Specific Repression of Prolactin Gene Expression

催乳素基因表达的特异性抑制

基本信息

批准号：
8230671
负责人：
RICHARD N DAY
金额：
$ 28.98万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-07-11 至 2015-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8230671
关键词：
Address Affect Anterior Pituitary Gland Anterior Pituitary Hormones Architecture Behavioral Binding Proteins Biochemical Biological Models Biomedical Research Bone Development CCAAT-Enhancer-Binding Protein-alpha Cell Nucleus Cell model Cells Chromatin Complex DNA Binding Development Disease Dopamine Embryonic Development Enhancers Environment Failure Female Fertility Gene Expression Gene Expression Regulation Gene Targeting Genes Genetic Transcription Genome Health Heterochromatin Homeodomain Proteins Human Hyperprolactinemia Hypothalamic structure Knockout Mice Lactotrope Cell Lead Life Link Lysine Macromolecular Complexes Mammary gland Maps Metabolism Methylation Molecular Multiprotein Complexes Mus Mutation Neurons Neurosecretory Systems Nuclear Phenotype Physiological Pituitary Gland Play Primary Neoplasm Process Prolactin Prolactin Receptor Prolactinoma Proteins Recruitment Activity Regulation Regulator Genes Repression Retinoblastoma Role Somatotrope Cell Testing Therapeutic Transgenic Mice Woman Work cell type cellular imaging chromatin remodeling design disease-causing mutation genetic regulatory protein histone methyltransferase homeodomain human disease male men mouse model promoter protein complex protein function reproductive transcription factor transcription factor Pit-1

项目摘要

DESCRIPTION (provided by applicant): A major challenge facing biomedical research is to determine how the network of interactions involving gene regulatory proteins is controlled in the context of the natural environment inside living cells, and to understand how disease processes affect these activities. The expression of the prolactin (PRL) gene in anterior pituitary lactotrope cells is a proven model system to define the molecular mechanisms that contribute to the control of cell type-specific gene regulation. In the pituitary cell nucleus, the homeodomain (HD) transcription factor Pit-1 orchestrates the activities of a network of regulatory proteins that control PRL gene expression. The broad objective of this proposal is to use emerging concepts in nuclear architecture and chromatin remodeling to determine how Pit-1 coordinates the activities of multi-protein complexes at specific gene enhancers and promoters. Pit-1 regulates PRL transcription through its interactions with other coregulatory proteins including the CCAAT/enhancer-binding protein alpha (C/EBP1). C/EBP1 in turn associates with the heterochromatin binding protein 1 alpha (HP11) in regions of centromeric heterochromatin, and Pit-1 can recruit C/EBP1 from the regions of compact chromatin. Disease-causing mutations in Pit-1 disrupt this network of protein interactions, and these results have broad implications for many human diseases linked to mutations in the HD proteins. The studies in this proposal use the combination of biochemical analysis and live-cell imaging to test the hypothesis that Pit-1 interactions with the C/EBP1-HP11 complex function to remodel densely packaged chromatin, allowing the access of pituitary-specific transcription factors to target genes. The first aim is to define the interactions of C/EBP1 and HP11 in regions of heterochromatin in pituitary cells, and then to determine the role of Pit-1 in regulating this network of protein interactions. The second aim is to determine how these interactions function to control local chromatin remodeling. The third aim will take advantage of newly developed transgenic mouse models that allow the unambiguous identification of living lactotrope or somatotropes cells to map the network of Pit-1 interactions in the normal mature mouse pituitary cells. Relevance: The anterior pituitary hormone PRL has many diverse physiological roles, and the failure to regulate PRL synthesis leads to reproductive disturbances in both men and women, and can lead to prolactinomas, the most common intracranial primary tumor. If we are to understand disease processes and design therapeutic strategies, it is important to define how specific gene regulatory complexes are assembled in the intact cell nucleus. Discovering how nuclear architecture controls gene expression will be the cornerstone for understanding how genomes work.

描述（由申请人提供）：生物医学研究面临的一个重大挑战是确定如何在活细胞内部自然环境的背景下控制涉及基因调节蛋白的相互作用网络，并了解疾病过程如何影响这些活动。垂体前乳糖细胞中催乳素（PRL）基因的表达是一种验证的模型系统，旨在定义有助于控制细胞类型特异性基因调节的分子机制。在垂体细胞核中，同源域（HD）转录因子pit-1策划了控制PRL基因表达的调节蛋白网络的活性。该提案的广泛目的是在核结构和染色质重塑中使用新兴概念来确定PIT-1如何在特定基因增强子和启动子上坐标多蛋白质复合物的活性。 PIT-1通过与其他核调节蛋白（包括CCAAT/增强子结合蛋白α（C/EBP1））的相互作用来调节PRL转录。 C/EBP1依次与丝粒异染色质区域中的异染色质结合蛋白1α（HP11）相关联，而PIT-1可以从紧凑型染色质区域募集C/EBP1。 PIT-1中引起疾病的突变破坏了这种蛋白质相互作用网络，这些结果对与HD蛋白突变有关的许多人类疾病具有广泛的影响。该提案中的研究使用生物化学分析和活细胞成像的组合来检验以下假设：PIT-1与C/EBP1-HP11复合函数相互作用以重塑密集包装的染色质，从而允许垂体特异性转录因子访问靶基因。第一个目的是定义垂体细胞中异染色质区域中C/EBP1和HP11的相互作用，然后确定PIT-1在调节这种蛋白质相互作用网络中的作用。第二个目的是确定这些相互作用如何控制局部染色质重塑。第三个目标将利用新开发的转基因小鼠模型，该模型允许对活乳糖或体体细胞的明确鉴定来绘制正常成熟小鼠垂体细胞中PIT-1相互作用的网络。相关性：垂体前激素PRL具有多种生理作用，并且未能调节PRL合成的未调节会导致男性和女性的生殖障碍，并且可能导致催乳素瘤，这是最常见的颅内原发性肿瘤。如果我们要了解疾病过程和设计治疗策略，那么重要的是要定义如何在完整的细胞核中组装特定的基因调节络合物。发现核结构如何控制基因表达将是理解基因组如何工作的基石。