Elucidation of a Dictyostelium chalone

盘基网柄菌查酮的阐明

基本信息

批准号：
8913213
负责人：
Richard H Gomer
金额：
$ 28.48万
依托单位：
TEXAS A&M UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2018-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8913213
关键词：
1-Phosphatidylinositol 3-Kinase Anion Exchange Resins Behavior Binding Biochemistry Biological Factors Biological Models Cancer Patient Cell Count Cell Cycle Cell Cycle Regulation Cell Density Cell Nucleus Cell Volumes Cells Cellular biology Cyclin B Cytosol Decision Making Development Developmental Biology Dictyostelium Dictyostelium discoideum Eukaryota G2/M Transition Gene Expression Profile Genes Genetic Genetic Screening Heating Human Lead Mitosis Modeling Molecular Natural Products Chemistry Normal Cell Null Lymphocytes Nutrient PTEN gene Pathway interactions Peptide Hydrolases Phosphoric Monoester Hydrolases Physics Proliferating Regulator Genes Resistance Shotguns Signal Transduction Signal Transduction Pathway Suspension Culture System Techniques Testing Theoretical model Tissues Work cell type chalone density extracellular homologous recombination insight mathematical model neoplastic cell prevent response serum sodium transport inhibitor small molecule transcription factor tumor

项目摘要

DESCRIPTION (provided by applicant): A fundamental but poorly understood question in developmental biology is how cells stop proliferating when the density of cells of that cell type, n a tissue or the entire body, reaches the correct point. Theoretically, one way this can be accomplished is if the cells secrete a specific diffusible factor that inhibits proliferation of tht cell type. The extracellular concentration of such a factor, called a chalone, would increase as the density of the secreting cells increase, and when the density of that cell type reaches the correct point, the corresponding high levels of the chalone would stop their proliferation. Despite evidence for the existence of chalones, little is known about the identity of chalones and their signal transduction pathways. In the simple eukaryotic model system Dictyostelium discoideum, cells stop proliferating when they reach a high cell density even if adequate nutrients are presen+t. This is due to the extracellular accumulation of a chalone. We have partially purified the chalone and found that it is a heat- and protease-resistant anionic molecule smaller than 2 kDa. The chalone signal transduction pathway involves the PTEN and CnrN phosphatases and the BzpN transcription factor, and blocks proliferation by preventing the transition from the G2 to the M phase of the cell cycle. I propose three specific aims that will use the power of the Dictyostelium model system to elucidate this chalone and its signal transduction pathway. First, we will finish the purification and identify the chalone, and test theoretical models of chalone function. Second, we will test the hypothesis that the chalone regulates the PI3 kinase/ Akt pathway to regulate proliferation, and use genetic screens to identify additional components of the pathway. Third, we will test the hypothesis that the chalone blocks the cell cycle by inhibitin the activity of the G2/ M regulators Cyclin B and Cdc2. Together, this work combining natural products chemistry, physics and mathematical modeling, genetics, cell biology, and biochemistry in a versatile model system wil elucidate the molecular mechanism of a chalone.

描述（由申请人提供）：发育生物学中的一个基本但鲜为人知的问题是，当组织或整个身体中该细胞类型的细胞密度达到正确点时，细胞如何停止增殖。理论上，实现这一目标的一种方法是细胞分泌一种抑制该细胞类型增殖的特定扩散因子。这种称为查酮的因子的细胞外浓度会随着分泌细胞密度的增加而增加，并且当该细胞类型的密度达到正确的值时点，相应高水平的查酮就会阻止它们的扩散。尽管有证据表明查酮的存在，但人们对查酮的身份及其信号转导途径知之甚少。在简单的真核模型系统盘基网柄菌中，即使存在足够的营养，细胞在达到高细胞密度时也会停止增殖。这是由于查酮在细胞外的积累所致。我们对查龙进行了部分纯化，发现它是一种耐热、耐蛋白酶的阴离子分子，小于2 kDa。查龙信号转导途径涉及 PTEN 和 CnrN 磷酸酶以及 BzpN 转录因子，并通过阻止从 G2 到 G2 的转变来阻断增殖。细胞周期的M期。我提出了三个具体目标，即利用盘基网柄菌模型系统的力量来阐明这种查酮及其信号转导途径。首先，我们将完成查龙酮的纯化和鉴定，并测试查龙酮函数的理论模型。其次，我们将测试查龙酮调节 PI3 激酶/Akt 通路以调节增殖的假设，并使用遗传筛选来鉴定该通路的其他成分。第三，我们将检验查龙酮通过抑制 G2/M 调节因子 Cyclin B 和 Cdc2 的活性来阻断细胞周期的假设。这项工作将天然产物化学、物理和数学建模、遗传学、细胞生物学和生物化学结合在一个多功能模型系统中，将阐明查酮的分子机制。