Developmental control of cell cycle exit

细胞周期退出的发育控制

• 批准号: 7037774
• 负责人: Bruce Alexander Edgar
• 金额: $ 26.82万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7037774
• 关键词: Drosophilidae; cell cycle; cell differentiation; cyclins; developmental genetics; eye development; flow cytometry; gene expression; gene induction /repression; genetic regulatory element; genetic screening; immunofluorescence technique; in situ hybridization; invertebrate embryology; protein structure; regulatory gene; site directed mutagenesis; transcription factor; transcription termination

DESCRIPTION (provided by applicant): An unsolved mystery of development concerns how growth and form are controlled. The regulation of cell proliferation is central to this problem, and the mechanisms controlling cell cycle arrest upon cell differentiation are particularly relevant. Cell cycle exit is also critical in carcinogenesis, where it is bypassed, and in wound healing and regeneration, where it is reversed to allow renewed proliferation. While cell cycle exit has been studied in cell culture and in vivo in several model organisms, the mechanisms that couple differentiation signals to the cell cycle control apparatus remain poorly understood. No general paradigm exists explaining the ubiquitous coupling of cell differentiation to G1 arrest. This proposal is to study cell cycle exit at differentiation in Drosophila in three well-characterized contexts: the embryo, the wing, and the eye. We will test the hypothesis that differentiation signals dominantly suppress the transcription of cell cycle control genes via an E2F/RB-independent mechanism. In Aim 1, we manipulate the activity of known cell cycle control genes to define the mechanism that triggers cell cycle exit, and we also analyze changes in gene expression during the exit process. In Aim 2, we study the transcriptional regulatory region of the critical cell cycle control gene, cyclin E, to identify cis-acting elements, and eventually trans-acting factors, that mediate its silencing at differentiation. In Aim 3 we perform genetic screens in the fly to identify novel genes that are functionally important for cell cycle exit. The combined results should distinguish between the many plausible explanations of cell cycle exit suggested in the literature, identify new gene products that mediate cell cycle exit, and provide a working paradigm for future studies of how differentiation signals interface with the cell cycle control apparatus. Because the genetic networks that orchestrate tissue patterning, cell differentiation, and cell cycle control are conserved between Drosophila and man, the results obtained herein should inform ongoing studies of human development and disease.

描述(申请人提供)：一个尚未解开的发展之谜，涉及如何控制生长和形态。细胞增殖的调控是这个问题的核心，而控制细胞分化时细胞周期停滞的机制尤其相关。细胞周期退出在癌变中也是至关重要的，在癌症发生中它被绕过，在伤口愈合和再生中它被逆转以允许新的增殖。虽然细胞周期退出在细胞培养和体内的几种模式生物中已经被研究，但将分化信号耦合到细胞周期调控装置的机制仍然知之甚少。目前还没有通用的范例来解释细胞分化与G1期停滞之间的普遍耦合。这项建议是要研究果蝇在分化时的细胞周期退出，在三个特征很好的环境中：胚胎、翅膀和眼睛。我们将检验这一假设，即分化信号主要通过E2F/Rb非依赖的机制抑制细胞周期控制基因的转录。在目标1中，我们操纵已知的细胞周期调控基因的活性，以确定触发细胞周期退出的机制，并分析退出过程中基因表达的变化。在目标2中，我们研究了关键的细胞周期控制基因Cyclin E的转录调控区域，以确定在分化过程中介导其沉默的顺式作用元件，以及最终的反式作用因子。在目标3中，我们在果蝇中进行遗传筛选，以确定对细胞周期退出具有重要功能的新基因。综合的结果应该区别于文献中提出的许多关于细胞周期退出的合理解释，识别介导细胞周期退出的新的基因产物，并为未来研究分化信号如何与细胞周期调控装置交互作用提供一个工作范式。由于协调组织模式、细胞分化和细胞周期控制的遗传网络在果蝇和人类之间是保守的，因此这里获得的结果应该会为正在进行的人类发育和疾病研究提供信息。