2004-08-012024-05-16https://scholars.lib.ntu.edu.tw/handle/123456789/667460摘要：生物為了生存，必須根據環境的變化，改變本身的生理狀態。在各種環境因子中， 光是很重要的一項，光除了是能量來源，光線的變化也調控自然界中各式生物的生長及 發育。在真菌光反應的研究中，以Neurospora crassa 當作真菌研究的模式生物。N. crassa 只可感受藍光， 藍光除了調控產胞外， 還會調控菌絲合成類胡蘿蔔素， 促進 protoperithethia 的形成，以及子囊殼頸的向光性。在N. crassa，white collar 1 及white collar 2 兩種變異株失去所有受藍光誘導之反應，因此wc-1 及wc-2 的基因產物被認為是N. crassa 光反應之主要因子。實驗証明，WC1 除了調控其他光反應基因外，2002 年發表 於”科學”雜誌期刊之兩篇報導，WC1 更進一步被証實是藍光的光接受器，此乃真菌第一 個被報導之光反應接受器。隱球菌(Cryptococcus neoformans)，為一伺機性人體病原真 菌，具良好的分子生物學研究系統，適合進行真菌致病性、生理及發生學之分子調控機 制之探討。於隱球菌有性生殖費洛蒙調控機轉之研究中，<br> Abstract: In order to survive, all organisms must make appropriate physiological adjustments in response to the environmental changes. Among the environmental factors, light has profound effects on lives. Light is the major resource of energy on earth, and the fluctuation of light also regulates the growth and differentiation of various organisms. In fungi, Neurospora crassa has been the model for studying the molecular mechanism of light responses. N. crassa only can sense blue light. During asexual sporulation, blue-light stimulates the formation of the conidial structures and influences the number of conidia production. During vegetative growth, blue-light induces the production of carotenoids and acts as a signal to entrain the circadian rhythm. During sexual differentiation, blue-light influences development of protoperithecia and the number of perithecia formed. Additionally, blue-light also stimulates positive phototropism of the perithecial beaks. In N. crassa, two mutants, white collar-1 (wc-1) and white collar-2 (wc-2), were known to be completely lost of all light responses. Therefore, their gene products have been thought to be the central regulators of the blue light responses in N. crassa. In 2002, two articles published in the “Science” Journal further experimentally demonstrated that WC-1 indeed is the blue light photoreceptor in N. crassa. This is the first photoreceptor identified in fungi. Cryptococcus neoformans is an opportunistic human fungal pathogen with well established molecular biology systems for studying the molecular mechanism of fungal pathogenesis, physiology and differentiation. We have found that the production and growth of the dikaryotic hyphae in the sexual cycle of C. neoformans is partially inhibited by light during the characterization of pheromone signaling. To further dissect the molecular mechanisms of light response in C. neoformans, we have used the amino acid sequence of N. crassa WC1 to blast against the C. neoformans genome and successfully identified the WC1 homolog in C. neoformans. Preliminary sequence analysis has revealed that C. neoformans WC1 also contains LOV, PAS domains, and nuclear localization sequence. However, zinc-finger DNA binding domain and transactivation domain are not found. To understand the role of WC1 homolog and the molecular mechanism regulating the light response in C. neoformans, we propose this two-year study. Four specific aims will be focused in the grant: First, we will determine the action spectrum of light response in C. neoformans. Second, we will characterize the C. neoformans WC1 gene and WC1 protein and determine if WC1 is also the photoreceptor. Third, we will conduct the functional analysis of C. neoformans WC1 gene. Finally, we hope to identify other components of light responses in C. neoformans. To the end, we are hoping to generate the molecular scheme of light response in C. neoformans.隱球菌WC1 基因光反應分子機制Cryptococcus neoformansWC1 genelight responsemolecular mechanism