Mechanisms of Transcriptional Repression in Arabidopsis

拟南芥转录抑制机制

• 批准号: 8010184
• 负责人: JEFFREY A LONG
• 金额: $ 41.49万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-27 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8010184
• 关键词: Acetylation; Affect; Alleles; Animals; Arabidopsis; Biological; Cells; Complex; Data; Development; Developmental Biology; Disease; Embryo; Embryonic Development; Embryonic Lethal Mutation; Enhancers; Flowers; Funding; Gene Targeting; Genes; Genetic Screening; Genetic Transcription; Histone Acetylation; Histone Deacetylase; Human; Human Pathology; Institutes; Knowledge; Lead; Link; Logic; Malignant Neoplasms; Molecular Genetics; Mouse-ear Cress; Mutation; Organ; Organism; Pathway interactions; Pattern; Phenotype; Plant Roots; Plants; Play; Process; Production; Proteins; Public Health; Regulatory Element; Regulatory Pathway; Relative (related person); Role; Sorting - Cell Movement; Specific qualifier value; Staging; System; Technology; Time; To specify; Transcription Repressor/Corepressor; Work; cancer type; cell type; chromatin immunoprecipitation; cis acting element; design; gain of function; gene repression; genome-wide; genome-wide analysis; loss of function; mutant; promoter; public health relevance; research study; tool

DESCRIPTION (provided by applicant): In both plants and animals, a large number of unique cell types must be specified during development. It has become increasingly clear that as cells differentiate, not only must genes be transcriptionally activated, but the transcription of others must be repressed. In animals, mutations in genes that regulate transcriptional repression can lead to many types of cancer or result in embryonic lethality. Therefore it is important to identify and understand the mechanisms by which these proteins act. We have identified two proteins in Arabidopsis, TOPLESS (TPL) and HISTONE DEACETYLASE 19 (HDA19), that work in concert to repress transcription during embryogenesis and flower development. TPL encodes a transcriptional corepressor that forms a complex with HDA19 to maintain cell fates during development. Unlike in animal systems where mutations in similar proteins are embryonic lethal, mutations in both TPL and HDA19 are completely viable in Arabidopsis, allowing us to study their roles at multiple developmental stages. In AIM1, we will perform chromatin immunoprecipitations followed by massively parallel sequencing (ChIP seq) to identify the common direct targets of TPL and HDA19 during embryogenesis. We will then employ mis-expression and loss-of-function analysis to determine the function of these downstream targets. In AIM2, we will perform ChIP seq on TPL and HDA19 during floral development to elucidate their downstream targets at a second stage of development. We will then analyze the extent of histone acetylation on a subset of target promoters over time, as well as perform expression, mis-expression and loss-of-function studies. In AIM3 we will perform genetic screens on hda19 mutants to identify other proteins in the TPL/HDA19 pathway. These experiments will allow us to explore one of the mechanisms that plants use to specify and maintain cell types during development. It will allow us to compare the proteins and logic used in plants to those used in similar processes in animal development, leading to a better understanding of both. PUBLIC HEALTH RELEVANCE: Understanding how different cell types are specified in an organism is fundamental to public health as this process is critical for development, and disruption of it leads to various diseases in humans. This proposal aims to explore one aspect of this process, transcriptional repression, which has been linked to several human pathologies such as cancer. The findings from this study will aid in our understanding of the mechanisms that govern this important process.

描述（由申请人提供）：在植物和动物中，在发育过程中必须指定大量独特的细胞类型。越来越清楚的是，随着细胞分化，不仅基因必须被转录激活，而且其他基因的转录也必须被抑制。在动物中，调节转录抑制的基因突变可能导致多种类型的癌症或导致胚胎死亡。因此，识别和理解这些蛋白质的作用机制非常重要。我们在拟南芥中鉴定出了两种蛋白质：TOPLESS (TPL) 和组蛋白脱乙酰酶 19 (HDA19)，它们在胚胎发生和花发育过程中协同抑制转录。 TPL 编码转录辅阻遏物，与 HDA19 形成复合物以维持发育过程中的细胞命运。与动物系统中类似蛋白质的突变导致胚胎致死不同，TPL 和 HDA19 的突变在拟南芥中完全可行，使我们能够研究它们在多个发育阶段的作用。在 AIM1 中，我们将进行染色质免疫沉淀，然后进行大规模并行测序 (ChIP seq)，以识别胚胎发生过程中 TPL 和 HDA19 的共同直接靶标。然后，我们将采用错误表达和功能丧失分析来确定这些下游目标的功能。在 AIM2 中，我们将在花发育过程中对 TPL 和 HDA19 进行 ChIP seq，以阐明它们在发育第二阶段的下游目标。然后，我们将分析一段时间内目标启动子子集上组蛋白乙酰化的程度，并进行表达、错误表达和功能丧失研究。在 AIM3 中，我们将对 hda19 突变体进行遗传筛选，以鉴定 TPL/HDA19 途径中的其他蛋白质。这些实验将使我们能够探索植物在发育过程中用来指定和维持细胞类型的机制之一。它将使我们能够将植物中使用的蛋白质和逻辑与动物发育中类似过程中使用的蛋白质和逻辑进行比较，从而更好地理解两者。 公共健康相关性：了解生物体中不同细胞类型的特定方式对于公共健康至关重要，因为这一过程对于发育至关重要，而其破坏会导致人类各种疾病。该提案旨在探索这一过程的一个方面，即转录抑制，它与癌症等多种人类病理有关。这项研究的结果将有助于我们理解控制这一重要过程的机制。