Domain characterization of the blue light regulators Cwc1 and Cwc2 in Cryptococcus neoformans
Date Issued
2007
Date
2007
Author(s)
Su, Bei-Jia
DOI
zh-TW
Abstract
Light regulates growth, physiolophy and differentiation in various organisms including fungi. Fungi usually perceive light within a particular region of radiant energy spertrum. One of the most widesperead and pronounced phenomena in fungi is the blue light photoresponses. Cryptococcus neoformans, a heterothallic basidiomycetous fungus, primarily infects the immunocompromised individuals. Under nitrogen limitation conditions, strains of opposite mating types, MATa and MATα, produce conjugation tubes and fuse to form dikaryotic filaments, and subsequently produce the basidia and meiotic progeny basidiospores to complete its sexual cycle. Our previous studies have demonstrated that the production of sexual dikaryotic filaments is inhibited by blue light via the Cwc1 (C. neoformans WC-1) and Cwc2 (C. neoformans WC-2) proteins, homologues of Neurospora crassa WC-1 and WC-2. The deduced Cwc1 amino acid sequence contains a specialized chromophore binding domain known as LOV (for Light-Oxygen-Voltage) domain, two putative PAS (Per-Arnt-Sim) domains, and a putative nuclear localization sequence (NLS). A putative PAS domain and GATA-type zinc finger DNA-binding motif were also identified in the Cwc2 protein. To confirm the roles of putative domains and also identify regions important for the Cwc1 and Cwc2 function, a series of partially deleted CWC1 and CWC2 genes under the constitutively expressed C. neoformans GPD1 promoter were generated in this study. These constructs were transformed into the MATα wild-type, cwc1 and cwc2 mutant strains and sexual filamentation and other phenotypes were examined and compared under light and dark conditions. Our results showed that LOV domain, PAS domains, and the region containing the NLS are crucial for the function of Cwc1 protein, and PAS domain and GATA-type zinc finger DNA-binding motif are also required for the proper execution Cwc2 protein. In addition, regions important for the CWC proteins were also identified. In this study, we used C. neoformans as a model to dissect the blue light photoregulation. To the end, we hope to reveal the functional domains important for the evolutionally conserved blue light regulators in the basidomycetous fungi.
Subjects
隱球菌
藍光光反應
藍光接收器
紅色麵包黴
Cwc1
Cwc2
LOV功能區塊
PAS功能區塊
NLS序列
Cryptococcus neoforman
blue light photoresponses
blue light regulators
Neurospora crassa
LOV domain
PAS domains
NLS
Type
other