Mechanisms of Mitotic Fidelity

项目概要 有丝分裂的主要目标是在两个子细胞之间准确分配遗传物质。缺陷 减数分裂或有丝分裂导致非整倍体，这是出生缺陷的一个重要原因，也是 肿瘤发生。这一过程的关键是有丝分裂纺锤体，它是一种细胞大分子机器 负责遗传物质的对齐和分离。尽管主轴结构和 分子参与者在生物体中高度保守，纺锤体和蛋白质的详细组织 甚至生物体内不同类型的细胞的功能也可能有所不同。这种变异表明细胞已经进化 多种途径确保遗传物质的正确分布。我的实验室长期以来对 了解分子运动蛋白如何组织纺锤体结构，调节微管动力学 纺锤体，有助于有丝分裂期间准确的染色体分离。这些研究很重要 因为运动蛋白不仅在纺锤体组织和功能中发挥着基础作用，而且还因为 它们通常在癌细胞中过度表达，可能是治疗开发的有价值的靶点。在 未来五年，我们的研究将集中在三个关键问题上。 1) 分子运动活动在空间上和 暂时监管？一个重要的目标不仅是了解分子马达如何单独发挥作用， 还包括电机组如何与其结合伙伴合作来调节主轴功能。我们的研究 将定义电机的生化活动和该活动的细胞读数之间的关键网络。 2） 受调控的微管动力学和中心体聚类如何增强有丝分裂的保真度？目前的 模型是癌细胞产生低水平的非整倍性以驱动其生存，同时限制严重的 非整倍体将确保细胞死亡。我们将通过以下方式揭示关键分子马达如何影响有丝分裂保真度 剖析它们在有丝分裂和 DNA 损伤修复中的功能。此外，我们将研究中心体如何 聚类限制了具有扩增中心体的细胞中的严重非整倍性。 3）染色体如何准确 倍性改变的细胞中染色体负荷增加会影响分离吗？一个重要的但是 未充分研究的问题是阐明细胞蛋白质的正常补体如何处理非整倍性 正常细胞和癌细胞以及关键参与者相对表达水平的变化如何影响 遗传物质的准确分离。我们将利用我们的能力来生成细胞 不同水平的倍性，以了解关键分子马达的表达变化如何受到影响 染色体负荷增加及其如何影响有丝分裂保真度。我们提出的研究利用了我们的 关键分子工具箱、严格的生化检测、高质量成像和多样化的模型系统 定义控制有丝分裂保真度的马达和调节网络的功能。这些研究的结果 将定义不同的蛋白质-蛋白质相互作用网络影响纺锤体形态发生的机制 并将为细胞如何维持基因组完整性提供新的见解。

Project Summary The major goal of mitosis is to distribute the genetic material accurately between two daughter cells. Defects in meiosis or mitosis lead to aneuploidy, which is a significant cause of birth defects and is a hallmark of tumorigenesis. Critical to this process is the mitotic spindle, which is a cellular macromolecular machine tasked with both alignment and segregation of the genetic material. Even though the spindle structure and molecular players are highly conserved across organisms, the detailed organization of the spindle and protein function can vary even between cell types within an organism. This variation suggests that cells have evolved multiple pathways to ensure the proper distribution of genetic material. My lab has a long-standing interest in understanding how molecular motor proteins organize spindle structure, regulate microtubule dynamics in the spindle, and contribute to accurate chromosome segregation during mitosis. These studies are important because motor proteins not only play fundamental roles in spindle organization and function, but also because they are often overexpressed in cancer cells and may be valuable targets for therapeutic development. In the next five years, our studies will focus on three key questions. 1) How is molecular motor activity spatially and temporally regulated? An important goal is to understand not only how molecular motors function individually, but also how groups of motors cooperate with their binding partner to regulate spindle function. Our studies will define critical networks between biochemical activities of motors and cellular readouts of that activity. 2) How do regulated microtubule dynamics and centrosome clustering enhance mitotic fidelity? The current model is that cancer cells generate low levels of aneuploidy to drive their survival while limiting severe aneuploidy that would ensure cell death. We will uncover how key molecular motors impact mitotic fidelity by dissecting their function in mitosis and DNA damage repair. In addition, we will examine how centrosome clustering restricts severe aneuploidy in cells with amplified centrosomes. 3) How is accurate chromosome segregation impacted by increased chromosome load in cells with altered ploidy? An important but understudied problem is to elucidate how the normal complement of cellular proteins handles aneuploidy in both normal and cancer cells and how changes in the relative expression levels of key players impact accurate segregation of the genetic material. We will take advantage of our ability to generate cells with different levels of ploidy to understand how changing expression of key molecular motors is impacted by increased chromosome load and how that affects mitotic fidelity. Our proposed studies take advantage of our toolbox of key molecules, rigorous biochemical assays, high quality imaging, and diverse model systems to define the function of motors and regulatory networks that control mitotic fidelity. The outcome of these studies will define mechanisms by which distinct protein-protein interaction networks impact spindle morphogenesis and will provide new insights into how cells maintain genome integrity.