Abstract
摘要:生物能因應各種環境的變化,調整本身的生理狀態。在自然環境中,光為一重要的環境因子,除了為能量來源,光線的變化也調控自然界中各種生物的生長及發育。在真菌光反應的研究中,Neurospora crassa為主要的研究模式,N. crassa可感受藍光,藍光調控其無性及有性之產孢過程,並且亦為其生物週期重要環境影響因子之一。在N. crassa的研究中得知,wc-1及wc-2基因為N. crassa光反應主要之調控因子,2002年發表於”科學”雜誌期刊之兩篇報導,更進一步被証實WC-1為其藍光的光接受器,此乃真菌第一個被證實之光反應接受器。隱球菌(Cryptococcus neoformans),為一伺機性人體病原真菌,已具完備的分子生物學研究系統,加上已完成之基因體計劃,其已發展為真菌致病性、生理及發生學分子調控機制之模式生物。隱球菌有性生殖之費洛蒙調控制之研究中,吾人發現隱球菌有性生殖雙核菌絲之形成與生長,受光線抑制。在本計畫93年度執行期間,吾人已界定隱球菌只可感受可見光譜中之藍光,為進一步探討隱球菌光反應之分子調控機制,吾人於隱球菌中找到N. crassa wc-1及wc-2之同
Abstract: All organisms must respond to environmental stimuli and make appropriate physiological adjustments. Light is an important environmental signal and has profound effects on living creatures. Light not only is the major source of energy on Earth, and the fluctuation of light also regulates the growth and differentiation of many organisms. In fungi, Neurospora crassa has been the leading model for studying the molecular mechanisms of blue light photobiology. Blue light regulates asexual and sexual sporulation process, and also acts as a signal to entrain the circadian rhythm. In N. crassa, wc-1 and wc-2 genes are the central regulators of the blue light responses and all light responses are lost in these two mutants. In 2002, two articles published in “Science” demonstrated that WC-1 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. Studies of the C. neoformans genes involved in the mating process, we observed that production of the dikaryotic filaments during the mating process is influenced by light. In studies supported by NSC in 2004, we determined that C. neoformans also perceive blue light in the visible light spectrum. To further dissect the molecular mechanisms of blue light responses in C. neoformans, we have identified the N. crassa wc-1 and wc-2 homologues in the C. neoformans genome and named the genes CWC1 and CWC2 respectively. To dissect their roles in C. neoformans, we have made the cwc1 and cwc2 gene deletion mutants and demonstrated that they both involve in the regulation of photoresponse in C. neoformans. Parts of the works have published in the Journal “Molecular Microbiology (2005) 56: 480-491” (SCI, Impact factor 5.959). Interestingly, Cwc1 and Cwc2 have also been shown to contribute to the virulence of this human fungal pathogen by a research group at Duke University. The proposed study is to further dissect the molecular mechanisms regulated by Cwc1 and Cwc2, and identify the interacting proteins and downstream targets of light response pathway in C. neoformans. Specific aims include: 1). identify other downstream targets of Cwc1 and Cwc2 in the light responses by suppressor screening; 2). conduct the genome wide mcroarray analyses to determine how light negatively regulates the production of mating filaments and how Cwc proteins are involved in the regulation of virulence; 3). identify the interacting proteins of Cwc1 and Cwc2 by immuno-coprecipitation experiments To the end, we hope to understand how blue light negatively regulates the filamentation and also how they contribute to the virulence of C. neoformans.
Keyword(s)
隱球菌
CWC1基因
CWC2基因
藍光光反應
分子機制
suppressor 篩選
微矩陣分析
免疫沉降分析
Cryptococcus neoformans
CWC1
CWC2
blue light photoresponse
molecular mechanism
suppressor screen
microarray analysis
immuo-coprecipitation