A Screen for DNA Damage Checkpoint Mutants in Zebrafish

描述（由申请人提供）：癌细胞是通过体细胞中累积的DNA突变产生的，其中细胞DNA不断受到外源性试剂和细胞代谢物的攻击。正常细胞具有监测基因组DNA完整性和修复DNA突变的机制，而癌细胞经常失去有效应对DNA损伤的能力，从而促进突变的积累，导致生长失调。对DNA损伤的关键细胞反应是细胞周期的停滞，从而在DNA复制或有丝分裂之前提供修复的时间。DNA损伤诱导细胞周期停滞的机制很复杂，信号传导途径的许多组成部分尚不清楚。斑马鱼作为发现DNA损伤反应基因的脊椎动物模型具有相当大的优势。通过在霍普金斯的插入突变体收集中筛选斑马鱼胚胎，鉴定出两种隐性胚胎致死突变，其消除了DNA损伤诱导的细胞周期停滞。受这些突变影响的基因已被克隆，它们具有高度相似性的人类同源物，但对其功能知之甚少。这些基因在人类细胞DNA损伤检查点中的功能将被检查。此外，霍普金斯的突变体收集将筛选额外的DNA损伤检查点失败突变体。

DESCRIPTION (provided by applicant): Cancer cells are created through accumulated DNA mutations in somatic cells, where cellular DNA is constantly assaulted by exogenous agents and cellular metabolites. Normal cells have mechanisms for monitoring genomic DNA integrity and repairing the DNA mutations, while cancer cells frequently lose the ability to efficiently respond to DNA damage, facilitating the accumulation of mutations that lead to deregulated growth. A critical cellular response to DNA damage is the arrest of the cell cycle, thereby providing time for repair before DNA replication or mitosis. The mechanisms of DNA damage-induced cell cycle arrest are complex, and many components of the signal transduction pathway are unknown. The zebrafish has considerable advantages as a vertebrate model for the discovery of DNA damage response genes. By screening zebrafish embryos in the Hopkins' insertional mutant collection, two recessive embryonic lethal mutations were identified that abrogate DNA damage-induced cell cycle arrest. The genes affected by these mutations have been cloned, and they have human homologues with high similarity, but little is known about their functions. The function of these genes in the DNA damage checkpoints of human cells will be examined. Also, the Hopkins' mutant collection will be screened for additional DNA damage checkpoint failure mutants.