSs) are the principal mechanism involved in stress response, we studied two contiguous genes located in SA NCTC 8325, SAOUHSC01313-01314 coding for a histidine kinase (HKsa) and a response regulator (RRsa), respectively. These genes showed homology with Bacillus subtilis DesKR, which regulates des transcription at low temperature. The SA TCS is located upstream of genes SAOUHSC01311-01312, encoding a putative ABC transporter that carries in its promoter a regulatory box similar to that of des. This TCS/ABC link resembles the prototype detoxification module found in Firmicutes. In this work we investigated the SA TCS role in exposure to stressors. We constructed a SA mutant lacking the TCS and found that this strain became susceptible to ATB and low temperature. Additionally, we study transcriptional activation of the ABC transporter by HKsa-RRsa by performing b-galactosidase assays of strains carrying a transcriptional fusion of SAOUHSC01311 promoter to lacZ.  Transcription of Psa01311-lacZ is activated at 25°C in the presence of milk components. These results suggest that SA TCS is important for bacteria fitness when they are exposed to membrane stressors