Usv101 is a key regulator of cryptococcal virulence and determinant of host response

Cryptococcus neoformans is a fungal pathogen responsible for hundreds of thousands of deaths per year. Its critical virulence factor is a polysacharride capsule which grows large upon entry into a mammalian host. We previously identified USV101 as a transcription factor whose deletion results in enlarged capsules. Here, we characterize strains lacking or overexpressing USV101 in terms of their virulence-related phenotypes, the altered course of infection by them and immune response to them in a mouse model, the relationship of Usv101 to other transcription factors involved in capsule regulation, and the changes in Usv101 activity during capsule induction. To study the function of Usv101, a key C. neoformans regulator of virulence, and its interactions with downstream capsule-regulating TFs GAT201 and SP1, expression profiles were generated by RNA-seq of a usv101 deletion mutant, a USV101 overexpression mutant, strains expressing GAT201 under various promoters, various double mutants, and wildtype cells grown in a capsule non-inducing condition, a capsule inducing condition for 90 minutes, or a capsule inducing condition for 24 hours.