Temporal control of cell patterning, signaling, and movement in early embryos

早期胚胎细胞模式、信号传导和运动的时间控制

• 批准号: 10445335
• 负责人: Angelike Stathopoulos
• 金额: $ 62.31万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-11 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10445335
• 关键词: Actins; Adherens Junction; Animals; Blastoderm; Cell physiology; Cells; Cellular Morphology; Chromatin; Comparative Study; Cytoskeleton; Data; Development; Dominant-Negative Mutation; Dorsal; Drosophila genus; Embryo; Embryonic Development; Enhancers; Fibroblast Growth Factor; Funding; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Goals; Homologous Gene; Hour; Image; Ligands; Movement; NF-kappa B; Output; Pattern; Process; Regulatory Element; Research; Series; Signal Pathway; Signal Transduction; Signaling Molecule; Supporting Cell; System; Time; Tissues; Transcript; Variant; Work; cell motility; combinatorial; epithelial to mesenchymal transition; experimental study; gastrulation; in vivo imaging; insight; morphogens; preimplantation; programs; transcription factor

Regulation of gene expression along the dorsal-ventral (DV) axis of Drosophila embryos serves as a paradigm of developmental patterning. Comparative studies of cis-regulatory elements that support expression along the DV axis from many research groups have made it clear that combinatorial input into enhancers by multiple transcription factors drives distinct spatial-outputs of gene expression. A pivotal regulator of this patterning process is the maternally-provided transcription factor Dorsal (Dl), homolog of NFKB. Dl functions as a morphogen to activate target gene expression in a concentration-dependent manner along the DV axis, contributing to the initiation of zygotic gene expression at the maternal-to-zygotic transition (MZT). Using live imaging, we quantified the Dl gradient in embryos and found, surprisingly, that levels change not only in space but also build in time. Our focus during the previous funding period was to study the impact of these Dl dynamics on target gene expression using quantitative approaches involving analysis of live imaging or fixed embryo time-series data to provide insight. In the current proposal, we follow three new and exciting directions, which relate to the timing of cell actions in early embryos and arose as a result of the previous work. Project 1 involves studying how broadly-expressed activators and repressors cooperate to control the onset of zygotic gene expression during the MZT. We hypothesize that broadly-expressed repressors are equally important to pioneer activators in the control of chromatin accessibility and thereby also regulate initiation of zygotic gene expression. Project 2 focuses on dissecting the function of short-transcripts for long genes that are expressed specifically in the early syncytial embryo. We hypothesize that these short transcripts act to regulate timing of cell signaling pathway activation by functioning as dominant-negative variants of signaling molecules. Project 3 focuses on identifying the mechanism by which FGF signaling regulates adherens junctions (AJs) and their interaction with the actin cytoskeleton to contribute to the first epithelial-to-mesenchymal transition (EMT) in embryos; in particular, to understand how a degron associated with one FGF ligand, Pyramus, limits signaling time. The overarching goal of the proposed research program is to understand how the timing of these cell activities - patterning, signaling, and movement - are controlled in developing Drosophila embryos and to provide general insights applicable to higher animals. While many studies have focused on spatial outputs of gene expression, less is known about the temporal dynamics of patterning. Drosophila embryos are a tractable system to study MZT as it occurs in 3-4 hours, in contrast to taking days in preimplantation mammalian embryos. The Drosophila embryo is also amenable to live in vivo imaging and tracking analyses making it well-suited to the study of nascent transcription and cell morphology. Lastly, our proposed studies will provide general insight into early embryo development of higher animals as many regulatory mechanisms are likely conserved.

调节果蝇胚胎的背腹侧（DV）轴的基因表达用作 发展模式的范式。顺式调节元素的比较研究 许多研究小组沿DV轴的支持表达清楚地表明 通过多种转录因子驱动不同的驱动器的组合输入到增强子中 基因表达的空间输出。此模式过程的关键调节器是 母体提供的转录因子背侧（DL），NFKB同源物。 DL功能为 形态学以沿着浓度依赖性方式激活靶基因表达 DV轴，有助于在 母亲到杂种过渡（MZT）。使用实时成像，我们量化了胚胎中的DL梯度 令人惊讶的是，该水平不仅在太空中变化，而且在及时建立。我们的 在上一个资金期间的重点是研究这些DL动态对目标的影响 使用涉及分析活成像或固定胚胎的定量方法的基因表达 时间序列数据可提供洞察力。在当前的提案中，我们遵循三个新的令人兴奋的 与早期胚胎中细胞动作的时机有关的方向，并因 以前的工作。项目1涉及研究如何宽广的激活因子和阻遏物 合作以控制MZT期间的二聚基因表达的发作。我们假设这一点 广泛表达的阻遏物对先驱激活剂的控制同样重要 染色质的可及性，从而调节二聚基因表达的起始。项目2 专注于剖析表达的长基因的短转录功能 特别是在早期合成胚胎中。我们假设这些简短的成绩单是 通过充当主导性变体来调节细胞信号通路的激活时间 信号分子。项目3专注于识别FGF信号的机制 调节粘附连接（AJS）及其与肌动蛋白细胞骨架的相互作用以贡献 到胚胎中的第一个上皮到间质转变（EMT）；特别是了解 degron与一个FGF配体（Pyramus）如何限制信号时间。总体目标 拟议的研究计划是了解这些细胞活动的时间如何 - 在果蝇胚胎中控制模式，信号和运动。 并提供适用于高等动物的一般见解。许多研究重点是 基因表达的空间输出，对图案的时间动力学知之甚少。 果蝇胚胎是一个可在3-4小时内研究MZT的可进行的系统 与植入前哺乳动物胚胎中花费几天的形成对比。果蝇胚胎是 也可以生活在体内成像和跟踪分析中，使其非常适合研究 新生的转录和细胞形态。最后，我们提出的研究将提供一般 洞悉高等动物的早期胚胎发展，因为许多调节机制可能是 保守。