Characterization of quorum sensing regulated small RNAs in Pseudomonas aeruginosa


Fellow: Maureen Thomason, PhD

Mentor:  Pete Greenberg, PhD
Professor, Microbiology


In the last decade, it has become apparent that small regulatory RNAs (sRNAs) facilitate the adaptation of bacteria to a variety of environmental niches through post-transcriptional regulation of target mRNAs. Environmental signals such as nutrient and oxygen deprivation, membrane stress and quorum sensing signaling molecules can induce sRNA mediated gene regulation leading to dramatic alterations in the transcriptional profile of a bacterium. Acute infections of the cystic fibrosis (CF) lung by Pseudomonas aeruginosa are associated with secretion of virulence factors, many of which are regulated by quorum sensing control pathways that enable establishment of an infection. As chronic infections persist, the secretion of virulence factors is reduced and the ability of P. aeruginosa to form biofilms increases, a process controlled by sRNAs in other bacteria. Therefore, it is likely there are sRNAs under quorum control, which may be involved in mediating and altering the transcriptional profile of P. aeruginosa facilitating its ability to colonize and adapt to the CF lung. The work described here will elucidate the function of the quorum sensing regulated sRNAs, Lsr1 and Lsr2, and identify additional sRNAs under quorum control. This work will generate a fundamental base of knowledge for quorum sensing regulated sRNAs, which can then be studied and examined further in CF lung infection models. Understanding these regulons and the roles they play in the ability of P. aeruginosa to infect and colonize the lungs of CF patients may lead to the identification of new targets and therapeutic treatments for CF.