Developmental priming of mRNA decay during Drosophila embryogenesis

果蝇胚胎发生过程中 mRNA 衰退的发育启动

• 批准号: 10573021
• 负责人: Olivia Selfridge Rissland
• 金额: $ 19.23万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10573021
• 关键词: Alleles; Animals; Biological Models; Communities; Data Set; Deposition; Detection; Development; Dosage Compensation (Genetics); Drosophila genus; Drosophila melanogaster; Embryo; Embryonic Development; Ensure; Event; Excision; Exploratory/Developmental Grant; Female; Future; Genes; Genome; Goals; Grant; Hand; Length; Maintenance; Maternal Messenger RNA; Messenger RNA; Modeling; Modification; Molecular; Oogenesis; Play; Poly(A) Tail; Process; Production; Protein Isoforms; RNA; RNA-Binding Proteins; Regulation; Repression; Research; Role; Sex Chromosomes; Specific qualifier value; Tail; Testing; Transcript; Translations; computational pipelines; computerized tools; experience; experimental study; mRNA Decay; male; novel strategies; posttranscriptional; sex; sex determination; transcriptome

SUMMARY Destruction of deposited maternal transcripts is an essential step during early animal embryogenesis. Together with production of new zygotic transcripts, this process is called the maternal-to-zygotic transition (MZT) and enables the handover of developmental control from the maternal genome to the zygotic one. mRNA destruction is triggered by shortening of the 3' poly(A) tail, and control of tail length is an important post-transcriptional regulatory hub. However, we know little about the differences in poly(A)-tail lengths on maternal and zygotic transcripts. We propose a “developmental priming” hypothesis to bridge this conceptual gap: here, maternal transcripts experience oogenesis-specific poly(A)-tail shortening that leads to their destruction during the MZT. Developmental priming thus provides a mechanism whereby maternal and zygotic transcripts can be distinguished to enable the transfer of developmental control to the zygotic genome. In this proposal, we will test and explore this hypothesis using Drosophila as a model system. We will first focus on a potential archetype of developmental priming: the maternal Sex lethal (Sxl) mRNA. Sxl is a master regulator of sex determination and dosage compensation. Sex chromosome number leads to different male and female Sxl transcript isoforms, and the female isoform sets off an auto-regulatory, feed-forward loop that culminates in the maintenance of female identity. Importantly, the maternal (and thus female) Sxl mRNA is deposited in the embryo and must be removed lest it override the zygotic sex chromosome composition and lead to all embryos being specified as “female.” However, the molecular mechanism is unknown. We propose that the removal of maternal Sxl mRNA can be explained by developmental priming. In Aim 1, we will explore this model: during oogenesis the RNA-binding protein Bruno leads to short poly(A) tails on maternal Sxl mRNA and so primes them for destruction. In Aim 2, we will extend our hypothesis transcriptome- wide using a new approach that combines SNP-based allele detection with long-read sequencing to determine the poly(A)-tail lengths on maternal and zygotic transcripts. This second aim is exploratory and perfectly suited to the R21 mechanism. We expect our proposed research to make several significant contributions. First, it will provide an answer to a decades-old mystery about Sxl regulation during embryogenesis. Second, through our experiments in Aim 2, we will create high-quality long-read sequencing datasets spanning the Drosophila MZT. Third, we will develop a new experimental and computational tool that can use long-read sequencing to look at allele-specific regulation, which will enable future mechanistic experiments. Finally, it will provide a new conceptual framework for understanding the specific clearance of maternal transcripts, which will form the basis for future studies and grants. This intellectual framework will likely prove useful for understanding how old transcripts can be specifically regulated at other developmental transitions.

总结 在动物早期胚胎发生过程中，母体转录本的破坏是必不可少的一步。 这个过程与新合子转录本的产生一起被称为母体到合子的转变 (MZT)并使发育控制从母体基因组转移到合子基因组。 mRNA的破坏是由3' poly（A）尾的缩短触发的，控制尾长是重要的。 转录后调控中心。然而，我们对Poly（A）-尾长度的差异知之甚少， 母本和合子转录本。我们提出了一个“发展启动”假说来弥合这一概念 缺口：在这里，母体转录物经历卵子发生特异性poly（A）尾缩短，导致其 在MZT期间销毁。因此，发育启动提供了一种机制， 合子转录物可以被区分，以使发育控制转移到合子基因组。 在这个建议中，我们将测试和探索这一假设使用果蝇作为模型系统。我们将 首先关注发育启动的潜在原型：母体性致死（Sxl）mRNA。SXL是一个 性别决定和剂量补偿的主调节器。性染色体数目导致不同的 雄性和雌性Sxl转录物同种型，雌性同种型启动了一个自动调节的前馈回路 最终维护了女性身份重要的是，母体（因此也是女性）Sxl mRNA 沉积在胚胎中，必须去除，以免它覆盖合子性染色体组成 并导致所有胚胎被指定为“女性”。然而，其分子机制尚不清楚。我们 提出母体Sxl mRNA的去除可以通过发育启动来解释。目标1： 将探索这个模型：在卵子发生过程中，RNA结合蛋白布鲁诺导致短聚（A）尾巴上， 母体Sx 1 mRNA，因此引发它们的破坏。在目标2中，我们将扩展我们的假设转录组- 广泛使用一种新方法，将基于SNP的等位基因检测与长读测序相结合来确定 母体和合子转录物上的poly（A）尾长度。第二个目标是探索性的， R21机制。 我们希望我们提出的研究能够做出一些重大贡献。首先，它将提供一个 这是一个关于胚胎发生过程中Sxl调控的几十年之谜的答案。第二，通过我们的 在目标2的实验中，我们将创建跨越果蝇的高质量长读段测序数据集。 MZT第三，我们将开发一种新的实验和计算工具， 来研究等位基因特异性调节，这将使未来的机械实验成为可能。最后，它将提供一个 新的概念框架，了解具体清除产妇成绩单，这将形成 为今后的学习和赠款奠定基础。这个知识框架可能会被证明有助于理解 在其他发育转变中，旧的转录本如何被特异性地调节。