Regulation of the endo cell cycle in Drosophila

描述（由申请人提供）：在所有细胞中，精确调节DNA复制是必不可少的，因为这方面的失败会导致癌症或发育缺陷。大多数动物和植物都有多倍体或多线细胞，这是DNA复制调节改变的结果，产生的细胞可以作为代谢工厂或大型支持细胞。此外，一些生物体过度复制或复制不足的特定基因组区域来控制基因表达。DNA复制调控的这些发育方面是本研究的重点。基因组学和细胞生物学的方法将被用来了解后生动物DNA复制是如何控制在发展过程中，这一生物学问题的创新方法。通过基因组微阵列方法，在果蝇Drosophila melanogaster中发现了扩增和复制不足基因的新例子。这些差异复制基因的复制特性和生物学功能将被破译。微阵列的方法将被用来确定如何广泛使用的差异复制作为果蝇基因表达的发展策略。DNA复制的启动由一组从酵母到人类保守的蛋白质控制，并且在果蝇中开发了一个模型系统，可以分析这些蛋白质和复制起点。可以在卵泡细胞中直接观察到起源识别复合物（ORC）、Cdt 1/DUP起始蛋白和MCM六聚体的结合。此外，在复制起始后，可以看到DUP和MCM蛋白在延伸期间与复制叉一起移动。这种细胞生物学方法，结合恢复突变体和检查它们在复制中的缺陷的能力，提供了一种强有力的手段来描绘复制起始的调节电路。DUP蛋白及其抑制剂Geminin的作用将在产生多倍体或多线细胞的细胞周期中定义。在最后的目标，抑制有丝分裂，允许形成多倍体或多线染色体的机制将被描绘出来，它将被确定如何保护增殖细胞成为多倍体。

DESCRIPTION (provided by applicant): It is essential in all cells to regulate DNA replication precisely, as failures in this lead to cancer or developmental defects. Most, if not all, animals and plants have polyploid or polytene cells, the consequence of altered regulation of DNA replication to produce cells that can function as metabolic factories or serve as large support cells. In addition, some organisms over or underreplicate specific genomic regions to control gene expression. These developmental aspects of the regulation of DNA replication are the focus of this research. The approaches of genomics and cell biology will be used to understand how metazoan DNA replication is controlled during development, innovative methodologies for this biological problem. New examples of amplified and underreplicated genes have been identified in the fruit fly Drosophila melanogaster by a genomic microarray approach. The replicative properties and biological functions of these differentially replicated genes will be deciphered. The microarray methodology will be employed to determine how widely used differential replication is as a developmental strategy for gene expression in Drosophila. Initiation of DNA replication is controlled by a set of proteins conserved from yeast to humans, and a model system has been developed in Drosophila that permits analysis of these proteins and replication origins. Binding of the Origin Recognition Complex (ORC), the Cdtl/DUP initiator protein, and the MCM hexamer can be visualized directly in the ovarian follicle cells. Furthermore after replication initiation, the DUP and MCM) proteins can be seen moving with replication forks during elongation. This cell biological approach, combined with the ability to recover mutants and examine their defects in replication, provides a powerful means to delineate the regulatory circuitry for replication initiation. The role of the DUP protein and its inhibitor Geminin will be defined in cell cycles that produce polyploid or polytene cells. In the final aim, the mechanisms that inhibit mitosis to permit formation of polyploid or polytene chromosomes will be delineated, and it will be determined how proliferating cells are protected from becoming polyploid.