Proopiomelanocortin gene expression and obesity

阿黑皮质素原基因表达与肥胖

• 批准号: 7069676
• 负责人: MALCOLM James LOW
• 金额: $ 27.62万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7069676
• 关键词: biological signal transduction; cell surface receptors; diabetes mellitus; diabetes risk; gene expression; genetic transcription; genetically modified animals; hypothalamus; laboratory mouse; laser capture microdissection; leptin; metabolic syndrome; obesity; proopiomelanocortin; transcription factor

DESCRIPTION (provided by applicant): Obesity and associated metabolic disorders including diabetes have become epidemic worldwide and threaten the health of millions. A recent confluence of data from human population genetics studies, mouse transgenic experiments, and neuropeptide pharmacology has implicated the proopiomelanocortin (POMC) gene, its encoded peptides, and their cognate G-protein coupled receptors as essential components of the neural circuits that regulate food intake and energy expenditure. Evolution has resulted in functionally and topographically distinct DNA regulatory elements that control POMC transcription in either neurons or pituitary endocrine cells, and which are highly conserved across mammalian species. These distinctions in cell-type specific POMC promoter and enhancer elements are mirrored by unique complements of transcription factors that differentially regulate POMC gene expression in the brain versus pituitary gland. POMC expression in hypothalamic neurons is quantitatively associated with adipose mass over the lifetime of a mouse and we hypothesize that in humans the analogous control of neuronal POMC gene expression is a key regulatory switch determining the ultimate balance of fat storage or utilization. The first aim of this project is to further characterize the neuronal-specific enhancer elements of the POMC gene using a combination of in vivo transgenic and in vitro primary neuronal culture expression systems, guided by additional cross-species comparative sequencing. A second aim will specifically determine the interaction of POMC gene regulatory elements with components of the leptin receptor-signaling pathway to result in activation of neuronal POMC gene transcription by the adipocyte-derived hormone. Third, the quantitative and qualitative effects of selective neural enhancer mutations in the context of the endogenous mouse POMC gene will be rigorously tested by genetic knock-in strategies. Fourth, the mRNA "transcriptome" of POMC neurons isolated by lasercapture microscopy will be defined, and the cognate DNA-binding transcription factors responsible for neuron-specific POMC gene expression will be identified and cloned using both computational genomics and screening of yeast one-hybrid cDNA libraries constructed from amplified POMC neuron-specific RNA. Throughout these studies we will collaborate with our clinical colleagues, who are involved in human genome-wide screens and index case-based gene sequencing projects, in a translational effort to identify and functionally characterize additional polymorphic alleles of either the POMC gene itself or candidate neuronal POMC gene transcription factors underlying altered weight regulation.

描述（由申请人提供）：包括糖尿病在内的肥胖和相关代谢疾病已在全球流行，并威胁着数百万的健康。人群遗传学研究，小鼠转基因实验和神经肽药理学的数据最近汇合的融合暗示了proopiomelananocortin（POMC）基因，其编码的肽以及其同源G蛋白偶联受体是调节食物摄入量的神经环形的必不可少的成分。进化导致功能和地形上不同的DNA调节元件控制神经元或垂体内分泌细胞中的POMC转录，并且在哺乳动物物种中高度保守。细胞类型的特异性POMC启动子和增强子元件中的这些区别反映了转录因子的独特补充，这些互补因素差异地调节了大脑与垂体中的POMC基因表达。下丘脑神经元中的POMC表达与小鼠一生中的脂肪质量相关，我们假设在人类中，神经元POMC基因表达的类似控制是确定脂肪储存或利用的最终平衡的关键调节开关。该项目的第一个目的是进一步表征POMC基因的神经元特异性增强子元素，使用体内转基因和体外原发性神经元培养表达系统的组合，并以其他跨体性比较测序为指导。第二个目标将特异性确定POMC基因调节元件与瘦素受体信号途径的成分的相互作用，从而导致通过脂肪细胞衍生的激素激活神经元POMC基因转录。第三，在内源性小鼠POMC基因的背景下，选择性神经增强子突变的定量和定性作用将通过遗传敲击策略进行严格测试。 Fourth, the mRNA "transcriptome" of POMC neurons isolated by lasercapture microscopy will be defined, and the cognate DNA-binding transcription factors responsible for neuron-specific POMC gene expression will be identified and cloned using both computational genomics and screening of yeast one-hybrid cDNA libraries constructed from amplified POMC neuron-specific RNA.在这些研究中，我们将与我们的临床同事合作，他们参与人类全基因组筛查和基于索引的基因测序项目，以转化努力，以识别并在功能上表征POMC基因本身或候选神经元POMC基因转录因子的其他多态性等位基因的其他多态性等位基因。