| Title: | Pheromone independent unisexual development in Cryptococcus neoformans |
| Author(s): | Gyawali R; Zhao Y; Lin J; Fan Y; Xu X; Upadhyay S; Lin X; |
| Address: | "Department of Biology, Texas A&M University, College Station, United States of America" |
| DOI: | 10.1371/journal.pgen.1006772 |
| ISSN/ISBN: | 1553-7404 (Electronic) 1553-7390 (Print) 1553-7390 (Linking) |
| Abstract: | "The fungus Cryptococcus neoformans can undergo a-alpha bisexual and unisexual reproduction. Completion of both sexual reproduction modes requires similar cellular differentiation processes and meiosis. Although bisexual reproduction generates equal number of a and alpha progeny and is far more efficient than unisexual reproduction under mating-inducing laboratory conditions, the alpha mating type dominates in nature. Population genetic studies suggest that unisexual reproduction by alpha isolates might have contributed to this sharply skewed distribution of the mating types. However, the predominance of the alpha mating type and the seemingly inefficient unisexual reproduction observed under laboratory conditions present a conundrum. Here, we discovered a previously unrecognized condition that promotes unisexual reproduction while suppressing bisexual reproduction. Pheromone is the principal stimulus for bisexual development in Cryptococcus. Interestingly, pheromone and other components of the pheromone pathway, including the key transcription factor Mat2, are not necessary but rather inhibitory for Cryptococcus to complete its unisexual cycle under this condition. The inactivation of the pheromone pathway promotes unisexual reproduction despite the essential role of this pathway in non-self-recognition during bisexual reproduction. Nonetheless, the requirement for the known filamentation regulator Znf2 and the expression of hyphal or basidium specific proteins remain the same for pheromone-dependent or independent sexual reproduction. Transcriptome analyses and an insertional mutagenesis screen in mat2Delta identified calcineurin being essential for this process. We further found that Znf2 and calcineurin work cooperatively in controlling unisexual development in this fungus. These findings indicate that Mat2 acts as a repressor of pheromone-independent unisexual development while serving as an activator for a-alpha bisexual development. The bi-functionality of Mat2 might have allowed it to act as a toggle switch for the mode of sexual development in this ubiquitous eukaryotic microbe" |
| Keywords: | "Calcineurin/genetics/metabolism Cryptococcus neoformans/genetics/*growth & development Fungal Proteins/genetics/metabolism *Genes, Mating Type, Fungal Mating Factor/genetics/*metabolism Reproduction, Asexual Spores, Fungal/genetics/growth & development Tr;" |
| Notes: | "MedlineGyawali, Rachana Zhao, Youbao Lin, Jianfeng Fan, Yumeng Xu, Xinping Upadhyay, Srijana Lin, Xiaorong eng R01 AI097599/AI/NIAID NIH HHS/ 2017/05/04 PLoS Genet. 2017 May 3; 13(5):e1006772. doi: 10.1371/journal.pgen.1006772. eCollection 2017 May" |
