Identifying the endoreplication pathway in Cryptococcus neoformans
Aaliyah Davy Mentors: Ci Fu, PhD., Joseph Heitman, MD., PhD. Department of Molecular Genetics and Microbiology
Cryptococcus neoformans is an opportunistic fungal pathogen that affects the immunocompromised and rarely, the immunocompetent. The fungus has two different sexual cycles- that is, bisexual and unisexual. Central to bisexual reproduction is cell and nuclear fusions that are indicative of ploidy duplication and the yeast-hyphal morphology transition. In this study, we investigated the currently unidentified endoreplication cycles that these cells go through to attain ploidy replication in the unisexual cycle. We hypothesized that one of six cell cycle genes we have chosen, that have differential expression throughout unisexual reproduction, will have some impact on the pathway. To test this, we generated gene deletion constructs with dominant selectable marker neomycin (G418), and conducted biolistic transformation on the unisexual strain XL280α. Transformants were streaked on additional G418 plates and verified by PCR. We tested whether deletion of these genes impact unisexual reproduction. This endoreplication pathway has also been linked to the formation of titan cells (greatly enlarged versions of the pathogen) in host infection, so we tested the significance of these genes in titan cell formation as well.
