Insertional mutagenesis combined with an inducible filamentation phenotype reveals a conserved STE50 homologue in Cryptococcus neoformans that is required for monokaryotic fruiting and sexual reproduction
Article first published online: 23 DEC 2010
© 2010 Blackwell Publishing Ltd
Volume 79, Issue 4, pages 990–1007, February 2011
How to Cite
Fu, J., Mares, C., Lizcano, A., Liu, Y. and Wickes, B. L. (2011), Insertional mutagenesis combined with an inducible filamentation phenotype reveals a conserved STE50 homologue in Cryptococcus neoformans that is required for monokaryotic fruiting and sexual reproduction. Molecular Microbiology, 79: 990–1007. doi: 10.1111/j.1365-2958.2010.07501.x
- Issue published online: 8 FEB 2011
- Article first published online: 23 DEC 2010
- Accepted manuscript online: 17 DEC 2010 07:20AM EST
- Accepted 4 December, 2010.
Cryptococcus neoformans typically grows in a yeast-like morphology; however, under specific conditions the fungus can produce hyphae that are either dikaryotic or monokaryotic. In this study, we developed a simple method for inducing robust monokaryotic fruiting and combined the assay with Agrobacterium tumefaciens insertional mutagenesis to screen for hyphal mutants. A C. neoformans homologue of the Saccharomyces cerevisiae STE50 gene was identified and characterized. STE50 was found to be required for sexual reproduction and monokaryotic fruiting. Ste50p has conserved SAM and RA domains, as well as two SH3 domains specific to basidiomycetous Ste50 proteins. Analysis of protein–protein interaction showed that Ste50p can interact with Ste11p and Ste20p, and epistasis experiments placed STE50 between STE20 and STE11. Genetic analysis of the role of STE50 in sexual reproduction showed that it was required for all steps, from response to pheromone to production of hyphae. Analysis of the effect of individual Ste50p domains on sexual reproduction and monokaryotic fruiting revealed domain-specific effects for both processes. This study revealed that the C. neoformans STE50 gene has both conserved and novel functions during sexual reproduction and monokaryotic fruiting, and these functions are domain-dependent.