Understanding Mechanisms Underlying Drosophila Neurofibromatosis-1 Defects

了解果蝇神经纤维瘤病 1 缺陷的潜在机制

• 批准号: 7686701
• 负责人: ANDRE BERNARDS
• 金额: $ 35.38万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7686701
• 关键词: Adenylate Cyclase; Adult; Advocate; Affect; Affinity Chromatography; Animal Model; Attenuated; Behavior; Benign; Biochemical; Biochemical Genetics; Biological; Cell physiology; Cells; Chromosomes; Code; Computer Analysis; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data Set; Defect; Dominant-Negative Mutation; Drosophila genus; Drosophila melanogaster; Embryo; GTPase-Activating Proteins; Gene Expression; Genes; Genetic; Genetic Models; Genetic Screening; Goals; Growth; Hereditary Disease; Hormonal; Hormone Receptor; Hormones; Human; Incidence; Larva; Learning; Ligands; Malignant Neoplasms; Mass Spectrum Analysis; Modeling; Molecular; Mutation; NF1 gene; Neuroendocrine Cell; Neurofibromatoses; Neurofibromatosis 1; Neurofibromatosis Type 1 Protein; Neurons; Neuropeptide Receptor; Neurosecretory Systems; Pathway interactions; Patients; Phenotype; Production; Protein Isoforms; Protein Tyrosine Kinase; Proteins; Publishing; RNA Interference; Regulation; Reporting; Research; Resolution; Role; Secondary to; Severity of illness; Signal Transduction; Symptoms; Testing; Tissues; Transgenes; Validation; Work; X Chromosome; fly; follow-up; human disease; in vivo; man; mutant; public health relevance; ras GTPase-Activating Proteins; research study; tumor

DESCRIPTION (provided by applicant): Neurofibromatosis type 1 (NF1) is a highly variable and unpredictable disease, the severity of which appears to be determined by as yet unknown modifier genes. The NF1 gene encodes neurofibromin, whose only agreed upon function is to serve as a negative regulator of Ras. Beyond benign and malignant tumors, NF1 patients also suffer from several less well understood non-tumor symptoms, including an overall growth deficiency and learning problems. A Drosophila NF1 model displays phenotypes resembling these non-tumor symptoms. Strikingly, most Drosophila NF1 phenotypes are not readily modified by attenuating Ras signaling, but are restored by increasing signaling through the cAMP-dependent protein kinase A (PKA) pathway. This has made determining how NF1 affects cAMP signaling a central issue in NF1 research. Our results indicate that the overall growth defect of Drosophila NF1 mutants reflects a non-cell-autonomous requirement for RasGAP activity in specific larval neurons. We initially suggested that this primary Ras signaling defect in turn causes a secondary hormonal defect, which is mitigated by increasing cAMP. New evidence now suggests an alternative dual-function hypothesis, which states that NF1 is not just required in neuroendocrine cells to regulate Ras and the production of one or more hormones, but also in hormone responding cells to efficiently couple hormone receptors to adenylyl cyclase. We propose a combination of genetic and biochemical approaches to test the merits of this hypothesis, which may explain why we and others have reached contradictory conclusions about NF1 functions essential for phenotypic rescue. Our new results have implicated the neuroendocrine Ret tyrosine kinase, and an adenylyl cyclase-coupled neuropeptide receptor and its ligand as genetic suppressors of the NF1 size defect. We propose four interconnected sets of genetic and biochemical experiments to follow up on these results, and to achieve our overall goal of providing a molecular description of mechanisms underlying NF1 defects. PUBLIC HEALTH RELEVANCE Neurofibromatosis type 1 (NF1) is among the most common genetic diseases of man. Its estimated incidence of 1 in 3,000 suggests there may be 100,000 NF1 patients in the US alone. In this project we will use a combination of biochemical, molecular biological, and genetic approaches in the genetic model organism, Drosophila melanogaster, to identify mechanisms responsible for NF1 defects A better understanding of these mechanisms is a required step on the road to rational therapy for NF1.

描述（由申请人提供）：1型神经纤维瘤病（NF1）是一种高度可变且不可预测的疾病，其严重程度似乎取决于尚不清楚的修饰基因基因。 NF1基因编码神经纤维蛋白，其唯一同意的功能是作为RA的负调节剂。除了良性和恶性肿瘤外，NF1患者还患有几种不太了解的非肿瘤症状，包括总体生长缺乏症和学习问题。果蝇NF1模型显示出类似这些非肿瘤症状的表型。引人注目的是，大多数果蝇NF1表型不会通过减弱RAS信号传导而容易修饰，而是通过通过CAMP依赖性蛋白激酶A（PKA）途径增加信号来恢复。这已经确定了NF1如何影响cAMP信号在NF1研究中的一个核心问题。我们的结果表明，果蝇NF1突变体的总体生长缺陷反映了特定幼虫神经元中RasGAP活性的非细胞自治需求。我们最初建议这种主要的RAS信号传导缺陷反过来导致次级激素缺陷，从而通过增加cAMP来缓解这种缺陷。现在的新证据表明，另一种双重功能假设，该假设指出，NF1不仅需要在神经内分泌细胞中调节RAS和一种或多种激素的产生，而且还需要在激素反应细胞中以有效将激素受体与腺苷酸环酶进行添加。我们提出了遗传和生化方法的结合来检验该假设的优点，这可以解释为什么我们和其他人就表型救援必不可少的NF1功能得出了矛盾的结论。我们的新结果暗示了神经内分泌RET酪氨酸激酶和腺苷酸环偶联剂受体及其配体作为NF1大小缺陷的遗传抑制子。我们提出了四个相互联系的遗传和生化实验，以跟进这些结果，并实现我们提供NF1缺陷基础机制的分子描述的总体目标。公共卫生相关性神经纤维瘤病1型（NF1）是人类最常见的遗传疾病之一。它的估计发生率为3,000分之一，这表明仅在美国就可能有100,000名NF1患者。在该项目中，我们将使用遗传模型有机体中的生化，分子生物学和遗传方法的结合，果蝇果蝇（Drosophila Melanogaster）来识别负责NF1缺陷的机制，这是对这些机制的更好理解，这是NF1合理治疗道路的必需步骤。