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

描述(申请人提供)：细胞通过激活信号转导通路来应对DNA损伤，这些信号转导通路导致细胞周期停滞、DNA修复和细胞凋亡。DNA损伤检查点对于维持基因组的完整性是必不可少的。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，这些综合征通常以癌症易感性增加为特征。尽管对DNA损伤检查点的了解已经取得了重大进展，但构成DNA损伤反应的通路网络是复杂的，更多的成分仍有待确定。我们已经对突变的斑马鱼胚胎进行了DNA损伤反应缺陷的筛选。这发现了两个突变株系，它们在暴露于电离辐射后未能阻止有丝分裂进入。这些菌株中的每一株都携带一种我们称之为mail(辐射后有丝分裂1)的基因突变。Mail基因编码一种蛋白质，与包括人类在内的其他脊椎动物物种中的同源基因。有一些氨基酸在这些物种中高度保守，但没有基序或结构域来暗示潜在的生物功能。除了检查点表型外，未经辐照的斑马鱼在正常的细胞周期进程中也存在缺陷。这项提案的目标是确定Mail在细胞周期调节和DNA损伤检查点中的作用。有两个特定的目的：(1)研究邮件斑马鱼突变体的DNA损伤检查点和细胞周期缺陷；(2)建立MAIL在人类细胞中的功能。

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.