Molecular Mechanisms of Myoblast Fusion

成肌细胞融合的分子机制

• 批准号: 7146437
• 负责人: Elizabeth H Chen
• 金额: $ 32.37万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7146437
• 关键词: Drosophilidae; Hymenoptera; actins; muscle; myoblasts; proteins

DESCRIPTION (provided by applicant): Skeletal muscle is a prime target organ for gene therapy, as engineered myoblasts can be introduced to fuse with mature muscle, forming a stable hybrid organ within the adults. The ability of injected satellite cells to fuse with myofibers directly affects the efficacy of cell-based gene therapy. Therefore, understanding the mechanisms controlling myoblast fusion promises to offer novel therapeutic possibilities in the future. We are using the fruit fly Drosophila as a genetic model to study the molecular mechanisms of myoblast fusion. Studies in recent years have revealed that many of the cellular and molecular events involved in muscle development are evolutionarily conserved between fly and vertebrates. This conservation has made it possible to dissect muscle differentiation using Drosophila genetics and to uncover essential genes required for myoblast fusion in flies and vertebrates. In a genetic screen for mutants in muscle development, we have identified a number of new loci required for myoblast fusion. To date, we have molecularly characterized two genes, antisocial and loner. Studies of these and other fusion genes have begun to reveal a signaling cascade controlling myoblast fusion. Antisocial is a novel adaptor protein that is localized to subcellular sites of fusion and relays the fusion signal from cell membrane to actin cytoskeleton. Loner, a guanine nucleotide exchange factor for ARF6, can also be recruited to sites of fusion. The goal of this project is to address two major questions concerning the mechanisms of myoblast fusion. First, how are fusion proteins recruited to sites of fusion by transmembrane receptors? Second, how is actin cytoskeletal rearrangement achieved during myoblast fusion? We propose a series of experiments to investigate the mechanisms by which Ants and Loner are targeted to sites of fusion. In Specific Aim I, we will identify domain(s) in Ants that are responsible for its localization to sites of fusion. In Specific Aim II, we will use biochemical and yeast two- hybrid approaches to isolate the intermediary protein(s) responsible for recruiting Loner to sites of fusion. In Specific Aim III, we propose the identification and characterization of a new component of the myoblast fusion machinery. We will examine its phenotype, localization, and interactions with known fusion proteins as well as with components of the actin cytoskeleton.

描述（由申请人提供）：骨骼肌是基因治疗的主要靶器官，因为可以引入工程的成肌细胞与成熟的肌肉融合，从而形成成人内部稳定的混合器官。注射的卫星细胞与肌膜融合的能力直接影响基于细胞基因疗法的功效。因此，了解控制肌细胞融合的机制有望将来提供新颖的治疗可能性。我们将果蝇果蝇作为遗传模型来研究成肌细胞融合的分子机制。近年来的研究表明，肌肉发育中涉及的许多细胞和分子事件在苍蝇和脊椎动物之间都是进化保守的。这种保护使使用果蝇遗传学的肌肉分化是可能的，并发现蝇和脊椎动物中成肌细胞融合所需的必需基因。在肌肉发育中突变体的遗传筛选中，我们已经确定了成肌细胞融合所需的许多新基因座。迄今为止，我们已经表征了两个反社会和孤独者的两个基因。这些和其他融合基因的研究已开始揭示控制肌细胞融合的信号级联。反社会是一种新型的衔接蛋白，它位于融合的亚细胞位点，并将融合信号从细胞膜转移到肌动蛋白细胞骨架上。 Loner是ARF6的鸟嘌呤核苷酸交换因子，也可以招募到融合部位。该项目的目的是解决有关肌细胞融合机制的两个主要问题。首先，如何通过跨膜受体募集融合蛋白化为融合的位点？其次，在肌细胞融合过程中如何实现肌动蛋白细胞骨架重排？我们提出了一系列实验，以研究蚂蚁和孤独者针对融合部位的机制。在特定的目标I中，我们将确定蚂蚁的域名域，这些域负责其定位到融合位置。在特定的目标II中，我们将使用生化和酵母两种杂交方法来隔离负责将LONER招募到融合部位的中介蛋白。在特定的目标III中，我们提出了成肌细胞融合机械的新组件的识别和表征。我们将检查其表型，定位和与已知融合蛋白以及肌动蛋白细胞骨架的成分的相互作用。