CAREER: microRNA-mediated regulation of dosage sensitive genes involved in morphogenesis

人类基因组大约有2万个基因，这些基因包含了产生蛋白质的信息，这些蛋白质在构成我们身体的细胞内和周围执行各种功能。为了人体和任何生物体的正确发育和功能，特定的蛋白质需要在特定的组织或器官中在特定的时间产生。同样重要的是，蛋白质以正确的水平产生，以实现其正常的细胞功能。许多被称为“剂量敏感基因”的基因产生的蛋白质对水平的变化非常敏感，这意味着这些蛋白质太多或太少都会对细胞有害，从而对活着的有机体有害。这些蛋白质水平的变化，可能是由于产生它们的基因拷贝太少或太多而引起的，通常会导致人类疾病。这个项目研究了一种机制，以确保基因不会产生过高的水平。研究人员在一个模型生物体中研究了这种类型的调节，这使得能够对不同条件下的发育和蛋白质生产进行定量和详细的检查。他们使用一种微小的线虫--线虫，在这种线虫中，他们可以修改基因，并在发育过程中测量产量。研究这些机制可以让我们了解为什么一些基因突变会导致疾病，并最终可能教会我们如何为了治疗目的而操纵基因剂量。基因组中的很大一部分基因是剂量敏感的，因此拷贝数变化(即使是单个基因组拷贝的丢失或增加)往往会导致疾病。识别能够实现精确基因表达水平的调控因子，对于全面理解基因调控和揭示疾病相关基因的修饰物至关重要。MicroRNAs(MiRNAs)是转录后水平的靶向mRNAs的定量抑制物，已有研究提出剂量敏感基因依赖于miRNA介导的调控。研究人员已经建立了一个实验范式，以在依赖于精确基因剂量的关键发育过程：动物形态发生的背景下测试这一点。MiR-100是保守程度最高的动物miRNA，存在于所有真核生物中。尽管它很保守，但miR-100在分子、细胞和组织中的作用几乎是未知的。研究人员建议使用线虫来研究这种古老动物miRNA的功能，并深入了解剂量敏感基因在发育过程中的调节。他们有证据表明，ECM成分是蠕虫、鱼、小鼠和人类中miR-100的保守靶标，这表明这种miRNA可能参与线虫以及其他动物的细胞信号和黏附。使用遗传学方法，研究人员将揭示这种古老的miRNA在线虫中的作用，基于共享的靶标对其在其他动物中的功能提供洞察，定义形态发生的剂量依赖调节因子的角色，并对miRNAs作为剂量敏感基因调节因子的贡献有新的理解。该奖项由综合组织系统部门的发展系统计划和生物科学理事会分子和细胞生物科学部门的遗传机制计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The human genome has about 20,000 genes, which contain the information to produce proteins that carry out a myriad of functions in and around the cells that make up our bodies. For the correct development and function of human bodies, and those of any organism, specific proteins need to be produced in specific tissues or organs, at specific times. It is also essential that proteins be produced at their correct levels to achieve their normal cellular functions. A number of genes called “dosage sensitive genes” produce proteins that are exquisitely sensitive to changes in level, meaning that too much or too little of these proteins is detrimental to the cells, and thus to the living organism. Changes in the level of these proteins, which may be caused by having too few or too many copies of the genes that produce them, often result in human disease. This project studies a mechanism for ensuring that genes are not produced at overly high levels. The researchers study this type of regulation in a model organism that enables a quantitative and detailed examination of development and of protein production under different conditions. They use a microscopic nematode, C. elegans, in which they can modify genes and measure the output during development. Studying such mechanisms can inform our understanding of why some gene mutations cause disease, and could ultimately teach us how to manipulate gene dosage for therapeutic purposes. A significant fraction of genes in a genome are dosage sensitive, such that copy number variation (loss or gain of even a single genomic copy) often results in disease. Identifying the regulators that enable precise gene expression levels is critical to fully understand gene regulation and to reveal modifiers of disease relevant genes. MicroRNAs (miRNAs) are quantitative repressors of target mRNAs at the post-transcriptional level and it has been proposed that dosage sensitive genes rely on miRNA-mediated regulation. The researchers have established an experimental paradigm to test this in the context of a key developmental process that relies on precise gene dosage: animal morphogenesis. miR-100 is the most deeply conserved animal miRNA, present across all Eumetazoa. Despite its conservation, the molecular, cellular and organismal roles of miR-100 are practically unknown. The researchers propose to use C. elegans to study the function of this ancient animal miRNA and gain insight into the regulation of dosage sensitive genes in development. They have evidence that ECM components are conserved targets of miR-100 in worms, fish, mice and humans, suggesting that this miRNA may be involved in cellular signaling and adhesion in C. elegans, and likely other animals. Using genetic approaches, the researchers will reveal the role of this ancient miRNA in C. elegans, provide insight into its function in other animals based on shared targets, define the role of a dosage dependent regulator of morphogenesis, and gain new understanding of the contribution of miRNAs as regulators of dosage sensitive genes.This award is co-funded by the Developmental Systems Program in the Integrative Organismal Systems Division and the Genetic Mechanisms Program in the Molecular and Cellular Biosciences Division of the Directorate for Biological Sciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.