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

人类基因组大约有2万个基因，这些基因包含着产生蛋白质的信息，这些蛋白质在构成我们身体的细胞内部和周围执行着无数的功能。为了人体和任何生物的正常发育和功能，特定的蛋白质需要在特定的时间在特定的组织或器官中产生。同样重要的是，蛋白质必须以正确的水平产生，才能实现正常的细胞功能。许多被称为“剂量敏感基因”的基因产生的蛋白质对剂量水平的变化非常敏感，这意味着这些蛋白质过多或过少对细胞有害，从而对生物体有害。这些蛋白质水平的变化，可能是由产生它们的基因拷贝过少或过多引起的，往往导致人类疾病。该项目研究了一种机制，以确保基因不会以过高的水平产生。研究人员在一种模式生物中研究了这种类型的调节，这种模式生物可以定量和详细地检查不同条件下的发育和蛋白质生产。他们使用一种微小的线虫，秀丽隐杆线虫，他们可以在其中修改基因，并在发育过程中测量输出。研究这种机制可以让我们了解为什么一些基因突变会导致疾病，并最终教会我们如何操纵基因剂量以达到治疗目的。基因组中很大一部分基因是剂量敏感的，因此拷贝数变异（即使是单个基因组拷贝的丢失或获得）往往导致疾病。确定能够精确表达基因水平的调控因子对于充分理解基因调控和揭示疾病相关基因的修饰因子至关重要。MicroRNAs （miRNAs）是靶mrna转录后水平的定量抑制因子，已经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例，在一个依赖于精确基因剂量的关键发育过程的背景下测试这一点：动物形态发生。miR-100是最保守的动物miRNA，存在于所有真生动物中。尽管其保守性，miR-100的分子、细胞和机体作用实际上是未知的。研究人员建议利用秀丽隐杆线虫来研究这种古老动物miRNA的功能，并深入了解发育过程中剂量敏感基因的调控。他们有证据表明，在蠕虫、鱼类、小鼠和人类中，ECM成分是miR-100的保守靶点，这表明该miRNA可能参与秀丽隐杆线虫和其他动物的细胞信号传导和粘附。利用遗传学方法，研究人员将揭示这种古老的miRNA在秀丽隐杆线虫中的作用，基于共享靶标，深入了解其在其他动物中的功能，定义形态发生的剂量依赖调节剂的作用，并获得miRNA作为剂量敏感基因调节剂的贡献的新认识。该奖项由生物科学理事会综合有机体系统部的发展系统项目和分子与细胞生物科学部的遗传机制项目共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.