Developmental Regulation of the Cell Cycle in Drosophila

果蝇细胞周期的发育调控

基本信息

批准号：
7887404
负责人：
LAURA ANNE LEE
金额：
$ 29.79万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-04-01 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7887404
关键词：
Acetylation Acetyltransferase Animal Model Appearance Binding Biological Process Brain Cell Cycle Cell Cycle Regulation Cell Nucleus Cell division Cells Centrioles Centrosome Chimeric Proteins Chromosome Segregation Complex Coupling Cytokinesis Cytology Cytoplasm DNA Data Defect Development Differentiation and Growth Drosophila genus Drosophila melanogaster Dynein ATPase Employee Strikes Event Exhibits Funding Gametogenesis Genetic Germ Cells Haploidy Homologous Gene Human Image Analysis Intracellular Transport Knowledge LIS1 protein Life Malignant Neoplasms Mediating Meiosis Microtubules Mitosis Mitotic Modeling Motor Movement Mus Nuclear Nuclear Pore Complex Organism Pattern Phenotype Phosphorylation Site Process Prophase Proteins Proteolysis Recruitment Activity Regulation Relative (related person)Reporting Role Site Somatic Cell Spermatids Spermatocytes Spermatogenesis Surface System Tertiary Protein Structure Testing Testis Time Tubulin Yeasts cell motility dynactin gene conservation human disease insight kinetosome male mutant programs public health relevance research study sperm cell yeast two hybrid system

项目摘要

DESCRIPTION (provided by applicant): The high degree of functional conservation of genes involved in the cell cycle combined with the superb genetics and cytology of Drosophila melanogaster make it an ideal model organism for studying cell-cycle regulation in a developmental context. Spermatogenesis utilizes mitotic and meiotic cell cycles coordinated with growth and differentiation programs to generate functional sperm. By mutational analysis, we have identified asunder (asun), which encodes an evolutionarily conserved protein, as an essential regulator of Drosophila spermatogenesis. asun spermatocytes arrest during prophase of meiosis I. Strikingly, arrested spermatocytes contain free centrosomes that fail to stably associate with the nucleus. Spermatocytes that overcome arrest exhibit severe defects in meiotic spindle assembly, chromosome segregation, and cytokinesis. Furthermore, the centriole-derived basal body is detached from the nucleus in asun postmeiotic spermatids, resulting in abnormalities later in spermatogenesis. We find that asun spermatocytes and spermatids exhibit drastic reduction of perinuclear dynein. Dynein is a minus end-directed microtubule motor complex that is required for diverse biological processes, from transport of intracellular cargo to cell migration. Dynein is controlled at multiple levels, including regulation of its subcellular localization; the mechanisms underlying the targeting of dynein to various sites within cells, however, are not well understood. Our current model is that asun coordinates spermatogenesis by promoting dynein recruitment to the nuclear surface, a critical step that is required for nucleus-centrosome coupling at M-phase entry and fidelity of meiotic divisions. ASUN exhibits a dynamic localization pattern during Drosophila male meiosis, and the timing of its release from the nucleus to the cytoplasm correlates with the appearance of dynein on the nuclear surface in G2 spermatocytes. We will assess whether this regulated movement of ASUN within spermatocytes is critical for controlling the activity of dynein. We propose experiments that will allow us to gain a more detailed understanding of the mechanism by which dynein is recruited to the nuclear surface with a focus on elucidating the role of ASUN in this process. Our preliminary data suggest that dynein anchored on the nuclear surface of spermatocytes may preferentially bind to microtubules that are post-translationally modified by acetylation. We will test our hypothesis that this pool of acetylated microtubules mediates key events of Drosophila male meiosis, including nucleus-centrosome coupling. The proposed experiments have the potential to illuminate the mechanism of action of ASUN, to identify additional factors required for recruitment of the dynein motor complex to the nuclear surface, and to define the role of microtubule acetylation during spermatogenesis. PUBLIC HEALTH RELEVANCE: The mechanisms controlling localization of dynein motors within cells are not well understood. We have shown that ASUN is required for recruitment of dynein to the nuclear surface of Drosophila spermatocytes, a critical event for fidelity of meiotic divisions. Because the vertebrate homolog of ASUN also controls dynein localization in cultured human cells during mitosis, elucidation of the mechanism of action of ASUN may have important implications for human diseases such as cancer.

描述（由申请人提供）：涉及细胞周期的基因的高度功能保护与果蝇果蝇的超级遗传学和细胞学相结合，使其成为在发育环境中研究细胞周期调节的理想模型生物。精子发生利用了与生长和分化程序协调的有丝分裂和减数分裂细胞周期来产生功能性精子。通过突变分析，我们将编码进化保守蛋白的ASUND（ASUN）确定为果蝇精子发生的必要调节剂。在减数分裂的预言期间，Asun精子细胞停滞。令人惊讶的是，被捕的精子细胞包含自由的中心体，无法与细胞核稳定相关。克服逮捕的精子细胞在减数分裂纺锤体组件，染色体分离和细胞因子中表现出严重的缺陷。此外，中心衍生的基体从ASUN症状后精子中脱离了细胞核，导致精子发生后期异常。我们发现，ASUN精子细胞和精子表现出核周动力蛋白的急剧降低。 Dynein是一种减去最终导向的微管运动络合物，是不同生物学过程所需的，从细胞内货物到细胞迁移。动力蛋白在多个层面上受到控制，包括调节其亚细胞定位。但是，尚不清楚动力蛋白靶向细胞中各个位点的基础机制。我们当前的模型是，ASUN通过促进动力蛋白募集到核表面来协调精子发生，这是核中核体偶联的关键步骤，在M期进入和减数分裂分裂的忠诚度时耦合。 Asun在果蝇男性减数分裂过程中表现出动态定位模式，其从细胞核到细胞质的释放时间与G2精子细胞中核表面上的动力蛋白的出现相关。我们将评估ASUN在精子细胞中的这种调节运动对于控制动力蛋白的活性至关重要。我们提出的实验将使我们能够更详细地了解将动力蛋白招募到核表面的机制，重点是阐明ASUN在此过程中的作用。我们的初步数据表明，锚定在精子细胞的核表面上的动力蛋白可能优先与乙酰化后翻译后修饰的微管结合。我们将测试我们的假设，即这种乙酰化的微管池介导果蝇男性减数分裂的关键事件，包括核中心体偶联。提出的实验有可能照亮ASUN的作用机理，以确定将动力蛋白运动复合物募集到核表面所需的其他因素，并确定精子发生过程中微管乙酰化的作用。公共卫生相关性：控制动力蛋白电动机在细胞中定位的机制尚不清楚。我们已经表明，ASUN是将动力蛋白募集到果蝇精子细胞的核表面所必需的，这是减数分裂分裂的关键事件。由于ASUN的脊椎动物同源物在有丝分裂过程中还控制着培养的人类细胞中的动力蛋白定位，因此阐明ASUN作用机理可能对癌症等人类疾病具有重要意义。