Pioneer factor activity in transcription and DNA replication

转录和 DNA 复制中的先锋因子活性

• 批准号: 10822405
• 负责人: CHRISTINE A RUSHLOW
• 金额: $ 1.16万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10822405
• 关键词: Binding; Blastoderm; Body Patterning; Chromatin; Complex; DNA biosynthesis; DNA replication origin; Development; Developmental Process; Drosophila genus; Embryo; Enhancers; Event; Fertilization; Genes; Genetic Transcription; Genome; Goals; Hour; Licensing; Mediating; Microscopy; Mitotic; Nucleosomes; Organism; Play; Pre-Replication Complex; Process; Replication Origin; Resolution; Role; Site; Testing; Transcription Initiation; Transcriptional Activation; gastrulation; gene network; interest; origin recognition complex; transcription factor; transcriptome

PROJECT SUMMARY Shortly after fertilization, a dramatic reprogramming of the genome and transcriptome occurs, enabling the embryo to develop quickly and robustly. This is especially exemplified in the Drosophila embryo, which within a two-hour period undergoes 13 mitotic cycles, cellularizes the blastoderm, patterns the body plan, and gets ready for gastrulation. While the gene networks underlying these processes have been well studied, it is not clear how they are collectively initiated, a process referred to as zygotic genome activation. Moreover, although it was observed that DNA replication occurs before transcription, the mechanisms that control this timing are not known. Previously, we demonstrated that a single factor, Zelda, acts globally to activate early-expressed genes. We found that Zelda binding to CAGGTAG sites across the genome lowers nucleosome barriers at enhancers, thereby facilitating the binding of other key transcription factors. Zelda and these other factors are present in sub-nuclear “hubs” (discrete foci) that were seen to colocalize at enhancers. We aim to use high-resolution microscopy to investigate the which structural features of Zelda mediate hub formation. In addition, we are interested in the regulatory mechanisms that control the timing of transcription and DNA replication so that conflicts between the two processes are avoided. We propose that Zelda plays a dual pioneering role: 1) to open chromatin for the Origin Recognition Complex to load and subsequent formation of the Pre-replication Complex, which occludes the transcriptional machinery until origins have fired, and 2) to open newly formed chromatin for transcription to initiate. Our goal is to first define origins of replication in early embryos, and to characterize Zelda's role in origin licensing and transcriptional initiation. Our studies will lend into how these two fundamental processes of DNA replication and transcription are coordinated during genome activation.

项目摘要 受精后不久，发生了基因组和转录组的戏剧性重编程，使得能够 胚胎快速，稳健地发展。这在果蝇胚胎中尤其举例说明 两个小时的时期经历13个有丝分裂循环，细胞化胚胚层，对身体计划进行模式，并准备就绪 用于过度。尽管这些过程的基因网络已经很好地研究了，但尚不清楚如何如何 它们统称为启动，这一过程称为合子基因组激活。而且，尽管是 观察到DNA复制发生在转录之前，控制该时间的机制尚不清楚。 以前，我们证明了一个单一因素Zelda在全球起作用以激活早期表达的基因。我们 发现Zelda与基因组跨基因组的CAGGTAG位点结合可在增强子处降低核小体屏障， 从而支持其他关键转录因子的结合。 Zelda和这些其他因素存在 可在增强子上共定位的核核“集线器”（离散焦点）。我们的目标是使用高分辨率 显微镜研究Zelda介导轮毂形成的结构特征。此外，我们是 对控制转录和DNA复制时间的调节机制感兴趣，以便 避免了两个过程之间的冲突。我们建议Z​​elda扮演双重开创性的角色：1） 原始识别复合物的染色质，用于负载和随后的复制复合物的形成， 它阻塞了转录机械，直到起源发射为2） 转录开始。我们的目标是首先定义早期胚胎复制的起源，并表征 Zelda在起源许可和转录倡议中的作用。我们的研究将介绍这两个基本 在基因组激活期间，DNA复制和转录过程协调。