Molecular Mechanisms of Genomic Reprogramming during Germ Cell Specification

生殖细胞规范过程中基因组重编程的分子机制

• 批准号: 8097319
• 负责人: Sujata Bhattacharyya
• 金额: $ 5.87万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8097319
• 关键词: Acetylation; Address; Affect; Animals; Antineoplastic Agents; Biochemical; Biological Assay; Biological Models; Birth; Caenorhabditis elegans; Cancerous; Cells; Charge; Chromatin; Chromatin Structure; Coupled; DNA-Directed RNA Polymerase; Data; Drosophila genus; Embryo; Environment; Epigenetic Process; Event; Excision; Gene Silencing; Genetic; Genetic Transcription; Genome; Genomics; Germ Cells; Germ Lines; Goals; Histone Acetylation; Histone Deacetylase; Histone Deacetylase Inhibitor; Histone Deacetylation; Histone H3; Histone H4; Histones; Invertebrates; Knowledge; Light; Link; Lysine; Maintenance; Mammals; Modeling; Molecular; Mus; Nature; Newborn Infant; Organism; Parkinson Disease; Pathway interactions; Phosphorylation; Polymerase; Post-Translational Protein Processing; Process; Property; Proteins; RNA Interference; RNA Polymerase II; Regulation; Regulator Genes; Repression; Role; Signal Transduction; Specificity; Stem cells; Structure of primordial sex cell; Time; Tissues; Transferase; Transgenic Organisms; Variant; Vertebrates; Zinc Fingers; blastomere structure; cell type; chromatin remodeling; embryo stage 2; gene repression; genome-wide; loss of function; mature animal; mutant; next generation; prevent; progenitor; public health relevance; research study; tumorigenic

DESCRIPTION (provided by applicant): Germ cells are remarkable in that, of all the cell types found in an organism they alone retain the ability to give rise to all the embryonic and extra-embryonic cell types that contribute to an organism. This property of totipotency is protected in primordial germ cells (PGCs) by their maintenance of a transcriptionally repressed genome. Two temporally and biochemically distinct mechanisms accomplish this objective in C. elegans. Initially, a C.elegans-specific maternal protein PIE-1, specifically partitioned to the germ line blastomeres, inhibits activation of RNA polymerase. Shortly, after the birth of the PGCs, PIE-1 is degraded and dramatic genome-wide chromatin remodeling occurs to sustain transcriptional repression. However, pathways involved in regulating effectors of global remodeling of the genome remain unknown. A significant goal of this proposal is to uncover molecular mechanisms underlying the specific loss of various marks of 'active' chromatin in newly bom germ cells. The role of RNA polymerase, histone variants and post-translational modifications will be interrogated in the control of these erasure events. Initial experiments also suggest specific activation of histone deacetylase (HDAC) activity at the birth of the primordial germ cells, Z2 and Z3. In complementary approaches, using loss-of-function mutants, RNA interference and transgenic misexpression, the consequence of persistent histone acetylation on the germ-line will be elucidated. Finally, translational and post-translational control of HDAC activity will be probed using genetic and biochemical approaches. Public Health Relevance: These studies address a fundamental question of biomedical relevance: how do embryonic cells, and for that matter, stem cells retain the ability to differentiate into all lineages of the adult animal? The answer to this question will undoubtedly have enormous ramifications for manipulating cells to generate tissue-specific progenitors that could ultimately be used to cure debilitating, degenerative illnesses such as Parkinson's. Additionally, since histone deacetylation has been implicated in aberrant gene silencing in cancerous cells and HDAC inhibitors are being developed as effective anti-cancer drugs, our long-term goal is to utilize our knowledge of histone deacetylation regulation to increase the specificity of next generation epigenetic therapies.

描述（由申请人提供）：生殖细胞的显着之处在于，在生物体中发现的所有细胞类型中，它们单独保留了产生对生物体有贡献的所有胚胎和胚胎外细胞类型的能力。原始生殖细胞（PGC）通过维持转录抑制基因组来保护这种全能性。在秀丽隐杆线虫中，两种时间上和生化上不同的机制实现了这一目标。最初，线虫特异性母体蛋白 PIE-1，专门分配到种系卵裂球，抑制 RNA 聚合酶的激活。 PGC 诞生后不久，PIE-1 被降解，并且发生剧烈的全基因组染色质重塑以维持转录抑制。然而，参与调节基因组整体重塑效应子的途径仍然未知。该提案的一个重要目标是揭示新生生殖细胞中“活性”染色质各种标记的特定丢失的分子机制。 RNA 聚合酶、组蛋白变体和翻译后修饰的作用将在这些擦除事件的控制中受到质疑。初步实验还表明，组蛋白脱乙酰酶 (HDAC) 活性在原始生殖细胞 Z2 和 Z3 诞生时被特异性激活。在补充方法中，使用功能缺失突变体、RNA 干扰和转基因错误表达，将阐明种系上持续组蛋白乙酰化的后果。最后，将使用遗传和生化方法探讨 HDAC 活性的翻译和翻译后控制。 公共健康相关性：这些研究解决了生物医学相关性的一个基本问题：胚胎细胞以及干细胞如何保留分化成成年动物所有谱系的能力？这个问题的答案无疑将对操纵细胞产生组织特异性祖细胞产生巨大影响，这些祖细胞最终可用于治疗帕金森氏症等衰弱的退行性疾病。此外，由于组蛋白脱乙酰化与癌细胞中的异常基因沉默有关，并且 HDAC 抑制剂正在开发为有效的抗癌药物，因此我们的长期目标是利用我们对组蛋白脱乙酰化调节的知识来提高下一代表观遗传疗法的特异性。