Elucidating the role of mai1 in cell cycle control and DNA damage response

描述（由申请人提供）：细胞通过激活导致细胞周期阻滞、DNA修复和凋亡的信号转导途径对DNA损伤做出反应。DNA损伤检查点对于维持基因组完整性至关重要。DNA损伤反应在人类病理，特别是癌症中的重要性已经得到了充分的证实。编码DNA损伤检查点蛋白的各种基因的突变与各种人类疾病综合征有关，这些疾病综合征通常以增加患癌症的易感性为特征。尽管对DNA损伤检查点的理解已经取得了重大进展，但构成DNA损伤反应的途径网络是复杂的，其他成分仍有待确定。我们已经筛选突变斑马鱼胚胎的DNA损伤反应缺陷。这确定了两个突变系在暴露于电离辐射后无法阻止有丝分裂进入。这些细胞系中的每一个都携带一个突变基因，我们将其命名为mail（辐照后有丝分裂）。在包括人类在内的其他脊椎动物中，mail基因编码一种具有同源物的蛋白质。有氨基酸块在这些物种中是高度保守的，但没有基序或结构域表明潜在的生物学功能。除了检查点表型外，未辐照的斑马鱼在正常细胞周期进程中也有缺陷。这项提议的目标是确定Mail在细胞周期调节和DNA损伤检查点中的作用。具体目的有两个：(1)研究斑马鱼突变体的DNA损伤检查点和细胞周期缺陷；(2)建立Mail在人体细胞中的功能。

DESCRIPTION (provided by applicant): Cells respond to DNA damage by activating signal transduction pathways that lead to cell cycle arrest, DNA repair and apoptosis. DNA damage checkpoints are essential for the maintenance of genomic integrity. The importance of the DNA damage response in human pathology, especially cancer, is well established. Mutations in various genes encoding DNA damage checkpoint proteins are associated with a variety of human disease syndromes and these are often characterized by an increased predisposition to cancer. Although significant progress has been made understanding DNA damage checkpoints, the network of pathways that compose the DNA damage response is complex and additional components remain to be identified. We have screened mutant zebrafish embryos for DNA damage response defects. This identified two mutant lines that fail to arrest mitotic entry following exposure to ionizing radiation. Each of these lines carries a mutation in a gene that we have named mail (mitosis after irradiation 1). The mail gene encodes a protein with orthologues in other vertebrate species, including humans. There are blocks of amino acids that are highly conserved across these species, but no motifs or domains to suggest a potential biological function. In addition to a checkpoint phenotype, unirradiated mail zebrafish have a defect in normal cell cycle progression. The goal of this proposal is to determine Mail's role in cell cycle regulation and DNA damage checkpoints. There are two specific aims: (1) to investigate the DNA damage checkpoint and cell cycle defects of mail zebrafish mutants; and (2) to establish the function of Mail in human cells.