A Screen for DNA Damage Checkpoint Mutants in Zebrafish

描述(申请人提供)：癌细胞是通过体细胞中积累的DNA突变而产生的，在体细胞中，细胞DNA不断受到外源物质和细胞代谢物的攻击。正常细胞有监测基因组DNA完整性和修复DNA突变的机制，而癌细胞经常失去对DNA损伤做出有效反应的能力，从而促进突变的积累，导致不受调控的生长。细胞对DNA损伤的一个关键反应是阻止细胞周期，从而为DNA复制或有丝分裂之前的修复提供时间。DNA损伤诱导细胞周期停滞的机制复杂，信号转导途径的许多组成部分尚不清楚。斑马鱼作为脊椎动物模型在发现DNA损伤反应基因方面具有相当大的优势。通过对霍普金斯插入突变体库中斑马鱼胚胎的筛选，鉴定出两个隐性胚胎致命突变，它们可以消除DNA损伤诱导的细胞周期停滞。受这些突变影响的基因已经被克隆，它们与人类同源基因具有很高的相似性，但人们对它们的功能知之甚少。这些基因在人类细胞DNA损伤检查点的功能将被检测。此外，霍普金斯大学的突变体库将对额外的DNA损伤检查点故障突变进行筛选。

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.