2006-11-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/698307摘要：組蛋白(Histone)修飾能夠調節核染色質(chromatin)的結構及基因的表現。組蛋白去乙醯酵素(Histone deacetylaes, HDACs)能夠將組蛋白上的乙醯基移除並抑制轉錄。在動物系統中，HDACs在調節基因表現、細胞分化及發育的重要性已經有深入研究。相較之下，有關HDACs在植物的功能及作用機制的知識甚少，並且沒有任何關於HDACs下游目標基因的訊息。真核細胞的HDACs可藉由於酵母 HDACs的同源性劃分成三個家族：RPD3、HDA1和SIR2。阿拉伯芥基因組包含了四種RPD3類型的HDACs，分別為：HDA6、HDA7、HDA9及HDA19。我們最近的研究發現HDA6的突變會造成阿拉伯芥開花的遲滯。在HDA6的突變體中，FLC的表現被高度調節和高度乙醯化。FLC是能夠阻止植物從營養生長過渡到生殖生長的轉錄因子。這一結果表明HDA6能夠通過抑制FLC來調節開花。本研究將揭示RPD3類型的HDACs在植物開花中的作用，鑑定與HDA6交互作用的蛋白質以及組蛋白乙醯化調節的下游目標基因，並且闡明組蛋白乙醯化調節基因表現的機制。這些研究將會對於植物染色質相關的基因調節有更深入的了解。由於組蛋白乙醯化對於基因表現的重要性，深入了解HDACs如何調節基因表現將更加進一步的揭示植物生長發育與如何適應環境的分子機理。<br> Abstract: Histone modifications regulate the accessibility of chromatin and gene activity. Histone deacetylases (HDACs) are enzymes that remove acetyl groups from core histones and facilitating the transcription repression. The importance of HDACs in the regulation of gene expression, cell differentiation, and development has been established in animal systems. In contrast, much less is known concerning the function and mechanism of action of HDACs in plants. No information is available regarding the physiological roles and downstream target genes of HDACs in plants. Eukaryotic HDACs can be grouped into three major families based on their primary homology to the yeast HDACs, RPD3, HDA1 and SIR2. Arabidopsis genome contains four RPD3-type HDACs, namely, HDA6, HDA7, HDA9 and HDA19. Our recent studies indicate that mutations of HDA6 resulted in delayed flowering in Arabidopsis. The expression of FLC, a transcription factor that blocks the transition from vegetative to reproductive development, was upregulated and hyperacetylated in the HDA6 mutant, axe1-5, and HDA6 RNA-interfering plants, suggesting that HDA6 is involved in flowering by repressing FLC expression. The proposed research will elucidate the role of RPD3-type HDACs in flowering. The interacting proteins of HDA6 and the downstream targets regulated by histone acetylation will be identified. The mechanisms mediating gene regulation by histone acetylation will be illustrated. This study will provide insights into chromatin-associated gene regulation in plants. Given the importance of histone acetylation in the regulation of gene expression in plants, a better understanding of how HDACs modulate gene expression may have wide application in crop improvement. Results from this project may lead to a more comprehensive study of how plants response to environmental cues during plant growth and development.去乙醯基酵素HDA6開花ChIP-on-chiphistone deacetylasesHDA6floweringChIP-on-chip