TRANSCRIPTIONAL REGULATION ANALYSIS OF PrtA METALLOPROTEASE AND LipBCD TRANSPORTER IN Serratia marcescens

ROBERTO E. BRUNA; JAVIER FERNANDO MARISCOTTI; ELEONORA GARCÍA VÉSCOVI

Rosario

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

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular - SAIB

Serratia marcescens is an enteric bacterium that can function as an opportunistic pathogen within immunocompromised hosts. Despite reiterative reported S. marcescens infections, its virulence mechanisms are poorly understood. Part of Serratia?s pathogenic potential may be attributed to the large number of secreted exoenzymes, including chitinases, phospholipase, hemolysin, nuclease and proteases, including the metalloprotease PrtA which is produced in our clinical strain. Recent studies showed that PrtA is secreted by the LipBCD transporter, and point to this enzyme as an important virulence factor in different models of infections, including cell line cultures, insects and mouse. However, little is known about environmental signals and regulatory factors that modulate its production. In this work, we have assessed the regulation of prtA and lipBCD using lacZ- and gfp-containing reporter plasmids. Results showed that PrtA expression is induced during the stationary growth phase, and is also temperature dependent being levels of prtA-lacZ fusion five times higher at 30°C than at 37°C. Moreover, poor aireation of the medium impaired transcription from the reporter systems, at either temperature. Bioinformatic analyses revealed consensus sequence for the recognition of the the response regulator of the Rcs phosphorelay, RcsB, in the prtA and lipBCD promoter regions.