The Role of Cap Z in Sarcomere Organization and Function in Drosophila

米勒9419106调节肌动蛋白组装的机制负责赋予细胞形态和功能。肌动蛋白是一种蛋白质，它有助于支持细胞内的结构和导致收缩的机制，因此它是肌肉细胞存在和功能的核心。这项建议研究肌肉细胞的形成和调节机制。从技术上讲，对高等生物的肌肉细胞进行这项研究是不可能的，因为基因操作的能力是不可能的。PI使用果蝇肌肉发育作为分析的模型系统。该系统是用于真核细胞遗传分析的种子系统，可以很容易地用于涉及遗传操作的研究。由于肌细胞组织在真核生物中高度保守，因此该系统的结果很容易被推广到其他真核细胞中。PI感兴趣的是肌动蛋白聚合是如何控制的，以及在真核生物中不同类型的细胞中不同的肌动蛋白结构是如何形成和定位的。特别令人感兴趣的是肌肉肌节的组装过程。肌动蛋白细丝呈高度规则的排列，其位置和组织对肌肉功能至关重要。为了了解这种规则排列的肌动蛋白细丝是如何产生的，PI正在研究肌动蛋白结合蛋白，Cap Z是一种异二聚体蛋白(α和β亚基)，它在体外与肌动蛋白细丝的带刺(快速生长)端结合并阻止聚合。它位于脊椎动物肌肉的Z线上，肌动蛋白细丝的带刺末端终止并锚定。CaP Z的体外性质及其在肌肉中的定位表明，它是控制肌动蛋白聚合和/或锚定肌动蛋白细丝的关键成分。然而，它在体内的作用还缺乏确凿的证据。PI将通过对果蝇中编码Z帽亚单位之一(Beta)的基因进行突变，获得肌肉肌动蛋白细丝组织是如何产生的直接信息，特别是Z帽的作用。果蝇是研究肌肉功能的一个有吸引力的模型系统，因为它的肌肉组织类似于脊椎动物的肌肉，但它可以使用脊椎动物难以或不可能使用的基因技术进行操作。PI将研究Z帽β突变果蝇肌肉的发育、组织和功能，并研究Z帽在携带其他肌节成分突变的果蝇中的分布。通过这些研究，PI将确定肌肉的不同蛋白质如何相互作用来产生其结构。这些研究应该适用于各种各样的生物体*

Miller 9419106 The mechanisms which regulate actin assembly are responsible for giving both form and function to cells. Actin is a protein which contributes to support structures within the cell and to mechansims which cause contraction, and consequently it is central to the existence and function of muscle cells. This proposal investigates the formation of, and regulatory mechanisms in, muscle cells. It would be technically impossible to conduct this studies on muscle cells from higher organisms because the ability for genetic manipulation is not possible. The PI uses Drosophila muscle development as a model system for the analysis. This system is the seminal system for genetic analysis in eukaryotic cells and can easily be employed for studies involving genetic manipulation. Since muscle cells organization is highly conserved among eukaryotics results from this system are anticipated to be easily extrapolated to other eukaryotic cells %%% The PI is interested how actin polymerization is controlled and how different actin-containing structures are formed and positioned in many different types of cells in eukaryotic organisms. Of particular interest is the process of muscle sarcomere assembly. A highly regular array of actin filaments is present, the location and organization of which is essential to muscle function. To understand how this regular array of actin filaments is generated, the PI is studying the actin binding protein, Cap Z. Cap Z is a heterodimeric protein (alpha and beta subunits) that binds to and blocks polymerization at the barbed (fast-growing) end of an actin filament in vitro. It is located at the Z-line of muscle in vertebrates, where the barbed end of actin filaments terminate and are anchored. Cap Z's properties in vitro and its localization in muscle suggest that it is a key component in controlling actin polymerization and/or anchoring actin filaments. However, definitive evidence for its function in vivo is lacking. The PI will obtain direct inform ation about how the actin filament organization of muscle is generated and in particular, the role of Cap Z, by making mutations in the gene that encodes one of the Cap Z subunits (beta) in the fruit fly, Drosophila. Drosophila is an attractive model system for studies on muscle function because its muscles are organized similarly to vertebrate muscles, yet it can manipulated using genetic techniques that are difficult or impossible in vertebrates. The PI will study the development, organization and function of muscles in Cap Z beta mutant flies and study Cap Z's distribution in flies that carry mutations in other sarcomere components. Through these studies the PI will determine how different proteins of the muscle interact to generate its structure. These studies should be applicable to a wide variety of organisms ***