How does MaoP impact biofilm formation?

Bacteria form biofilms which are aggregated communities of cells that represent the most common mode of life for most species. Biofilms are important as bacteria in a biofilm are very hard to kill with antibiotics and biofilms play a role in most bacterial infections. We also make positive use of biofilms in biotechnology to produce important chemicals and drugs. We know forming a biofilm involves large scale changes to gene and protein production within a bacterial population but not all the details of how this is regulated are well characterised. Understanding how bacteria control the pathways needed to form a biofilm is a fundamentally important goal for microbiology and is needed to develop interventions to prevent biofilm associated infections and to improve biofilm formation in bioprocessing. Recently we discovered a novel and important role for a protein, MaoP in impacting biofilm formation in both E. coli and Salmonella. MaoP was identified in whole genome screens looking for genes important in biofilm formation in both species. We have subsequently confirmed that MaoP has a major role in biofilm formation by making defined mutants lacking, or over-expressing MaoP. Very little is currently known about the function of MaoP which was originally named as being identified as impacting chromosome (macro organisation) structure although no mechanistic basis was proposed. In our preliminary work we have found that changing levels of MaoP within the cell changes expression of components of the biofilm extracellular matrix – a selection of large molecules secreted by the cell which helps cells adhere and provides protection. We also saw changes in the levels of cyclic-di-GMP (c-di-GMP) within the cell. C-di-GMP is a molecule known to be a key regulator of biofilm formation in many species. Recent work by other groups has also identified that MaoP is an RNA binding protein although no details of specific targets have been characterized to date. Given our preliminary data and that in the literature we have developed the hypothesis that: ‘MaoP impacts formation of the biofilm matrix by influencing intracellular levels of c-di-GMP’ We will test this hypothesis by addressing four main objectives: To identify where and when in biofilm formation MaoP impacts c-di-GMP levels within cells. To understand how MaoP interacts with known c-di-GMP turnover proteins. To identify when during the biofilm lifecycle MaoP is expressed and its location within biofilms and within cells. To determine how conserved the identified mechanisms of MaoP action are across other Enterobacteriaceae. Together the outputs will provide a better understanding of biofilm formation in important species as well as giving an evidence base which could be later exploited to alter biofilm formation.