Mechanisms of mRNA localization and translational control in Drosophila development

项目总结 我们的长期目标是了解在空间和时间上控制基因的转录后机制 动物发育过程中的活动。我们专注于细胞内信使核糖核酸的定位、翻译控制和 降解，这在调节从母体提供的转录本中产生蛋白质方面起着关键作用。 这些转录本是几乎所有动物最初发育计划的基础，它们预先加载在 蛋。因此，对它们在哪里以及何时部署以生产蛋白质的控制必须在 从转录上讲。我们的研究利用了高度可操控的果蝇模型，该模型严重依赖于 母体转录本，以研究产生不对称母体mRNA和蛋白质的机制 胚胎体型和生殖系发育所需的分布。我们之前的工作表明， 在果蝇卵母细胞的后部，大量的mRNA通过与大的， 非膜结合的核糖核蛋白(RNP)组装称为胚泡。在胚胎发育过程中，细菌 颗粒将这组mRNAs传递到原始生殖细胞，在那里它们支持生殖系的发育。 生殖细胞颗粒是整个动物界原始生殖细胞的标志。它们含有保守的 表明在RNA调节中具有共同功能的成分，以促进分化、增殖和 生殖系的维护。细菌颗粒只是众多细胞RNP组件中的一个 因其相变行为而被表征。RNA背景下的mRNA调控是如何发生的 然而，更一般的颗粒及其生物学意义仍然知之甚少。因为复杂和 在生物学上相关的RNP组件，细菌颗粒是研究RNA定位、翻译 控制和退化，特别是它们的生物学意义。我们的研究导致了细菌的模型 通过自我招募和组织成同型簇来颗粒“客户”RNA的积累。这款车 提供了一个框架来研究mRNAs如何在颗粒中自组织以及这种组织如何传递 对共享颗粒内不同mRNAs翻译和稳定性的选择性控制。我们将联合起来 具有强大的生化和遗传/基因组策略的定量高分辨率成像，以及新颖的 扰乱颗粒物的方法，调查颗粒物客户组织的基本原则 RNA。这些研究将使我们能够破译颗粒联想、翻译和翻译之间的关系 活力性和胚芽颗粒功能。鉴于转录后机制在 发展，以及颗粒中RNA区域化的流行，这项工作将产生广泛的影响。 从我们的研究中获得的机械论见解也将为理解RNA中的缺陷提供基础 代谢与许多疾病有关，包括不孕不育、癌症和神经退化。

PROJECT SUMMARY Our long-term goal is to understand post-transcriptional mechanisms that spatially and temporally control gene activity during animal development. We focus on intracellular mRNA localization, translational control, and degradation, which play crucial roles in regulating production of proteins from maternally supplied transcripts. These transcripts, which underpin the initial developmental program of nearly all animals, are pre-loaded in the egg. Thus, control over where and when they are deployed to produce protein must be exerted post- transcriptionally. Our research capitalizes on the highly manipulable Drosophila model, which relies heavily on maternal transcripts, to investigate mechanisms that generate asymmetric maternal mRNA and protein distributions needed for embryonic body patterning and germline development. Our previous work revealed that numerous mRNAs accumulate at the posterior of the Drosophila oocyte through their incorporation into large, non-membrane-bound ribonucleoprotein (RNP) assemblies called germ granules. During embryogenesis, germ granules deliver this cohort of mRNAs to the primordial germ cells, where they support germline development. Germ granules are a hallmark of primordial germ cells throughout the animal kingdom. They contain conserved components that indicate a common function in RNA regulation to promote the differentiation, proliferation, and maintenance of the germline. Germ granules are just one of a plethora of cellular RNP assemblies that have been characterized for their phase-transitioned behavior. How mRNA regulation occurs in the context of RNA granules more generally and its biological significance remain, however, poorly understood. As complex and biologically relevant RNP assemblies, germ granules are ideal for studying RNA localization, translational control, and degradation and, in particular, their biological significance. Our studies lead to a model for germ granule "client" RNA accumulation by self-recruitment and organization into homotypic clusters. This model provides a framework to investigate how mRNAs self-organize in granules and how this organization imparts selective control over the translation and stability of different mRNAs within shared granules. We will combine quantitative high resolution imaging with powerful biochemical and genetic/genomic strategies, as well as novel methods that disrupt granules, to investigate fundamental principles governing the organization of granule client RNAs. These studies will enable us to decipher the relationship between granule association, translational activity, and germ granule function. Given the widespread use of post-transcriptional mechanisms during development, and the prevalence of RNA compartmentalization in granules, this work will have broad impact. Mechanistic insights gained from our studies will also provide a foundation for understanding defects in RNA metabolism associated with numerous disorders including infertility, cancer, and neurodegeneration.