Mechanisms of gene regulation by the plant MADS-domain transcription factor AGL15 and developmental outcomes.

AGL15是一种参与植物胚胎发育的转录因子。转录因子是通过结合DNA和打开或关闭基因来发挥作用的蛋白质。AGL15是一个“双峰”因子的例子，它直接表达一些基因，但直接抑制其他基因，这个项目的重点是了解这是如何发生的。由于双重功能的机制在任何生物中都没有得到很好的理解，因此拟议的工作将对理解这些类型的因素具有更广泛的相关性。此外，AGL15参与种子发育，种子对人类至关重要，我们的大部分饮食直接来自种子。此外，这项工作将有助于理解体细胞胚胎发生，这是允许植物基因工程以应对农业挑战的一个步骤。将为一名博士后学者、一名研究生和本科生研究人员提供培训，包括接待附近社区大学的实习生。该项目将支持一些持续的外展活动，以及与一所小学建立新的关系，该小学的学生来自经济困难的家庭。AGL15是一种拟南芥MADS因子，参与发育阶段的转换，直接表达一些基因，但直接抑制其他基因。抑制的机制可以通过AGL15与组蛋白脱乙酰酶复合物（HDAC）的一部分SAP 18/TPL的相互作用来解释。这种相互作用需要在AGL15的C-末端结构域内发现的LxLxL/LxL基序。鉴定这些相互作用的酵母双杂交筛选也分离出了可以解释AGL15如何募集到基因调控元件导致直接靶点表达的蛋白质。这些有趣的蛋白质，其中包括另一个MADS因子，SEP 3，与染色质重塑成分和植物特异性转录因子（LBD 40）相互作用，将进一步研究，HDAC相互作用，并在植物中与AGL 15相互作用测试。将评估募集HDAC复合物所需的LxLxL基序在发育中的功能重要性。先前的NSF支持使PI的实验室能够绘制AGL 15与DNA位点和靶基因反应的全基因组关联。类似地确定AGL 15相互作用蛋白的体内缔合将允许确定共占据，这可能揭示调节结果的机制。一些互作将评估如何占用从胚胎到幼苗的变化。先前关于AGL15的工作提供了关于具有不同调节结果的不同复合物如何被募集到特定位点的线索。虽然映射协会将有助于确定机制，实验也提出了直接解决的假设，激活可能涉及多个结合位点的AGL15和循环，而镇压没有。最后，将进一步评估选定的靶点在发育中的表观遗传调控和功能。各级科学培训是该项目的一个组成部分。

AGL15 is a transcription factor involved in plant embryo development. Transcription factors are proteins that function by binding DNA and turning genes on or off. AGL15 is an example of a 'bimodal' factor that directly expresses some genes, but directly represses other genes, and the focus of this project is to understand how this occurs. Because mechanisms of dual functionality are not well understood in any organism, the proposed work will have broader relevance to understanding these types of factors. Furthermore, AGL15 is involved in seed development, and seeds are of critical importance to humans, with the majority of our diets directly derived from seeds. Additionally, work will contribute to understanding somatic embryogenesis, a step allowing genetic engineering of plants to meet agricultural challenges. Training will be provided for a postdoctoral scholar, a graduate student, and undergraduate researchers, including hosting interns from the nearby community college. This project will support a number of continuing outreach activities as well as developing a new relationship with an elementary school with a high percentage of students from economically disadvantaged homes.AGL15 is an Arabidopsis MADS-factor involved in developmental phase transitions that directly expresses some genes, but directly represses others. The mechanism of repression may be explained by AGL15's interaction with SAP18/TPL that is part of a histone deacetylase complex (HDAC). This interaction requires an LxLxL/EAR motif that is found within the C-terminal domain of AGL15. The yeast 2-hybrid screen that identified these interactions also isolated proteins that could account for how AGL15 recruitment to gene regulatory elements leads to expression of direct targets. These intriguing proteins, which include another MADS-factor, SEP3, that interacts with chromatin remodeling components and a plant-specific transcription factor (LBD40), will be further investigated, as will the HDAC interaction, and in planta interaction with AGL15 tested. The LxLxL motif, needed for recruitment of the HDAC complex, will be assessed for functional importance in development. Prior NSF support has allowed the PI's lab to map genome wide association of AGL15 with DNA sites and response of target genes. Similar determination of the in vivo association of AGL15 interacting proteins will allow co-occupancy to be determined that may be revealing for mechanism of regulatory outcomes. Some interactors will be assessed for how occupancy changes from embryo to seedling. Prior work on AGL15 has provided clues as to how different complexes with different regulatory outcomes are recruited to specific loci. While mapping association will aid in determining mechanism, experiments are also proposed to directly address the hypothesis that activation may involve multiple binding sites for AGL15 and looping, whereas repression does not. Finally, select targets will be further assessed for epigenetic regulation and function in development. Training at all levels of science are an integral part of the project.