Analysis of the gene networks regulating the maternal to zygotic transition

描述(申请人提供)：母体向合子的转变是动物发育的普遍步骤，胚胎从母体驱动的程序过渡到合子程序。这需要清除母体提供的mRNAs，并转录合子基因。事实上，这两个过程是紧密相连的，母体因素驱动合子基因的激活，合子产物主动针对母体mRNAs进行去烯化、抑制和清除。这项建议旨在描述调节母体mRNAs清除和合子基因组激活的基因调控网络。通过将高通量测序与对早期胚胎的实验操作相结合，我们将定义不同的mRNA衰变波(目标1)和合子激活波(目标2)。利用计算分析和实验验证，我们将在转录和转录后水平上确定介导这一调控的基序，最终目标是确定导致这一调控的因素。这些拟议的实验将共同定义控制脊椎动物早期发育的基因调控网络。拟议的项目在不同层面上与公共卫生有关。首先，从人类疾病和癌症的角度来看，控制mRNA稳定的途径(包括miRNAs)在癌症中癌基因的异常激活中发挥着重要作用。通过评估控制早期胚胎中mRNA稳定性和转录激活的网络，这一建议为癌症的致癌表型提供了新的机制见解。其次，从生殖健康的角度来看，不孕不育估计会影响15% 育龄妇女和早孕丢失的比例相当于所有妊娠的25%，在体外受精后怀孕的比例高达70%。了解合子基因组激活和母体mRNA衰退的机制可以为人类不孕不育提供基本的见解，并为评估受精卵的早期损失提供工具。该项目的结果将有助于我们了解在母体向合子的转变过程中，早期胚胎中的基因表达是如何调节的，最终触发原肠形成和轴形成过程中不同发育途径的激活，从而导致合子的发育。 与公共卫生相关：在所有动物中，受精卵依赖于母亲向卵子提供的“指令”，以经历发育的第一个小时。受精后，卵子经历了两个普遍保守的步骤。首先，它需要激活自己的指令(基因组)的表达，其次，它需要消除母性指令(mRNAs和蛋白质)，以进入高级发育。这项建议研究了脊椎动物胚胎如何组织多个参与者来承担这些任务。

DESCRIPTION (provided by applicant): The maternal to zygotic transition is a universal step in animal development, where the embryo transitions from a maternally driven program to a zygotic program. This requires the clearance of the maternally provided mRNAs, and transcription of the zygotic genes. Indeed, these two processes are intimately interconnected, maternal factors drive the activation of the zygotic genes, and zygotic products actively target maternal mRNAs for deadenylation, repression and clearance. This proposal aims to characterize the gene regulatory networks that mediate clearance of the maternal mRNAs and activation of the zygotic genome. By combining high throughput sequencing with experimental manipulation of the early embryo, we will define distinct waves of mRNA decay (aim 1) and zygotic activation (Aim 2). Using computational analysis and experimental validation we will identify the motifs that mediate this regulation at the transcriptional and post-transcriptional level, with the ultimate goal of identifying the factors responsible for this regulation. Together these proposed experiments, will define the gene regulatory network that controls early vertebrate development. The proposed project is relevant for public health at different levels. First, from the stand point of human disease and cancer, pathways that control mRNA stability (including miRNAs) play an important role in aberrant oncogene activation in cancer. By assessing the networks that control mRNA stability and transcriptional activation in the early embryo, this proposal provides novel mechanistic insights into the oncogenic phenotype in cancer. Second, from the stand point of reproductive health, infertility is estimated to affect 15% of reproductive age women and early pregnancy loss corresponds to 25% of all pregnancies with up to 70% in pregnancies after in vitro fertilization. Understanding of the mechanisms of zygotic genome activation and maternal mRNA decay can provide fundamental insights in human infertility and tools to evaluate early loss of fertilized eggs. The results derived from thi project will help us understand how gene expression is regulated in the early embryo during the maternal to zygotic transition to ultimately trigger the activation of the different developmental pathways during gastrulation and axis formation resulting in zygote development. PUBLIC HEALTH RELEVANCE: In all animals, the fertilized egg depends on the "instructions" provided by the mom to the egg to undergo the first hours of development. Upon fertilization the egg undergo two universally conserved steps. First, it needs to activate the expression of its own instructions (genome), and second, it needs to eliminate the maternal instructions (mRNAs and proteins) to proceed into advanced development. This proposal studies how the vertebrate embryos organize multiple players to undertake these tasks.