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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：
10657581
负责人：
Magdalena Zernicka-Goetz
金额：
$ 54.68万
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/10657581
关键词：
Acceleration Actins Actomyosin Affect Apical Assisted Reproductive Technology Behavior Control Cell Cycle Cells Complex Cytoskeleton Data Defect Development Developmental Biology Dose Embryo Embryonic Development Embryonic Induction Ensure Event Experimental Models Fetus GATA3 gene Genetic Transcription Goals Human Imaging Techniques Inner Cell Mass Link Mammals Mediating Medical Methods Modeling Morphogenesis Mus Myosin ATPase Nuclear Translocation Placenta Pregnancy loss Process Property Proteins Regenerative Medicine Reproduction Role Signal Transduction Specific qualifier value Testing Time Totipotency Totipotent Up-Regulation Work blastocyst cell fate specification cell type embryo tissue experimental study implantation insight mouse development natural Blastocyst Implantation novel optogenetics pharmacologic 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.

总结。哺乳动物的第一个细胞命运决定将包含相同细胞的全能胚胎转化为两种细胞类型：滋养外胚层细胞和内多能细胞，滋养外胚层细胞形成胎盘会孕育出胎儿。这一决定取决于细胞极化。尽管我们了解细胞如何极化连接到下游信令，以指定两种细胞类型，即较早作用的机制，以确保细胞极化及其特定的发育时间仍然完全未知。要确定这一点机制方面，我们首先需要确定上游监管机构，到目前为止，这些监管机构一直难以捉摸。我们最近发现两个合子转录因子Tfap2c和Tead4与Rho共同介导表达肌动球蛋白活性，是触发从头细胞极化的必要条件和充分条件。这些结果为我们提供了这是一个前所未有的机会来确定触发特定发育时机的机制哺乳动物早期发育中的胚胎极化。这项建议的目的是揭示原则导致从头极化的自组织，并因此在密钥中第一个细胞命运规范模范哺乳动物胚胎，小鼠胚胎。我们的中心假设是合子转录协同作用用细胞骨架来极化细胞，并驱动第一个细胞命运的决定。我们将通过以下方式验证这一假设具体目标如下：目标1：确定是什么调节了胚胎极化的时间。我们假设胚胎极化的时间由Tfap2c和Tead4控制。我们会改变剂量和 Tfap2c和Tead4表达的发育阶段及其对其下游靶和蛋白表达的影响胚胎极化的时间。目的2：确定顶域是如何建立的。我们假设Tfap2c和Tead4通过调节肌动球蛋白调节顶端结构域的形成细胞骨架，它反过来控制PAR复合簇的共轭。我们将使用先进的成像技术确定肌动蛋白细胞骨架作用的技术及药理学和光遗传学方法在调节顶端结构域的形成和极化过程中PAR复合体的动态。我们还将研究Tfap2c和Tead4如何控制肌动蛋白细胞骨架的行为和组织顶端蛋白形成簇，形成顶端区域。目标3：确定极化时间的改变影响胚胎发育。胚胎极化总是发生在8-细胞的晚期，恰好在第一个细胞之前。细胞命运的决定，表明这种极化的不变时间对随后的发育至关重要进步。我们将确定是否将胚胎极化的时间提前一个细胞周期着床阶段影响随后的发育，特别是细胞命运和胚泡的形成。植入和植入后胚胎形态发生。我们希望发现触发因素和机制调节小鼠胚胎细胞极化的精确时间。我们的工作很可能会有重大的医疗相关性，因为它将阐明人类早期发育缺陷和妊娠丢失的原因。