Temporal program for cell fate specification in the mouse embryo

小鼠胚胎细胞命运规范的时间程序

基本信息

批准号：
10223396
负责人：
Magdalena Zernicka-Goetz
金额：
$ 63.22万
依托单位：
CALIFORNIA INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10223396
关键词：
Actins Actomyosin Affect Apical Assisted Reproductive Technology Behavior Control Cell Cycle Cells Complex Cytoskeleton Data Defect Development Developmental Biology Dose Embryo Embryonic Development Ensure Event Experimental Models Fetus GATA3 gene Genetic Transcription Goals Human Imaging Techniques Inner Cell Mass Lead Light Link Mammals Mediating Medical Methods Modeling Morphogenesis Mus Myosin ATPase Nuclear Translocation Pharmacology Placenta Pregnancy loss Process Property Proteins Regenerative Medicine Reproduction Role Signal Transduction Testing Time Tissues To specify Totipotency Totipotent Up-Regulation Work base blastocyst cell fate specification cell type experimental study implantation insight mouse development natural Blastocyst Implantation novel optogenetics pluripotency polarized cell pregnancy failure pregnancy prevention preimplantation progenitor programs protein complex rho segregation self organization stem cell biology transcription factor zygote

项目摘要

SUMMARY. The first cell fate decision in mammals transforms a totipotent embryo comprising identical cells into two cell types: outer trophectoderm cells, which will give rise to the placenta, and inner pluripotent cells, which will give rise to the fetus. This decision depends on cell polarization. Although we understand how cell polarization connects to downstream signaling to specify the two cell types, the mechanisms that act earlier, to ensure cell polarization and its specific developmental timing, remain entirely unknown. To identify this mechanism, we first need to identify the upstream regulators, which have been elusive – until now. We recently found that two zygotically expressed transcription factors, Tfap2c and Tead4, together with Rho-mediated actomyosin activity, are essential and sufficient to trigger de novo cell polarization. These results provide us with an unprecedented opportunity to determine the mechanism that triggers the specific developmental timing of embryo polarization in early mammalian development. The objective of this proposal is to reveal the principles of self-organization that lead to de novo polarization and consequently the first cell fate specification in the key model mammalian embryo, the mouse embryo. Our central hypothesis is that zygotic transcription cooperates with the cytoskeleton to polarize cells and drive the first cell fate determination. We will test this hypothesis via the following Specific Aims: Aim 1: To determine what regulates timing of embryo polarization. We hypothesize that the timing of embryo polarization is controlled by Tfap2c and Tead4. We will alter the dose and developmental stage of Tfap2c and Tead4 expression and examine the effects on their downstream targets and the timing of embryo polarization. Aim 2: To determine how the apical domain becomes established. We hypothesize that Tfap2c and Tead4 regulate apical domain formation by modulating the actomyosin cytoskeleton, which in turn controls the conjugation of Par complex clusters. We will use advanced imaging techniques and pharmacological and optogenetic methods to determine the role of the actomyosin cytoskeleton in regulating apical domain formation and the dynamics of the Par complex during polarization. We will also examine how Tfap2c and Tead4 control the behavior of the actomyosin cytoskeleton and the organization of apical proteins into clusters to form the apical domain. Aim 3: To determine how altered timing of polarization affects embryo development. Embryo polarization always happens at the late 8-cell stage, just before the first cell fate decision, suggesting that the invariant timing of this polarization is critical for subsequent developmental progression. We will determine if accelerating the timing of embryo polarization by one cell cycle at the pre- implantation stage affects subsequent development, specifically cell fate and blastocyst formation before implantation and embryo morphogenesis post-implantation. We expect to discover the triggers and mechanisms that regulate the precise timing of cell polarization in the mouse embryo. Our work will likely have major medical relevance, as it will shed light on the causes of early developmental defects and pregnancy loss in humans.

概括。哺乳动物中的第一个细胞命运决策将完整的胚胎转化为完成相同的细胞两种细胞类型：外部滋养膜细胞，将产生plapeta和内部多能细胞，它们会产生。会引起胎儿。该决定取决于细胞极化。虽然我们了解细胞如何极化连接到下游信号，以指定两种单元类型，即早期起作用的机制确保细胞极化及其特定的发育时机仍然完全未知。确定这一点机制，我们首先需要确定一直难以捉摸的上游监管机构。我们最近发现两个合子表达的转录因子TFAP2C和TEAD4以及RHO介导的肌动球蛋白活性是必不可少的，足以触发从头细胞极化。这些结果为我们提供了一个前所未有的机会，可以确定触发特定发展时机的机制早期哺乳动物发育中的胚胎极化。该提议的目的是揭示原则导致从头极化的自组织，因此是钥匙中的第一个细胞脂肪规范模型哺乳动物胚胎，小鼠胚胎。我们的中心假设是合子转录合作用细胞骨架来极化细胞并驱动第一个细胞脂肪的测定。我们将通过以下特定目的：目标1：确定哪些调节胚胎极化的时间。我们假设胚胎极化的时间由TFAP2C和TEAD4控制。我们将改变剂量， TFAP2C和TEAD4表达的发育阶段，并检查对其下游目标的影响胚胎极化的时间。目标2：确定顶端域是如何建立的。我们假设TFAP2C和TEAD4通过调节肌动蛋白调节顶端结构域的形成细胞骨架，进而控制PAR复杂簇的结合。我们将使用高级成像确定肌动蛋白细胞骨架的作用的技术以及药物和光遗传学方法在控制顶部域的形成和极化过程中PAR复合物的动力学方面。我们也会检查TFAP2C和TEAD4如何控制肌动蛋白细胞骨架的行为和组织顶蛋白成簇以形成顶端结构域。目标3：确定极化的时间变化影响胚胎发育。胚胎极化总是发生在第一个阶段的8细胞阶段细胞脂肪的决策，表明这种极化的不变时间对于随后的发展至关重要进展。我们将确定是否在一个细胞周期中加速了胚胎极化的时间植入阶段会影响随后的发育，特别是细胞命运和胚泡形成植入后植入和胚胎形态发生。我们希望发现触发器和机制调节小鼠胚胎中细胞极化的精确时机。我们的工作可能会有大型医疗相关性，因为它将阐明人类早期发育缺陷和妊娠丧失的原因。