Context-dependent activity of an essential transcription factor

多细胞生物通过精心控制的发育过程获得其复杂的形状。植物发育的关键调节因子包括一类被称为转录因子的蛋白质，它们协调植物细胞和组织的特异性和功能。一些转录因子的作用仅限于少数细胞或一小部分组织，但还有其他因子在大量发育中的组织中发挥关键作用。这引发了一个有趣的生物学问题：相同的转录因子如何产生不同的发育结果？这个项目通过确定相同的转录因子如何在不同的细胞和组织中发挥不同的功能来回答这个问题。该项目结合了遗传学和生物化学技术，包括在蛋白质-蛋白质相互作用的高分辨率图谱方面的进展。这项提议的核心是将传统上被排除在研究密集型机构之外的学生包括在内。在俄亥俄州立大学(OSU)，这表现在黑人学生和有色人种学生在俄亥俄州立大学的地区校园中比例过高，那里的研究机会有限。为了缓解这一问题，本科生将被带到俄亥俄州立大学哥伦布主校区，提供食宿，支付津贴，并加入一个由100名学生组成的联盟，整合各种同时进行的暑期研究项目。这条管道通过消除在暑期打工和探索研究作为职业之间的不公平选择，扩大了传统上被排除在外的群体的参与。生物发展是由转录因子(TF)活性驱动的严格控制的基因表达产生的。在整个进化过程中，转录因子被反复地用于调节关键的发育进展，部分原因是它们的产出根据发育背景而变化。产生这些上下文相关读数的机制在很大程度上仍不清楚，这种知识差距在植物界尤其大。这一差距将使用III类同源结构域-亮氨酸拉链(HD-ZIPIII)TF作为模型来解决。HD-ZIPIII蛋白是一个特别吸引人的模型，因为它们调控着广泛的基本发育过程，作用于从分生组织到根到侧生器官的各种组织和器官。此外，HD-ZIPIII蛋白结构包括一个与STAR相关的脂转移(START)结构域。起始结构域通常由亲脂配体激活，并经常介导蛋白质-蛋白质相互作用，提供了产生上下文相关活性的可能机制。这项提议将在两种功能不同的细胞类型中测试具有代表性的HD-ZIPIII PHABULOSA(PHB)的遗传后果和功能伙伴关系：地上部顶端分生组织的不确定细胞和叶片近轴侧的确定细胞。包括全球基因组图谱和邻近标记在内的实验将识别特定于分生组织和叶片的PHB基因调控网络和相互作用，并测试起始结构域是否在产生上下文相关活动方面发挥作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Multicellular organisms acquire their complex shapes through carefully controlled developmental processes. Key regulators of plant development include a class of proteins called transcription factors, which coordinate the specificity and function of plant cells and tissues. The action of some transcription factors are limited to only a few cells or a subset of tissues, but there are other factors that play key roles in a large number of developing tissues. This raises an interesting biological question: how can the same transcription factor generate different developmental outcomes? This project answers the question by identifying how the same transcription factor can serve different functions in various cells and tissues. The project combines techniques of genetics and biochemistry, including advances in high-resolution mapping of protein-protein interactions. Central to this proposal is the inclusion of students traditionally excluded from research-intensive insitituions. At The Ohio State University (OSU), this is manifested in Black students and students-of-color being overrepresented at OSU regional campuses, where research opportunities are limited. To mitigate this problem, undergraduates will be brought to the OSU Columbus main campus, provided food and lodging, paid a stipend, and enrolled in a 100-student consortium consolidating the various concurrent summer research programs. This pipeline broadens participation of traditionally excluded groups by eliminating the unfair choice between working a summer job and exploring research as a career.Biological development results from tightly controlled gene expression driven by the activity of transcription factors (TFs). TFs have been repeatedly coopted throughout evolution to regulate key developmental advances, in part because their outputs vary depending on developmental context. Mechanisms that generate these context-dependent readouts remain largely unknown, and this knowledge gap is particularly large in the plant kingdom. This gap will be addressed using CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) TFs as a model. HD-ZIPIII proteins are a particularly attractive model as they regulate a broad range of essential developmental processes, acting in tissues and organs ranging from meristems to roots to lateral organs. In addition, HD-ZIPIII protein architecture includes a StAR-related lipid transfer (START) domain. START domains are typically activated by lipophilic ligands and often mediate protein-protein interactions, presenting possible mechanisms to generate context-dependent activity. This proposal will test the genetic consequences and functional partnerships of the representative HD-ZIPIII PHABULOSA (PHB) in two functionally-distinct cell types: the indeterminate cells of the shoot apical meristem and the determinate cells of the adaxial side of leaves. Experiments including global genomic profiling and proximity labeling will identify meristem- and leaf-specific PHB gene regulatory networks and interactomes, and test whether the START domain plays a role in generating context-dependent activity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.