This proposal is targeted at understanding the roles of mRNA methylation and long non-coding RNA, which are two molecular mechanisms of gene regulation, in Candida albicans virulence. C. albicans is a normally benign commensal, but can cause skin and mucosal membrane infections in healthy individuals, and life threatening systemic infections in susceptible individuals. C. albicans pathogenicity is linked to its ability o switch from growing in yeast-form cells to growing in filament and biofilm forms. While it cannot reproduce sexually, C. albicans can generate genetic diversity by mating, which has the potential to result in increased virulence and drug resistance. A better understanding of the molecular mechanisms behind these processes is required in order to identify new therapeutic avenues. mRNA methylation has been discovered decades ago, but the large scale of this modification in other eukaryotes has only recently became apparent, and its function in gene regulation is not yet understood. In Saccharomyces cerevisiae, IME4 encodes an mRNA methyltransferase, which plays a regulatory role in S. cerevisiae meiosis and filamentation. An IME4 homologue is present in C. albicans. Long non-coding RNA (lncRNA) are large transcripts that participate in gene regulation but do not encode any protein. S. cerevisiae IME4 expression is regulated by an antisense lncRNA, and this form of regulation appears to be conserved in C. albicans. Preliminary data indicates that mRNA methylation occurs in C. albicans, and that IME4 is expressed under filamentation inducing conditions. Furthermore, overexpression of IME4 inhibits filamentation. Using molecular genetics coupled with high throughput RNA sequencing, the proposed research will identify C. albicans IME4 mRNA targets, assess its role in mating, filamentation and biofilm formation, and study its regulation by lncRNA.
Candida albicans is a fungal human pathogen that kills susceptible individuals. This proposal will investigate the role of two conserved but not well-understood mechanisms of gene regulation in the pathogenicity of this fungus.