REGULATION OF FILAMENTOUS GROWTH IN YEAST

酵母丝状生长的调节

• 批准号: 6479011
• 负责人: Haoping Liu
• 金额: $ 27.58万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6479011
• 关键词: Candida albicans; DNA binding protein; Saccharomyces cerevisiae; biological signal transduction; cell cycle; cell growth regulation; cell morphology; cyclic AMP; fungal genetics; fungal proteins; gene deletion mutation; gene expression; genetic promoter element; genetic regulation; genetic regulatory element; immunoprecipitation; mass spectrometry; microarray technology; mitogen activated protein kinase; point mutation; protein localization; transcription factor; yeasts

Candida albicans is one of the most frequently isolated fungal pathogens of humans. It can undergo reversible morphogenetic transitions among budding yeast, pseudohyphal, and hyphal growth forms. Its unique ability to switch from yeast to hyphal growth in response to various environmental signals not only is inherent to its pathogenicity, but also provides an excellent paradigm to understand how signaling pathways coordinate growth and development. The objectives of this research are to understand how various signaling pathways are integrated to control the expression of a common set of hypha- specific genes, and the molecular connection between the signaling pathways and cell morphogenesis. There are three Aims: 1) Identification of downstream effectors of filamentation signaling pathways that are responsible for hyphal morphogenesis in C. albicans. Differential gene expression studies with C. albicans DNA arrays will be performed to identify changes in gene expression associated with morphological differentiation as well as regulated by filamentation signaling pathways. Functional studies of the genes identified from the array experiments will be carried out to address whether any newly identified genes are responsible for hyphal morphogenesis. 2) Mechanisms of transcriptional integration at the promoters of hypha-specific genes in C. albicans. A combination of DNA binding experiments and functional assays using site-specific mutations in the promoter of a selected hypha-specific gene will be used to address whether the terminal transcription factors of a MAP kinase pathway and the cAMP pathway act directly on the promoter, and whether they act cooperatively with each other, or with yet unidentified components on the promoter. In addition, upstream DNA sequences of hypha-specific genes from Aim 1 will be used to predict and identify novel cis-elements and their binding proteins. 3) Regulation and function of Ste12 in S. cerevisiae. Ste12 is the terminal transcription factor of the MAP kinase pathways required for mating, invasive growth and pseudohyphal growth in S. cerevisiae. Both biochemical and genetic experiments are proposed to identify novel regulators of Ste12. Additional DNA array experiments will be used to determine the molecular connections between Ste12 activation and cell elongation.

白色念珠菌是人类最常见的真菌病原体之一。它可以在发芽酵母、假菌丝和菌丝生长形式之间经历可逆的形态发生转变。它独特的从酵母到菌丝生长的能力响应各种环境信号，不仅是其致病性所固有的，而且也为理解信号通路如何协调生长和发育提供了一个很好的范例。本研究的目的是了解不同的信号通路如何整合来控制一组共同的菌丝特异基因的表达，以及这些信号通路与细胞形态发生之间的分子联系。有三个目的：1)鉴定在白念珠菌中负责菌丝形态发生的丝状信号通路的下游效应分子。利用白念珠菌DNA阵列进行差异基因表达研究，以确定与形态分化相关的基因表达变化以及丝状信号通路的调节。将对从阵列实验中鉴定的基因进行功能研究，以确定是否有任何新鉴定的基因与菌丝形态发生有关。2)白念珠菌菌丝特异基因启动子转录整合的机制。结合DNA结合实验和利用选定的菌丝特异基因启动子的定点突变进行的功能分析，将被用来研究MAPK途径和cAMP途径的末端转录因子是否直接作用于启动子，以及它们是相互协同作用，还是与启动子上的未知成分作用。此外，来自AIM 1的菌丝特异基因的上游DNA序列将被用于预测和鉴定新的顺式元件及其结合蛋白。3)STE12在酿酒酵母中的调控和功能。STE12是酿酒酵母交配、侵袭生长和假菌丝生长所需的MAP激酶通路的末端转录因子。生化和基因实验都被用来确定STE12的新调控因子。其他DNA阵列实验将用于确定STE12激活和细胞伸长之间的分子联系。