Understanding the Role of Mat2 in the Sexual Development of Cryptococcus neoformans
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Sexual reproduction is conserved and maintained in all major eukaryotic lineages. The fungus Cryptococcus neoformans is known to undergo a-α bisexual mating and also unisexual mating, with bisexual mating being far more efficient under laboratory conditions. During bisexual mating, the mating types of the progeny are segregated in the Mendelian fashion, with half of the progeny inheriting the mating type a and the other half inheriting the mating type α. However, MATα dominates in the environment as well as in the clinical settings. Given that similar factors such as pheromone and environmental conditions are known to stimulate both unisexual and bisexual mating, it is unknown how and when C. neoformans chooses one mode of reproduction over the other. One important event that takes place during sexual development is the transmission of parental mitochondrial DNA. During bisexual reproduction between isogamic a and α cells, most of the progeny inherit the mitochondrial DNA from only the a parent. How this eukaryotic microbe selects and preserves only one parental mitochondrial DNA is unclear. Here, we have identified a key transcription factor Mat2 as the prezygotic decision maker for the transmission of mitochondrial DNA to the progeny. Mat2 also cooperates with postzygotic control to ensure tight uniparental mitochondrial DNA inheritance during bisexual mating. Although Mat2 is absolutely critical for bisexual mating, our studies indicate that the absence of Mat2 (or under conditions when Mat2 is repressed) promotes C. neoformans cells to undergo unisexual development. Thus, the findings of this study advanced our understanding of the regulation of different developmental trajectories by genetic and environmental factors.
Gyawali, Rachana (2016). Understanding the Role of Mat2 in the Sexual Development of Cryptococcus neoformans. Doctoral dissertation, Texas A & M University. Available electronically from