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: 10552309
• 负责人: CHRISTINE A RUSHLOW
• 金额: $ 39.76万
• 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/10552309
• 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.

项目概要 受精后不久，基因组和转录组发生戏剧性的重新编程，从而使 果蝇胚胎尤其体现了这一点。 两小时内经历 13 个有丝分裂周期，使胚盘细胞化，塑造身体计划，并做好准备 虽然这些过程背后的基因网络已得到充分研究，但尚不清楚如何进行。 它们是共同启动的，这一过程被称为合子基因组激活。 观察到 DNA 复制发生在转录之前，但控制这一时间的机制尚不清楚。 此前，我们证明了单一因素 Zelda 可在全球范围内发挥作用来激活早期表达的基因。 发现 Zelda 与基因组中 CAGGTAG 位点的结合降低了增强子的核小体屏障， 促进其他关键转录因子的结合，从而存在于这些其他因子中。 我们的目标是使用高分辨率的亚核“中心”（离散焦点）。 此外，我们还通过显微镜研究了 Zelda 的哪些结构特征介导了枢纽的形成。 对控制转录和 DNA 复制时间的调节机制感兴趣，以便 我们建议塞尔达发挥双重先锋作用：1）开放。 染色质用于加载起始识别复合体并随后形成预复制复合体， 它会阻塞转录机制，直到起源被激发，并且 2) 打开新形成的染色质 我们的目标是首先定义早期胚胎的复制起点，并表征。 我们的研究将有助于解释塞尔达在起源许可和转录启动中的作用。 DNA 复制和转录过程在基因组激活过程中得到协调。