Discovering the xylan-sensing pathway in the filamentous fungus Neurospora crassa

发现丝状真菌粗糙脉孢菌中的木聚糖传感途径

• 批准号: 9039464
• 负责人: Lori B Huberman
• 金额: $ 5.61万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9039464
• 关键词: Animals; Biological; Carbohydrates; Carbon; Cell Wall; Cells; Cellular biology; Cleaved cell; Complex; Diabetes Mellitus; Directed Molecular Evolution; Disaccharides; Disease; Drug resistance; Enzymes; Eukaryota; Genes; Genetic; Genetic Transcription; Glucose; Goals; Human; Infection; Learning; Light; Malignant Neoplasms; Mammals; Maps; Metabolic; Methods; Microbe; Modeling; Molds; Molecular; Monosaccharides; Mutate; Mutation; Neurospora crassa; Nutrient; Obesity; Organism; Pathway interactions; Plant Components; Plants; Polysaccharides; Production; Proteins; Regulation; Regulon; Resources; Role; Saccharomyces cerevisiae; Saccharomycetales; Scanning; Scheme; Signal Pathway; Signal Transduction; Source; Sucrose; Techniques; Time; Transcriptional Regulation; Transgenic Organisms; Work; Xylans; Yeast Model System; Yeasts; cell growth; design; detection of nutrient; drug sensitivity; fungus; glucose uptake; hemicellulase; improved; interest; mutant; promoter; public health relevance; response; screening; sugar; synthetic biology; tool; transcription factor; tumor progression

 DESCRIPTION (provided by applicant): Identifying and utilizing the nutrients available in the most efficient manner is a challenge common to all organisms. In humans inaccurate or failed nutrient sensing can result in a variety of diseases including diabetes and obesity, and cancer progression has been shown to rely on increased glucose uptake and changes in nutrient sensing. Many of the nutrient sensing pathways are conserved from yeast to humans, and studies on nutrient sensing in unicellular eukaryotes have been instrumental in elucidating nutrient sensing pathways in humans. However, much of the work on nutrient signaling in unicellular eukaryotes has been done in budding yeast, which has a fairly limited carbohydrate utilization repertoire. Unlike budding yeast, the model filamentous fungus, Neurospora crassa, is capable of utilizing a wide variety of carbohydrates: from simple sugars to the complex sugar chains found in plant cell walls. In order to efficiently exploit the available resources, N. crass must be capable of sensing and responding to the presence of these different carbohydrates. Several transcription factors have been identified in N. crassa that activate the transcription of plant cell wall-degrading enzymes. One of these is XLR1, which activates the transcription of hemicellulases when in the presence of the plant cell wall component xylan. However, while it seems evident that XLR1 must be activated in order to induce expression of hemicellulases, the method by which this is achieved is still unclear. The goal of this project is to identify and characterize upstream regulators of XLR1 and their interactions with other nutrient sensing pathways in N. crassa, which will be accomplished through the completion of the following three specific aims. The first is to screen for mutants in which XLR1 activation is either constitutive o uninducible to identify the genes involved in the xylan-sensing pathway and characterize their function and role in xylan sensing. The second aim is to use directed evolution to probe more subtle genetic interactions both within the xylan-sensing pathway and between the xylan-sensing pathway and other nutrient sensing pathways to identify mutations which optimize N. crassa for rapid and accurate xylan sensing and utilization as well as to understand how the xylan-sensing pathway fits into the larger scheme of pathways that assess the metabolic state of the cell. And the third aim is to use synthetic biology to reconstruct the xylan-sensing pathway in the budding yeast, Saccharomyces cerevisiae, which is not able to use xylan as a carbon source, using the optimized genes identified in the first two aims to validate the identification o genes involved in the xylan-sensing pathway. The completion of these aims should shed light on the xylan-sensing pathway in N. crassa and its interaction with other cellular signaling pathways. We expect this to improve our overall understanding of cellular signaling throughout the eukaryotic realm , since scanning the diversity of molecular mechanisms involved in signaling pathways is helpful in elucidating broad biological paradigms.

 描述（由适用提供）：以最有效的方式识别和利用可用的营养是所有组织共有的挑战。在人类中，营养感应不准确或失败会导致多种疾病，包括糖尿病和肥胖症，癌症的进展已被证明依赖于增加的葡萄糖摄取和营养感应的变化。从酵母到人类，许多营养感应途径都是保守的，并且对单细胞真核生物中的营养敏感性的研究一直在阐明人类的营养敏感性途径中发挥了作用。然而，在酵母中，在单细胞真核生物中进行营养信号传导的大部分工作是在酵母中进行的，酵母的碳水化合物利用率相当有限。与芽酵母不同，模型的丝状真菌神经孢子骨能够利用多种碳氢化物：从简单的糖到在植物细胞壁中发现的复杂糖链。为了有效地探索可用资源，N。Crass必须能够敏感并响应这些不同的碳水合物的存在。在Crassa乳杆菌中已经鉴定出了几种转录因子，这些因子激活了植物细胞壁降解酶的转录。其中之一是XLR1，它在存在植物细胞壁成分Xylan时激活半纤维素酶的转录。但是，尽管似乎必须激活XLR1才能诱导半细胞酶的表达，但仍不清楚的方法仍然尚不清楚。该项目的目的是识别和表征XLR1的上游调节剂及其与N. Crassa中其他营养感应途径的相互作用，这将通过完成以下三个特定目的完成。首先是筛选突变体，其中XLR1激活是不可诱导的构型O可以识别Xylan传感途径所涉及的基因，并表征其在Xylan传感中的功能和作用。 The second aim is to use directed evolution to probe more subtle genetic interactions both within the xylan-sensing pathway and between the xylan-sensing pathway and other nutrient sensing pathways to identify mutations which optimize N. crassa for rapid and accurate xylan sensing and utilization as well as to understand how the xylan-sensing pathway fits into the larger scheme of pathways That assess the metabolic state of the cell.第三个目的是使用合成生物学重建Xylan感应途径 在发芽的酵母中，使用前两个目的鉴定的优化基因来验证Xylan sensing途径中涉及的鉴定O基因。这些目的的完成应阐明N. Crassa中的Xylan感应途径及其与其他细胞信号通路的相互作用。我们预计这将提高我们对整个真核领域的细胞信号传导的总体理解，因为扫描与信号通路有关的分子机制的多样性有助于阐明广泛的生物学范式。