msaABCR operon positively regulates biofilm development by repressing proteases and autolysis in Staphylococcus aureus.
Staphylococcus aureus is an important human pathogen that causes nosocomial and community-acquired infections. One of the most important aspects of staphylococcal infections is biofilm development within the host, which renders the bacterium resistant to the host's immune response and antimicrobial agents. Biofilm development is very complex and involves several regulators that ensure cell survival on surfaces within the extracellular polymeric matrix. Previously, we identified the msaABCR operon as an additional positive regulator of biofilm formation. In this study, we define the regulatory pathway by which msaABCR controls biofilm formation. We demonstrate that the msaABCR operon is a negative regulator of proteases. The control of protease production mediates the processing of the major autolysin, Atl, and thus regulates the rate of autolysis. In the absence of the msaABCR operon, Atl is processed by proteases at a high rate, leading to increased cell death and a defect in biofilm maturation. We conclude that the msaABCR operon plays a key role in maintaining the balance between autolysis and growth within the staphylococcal biofilm.
Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406-0001, USA.
Gyan S
GS
Sahukhal
Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406-0001, USA.
Justin L
JL
Batte
Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406-0001, USA mohamed.elasri@usm.edu.
Mohamed O
MO
Elasri
D001433:Bacteriolysis; D018441:Biofilms / Q000254:growth & development*; D015964:Gene Expression Regulation, Bacterial; D018613:Microscopy, Confocal; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics; D009876:Operon / Q000235:genetics; D010447:Peptide Hydrolases / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017384:Sequence Deletion; D013211:Staphylococcus aureus / Q000235:genetics / Q000502:physiology*
D010447:Peptide Hydrolases; D009238:N-Acetylmuramoyl-L-alanine Amidase
Staphylococcus aureus; autolysis; biofilm; msaABCR; proteases; regulation