Dissection of the Cryptococcus neoformans light response and characterization of Cryptococcus neoformans SSN8 homologue
Date Issued
2007
Date
2007
Author(s)
Lin, Yu-Sheng
DOI
zh-TW
Abstract
Cryptococcus neoformans is an important human fungal pathogen. In our previous investigation, we demonstrated that blue light negatively regulates the sexual filamentous growth via the Cwc1/Cwc2 complex in C. neoformans. To further understand how light inhibits mating filamentation, we conducted a suppressor screening using Agrobacterium-mediated insertional mutagenesis to identify the components interacting with or downstream of the Cwc complex under the CWC1 overexpression strain background. Among 4132 nourseothricin-resistant transformans screened, we identified 64 strains restored different levels of mating filamentation. The sites of T-DNA integration among 21 transformans were recovered. One strain, AZ5, restored the highest level of filamentation was observed and that T-DNA was found to be inserted at the 5’-UTR region of the CWC2 gene. The finding of CWC2 gene in the screen validates our approach. In this study, we further characterized the transformant AY18 in which T-DNA integration affected the activity of a gene homologous to the Saccharomyces cerevisiae SSN8. In budding yeast, SSN8 gene, also named SRB11/UME3/CYCC/RYE2, has been demonstrated to play diverse roles in sugar utilization, meiosis, cell phase control, and transcription regulation. To reveal the roles of SSN8 gene in C. neoformans, we generated the ssn8 mtant, reconstituted strain, and overexpression strain under the wild-type background. The mutant phenotypes included slightly reduced mating filamentation, extensive haploid filamentation, increased melanin accumulation, changed cellular morphology and production of invasive hyphae under rich YPD growth condition. Our results suggest that C. neoformans SSN8 homologue plays critical roles in the diverse physiological and differentiation processes. This is the first demonstration of mediator component in C. neoformans. Its roles related to the Cwc complex remain to be further investigated.
Subjects
隱球菌
藍光反應
CWC1
CWC2
SSN8同源基因
mediator complex
Cryptococcus neoformans
blue light response
Agrobacterium random insertional mutagenesis
suppressor screen
SSN8 homologue
mediator complex.
Type
other
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