Characterization of the diadenylate cyclase DisA in the bacterium Clostridium difficile
Undergraduates: Emily Peluso, Elizabeth Garrett Danielle Fortune, Ph.D.
Faculty Advisor: Rita Tamayo
Department: Biology
The intestinal pathogenic bacterium, Clostridium difficile, is a Gram-positive, spore-forming, obligate anaerobe. It is currently classified as an urgent public health threat by the Centers for Disease Control and is a major cause of fatal nosocomial infections in the United States. Due to the high recurrence rate of C. difficile infected patients, C. difficile virulence factors have become especially important to study. C-di-AMP has been shown to regulate diverse processes in many bacterial organisms. Specifically, it was shown that c-di-AMP levels are modulated in Bacillus subtilis by the diadenylate cyclase DisA. Changes in c-di-AMP in B. subtilis controls sporulation progression. Since C. difficile encodes a DisA ortholog, we hypothesize that c-di-AMP may play a role in regulating sporulation in C. difficile. To study the role that c-di-AMP plays in sporulation, we generated a disA mutant and observed the phenotypic effects in vitro and in vivo. We found that in vivo bacterial colonization is attenuated in the disA mutant compared to wild-type. However, no significant difference was observed in late-stage sporulation genes in the disA mutant compared to wild-type by qRT-PCR. Taken together, these results suggest that disA is important for establishing infection. Future studies include evaluating early sporulation genes and assessing the role of disA in sporulation and germination in vitro.