GENETIC CONTROL OF CELL CYCLE ARREST AFTER DNA DAMAGE

在真核生物中，如果染色体受损，细胞周期就会停滞在G2期， 就在有丝分裂和染色体分离之前。基因组稳定性和 真核细胞的生存需要控制以确保有丝分裂不会 一直持续到染色体完好。DNA损伤后在G2被捕 受基因控制。我研究的长期目标是 了解细胞如何检测DNA损伤并发出细胞停滞的信号 周而复始。在酿酒酵母中，G2的停滞机制需要 一种负调控基因，RAD9基因。遗传途径的控制 G2中的停滞是复杂的；存在停滞缺陷的突变的遗传分析 在G2中，有6个基因对这种调控是必不可少的。我的 研究的重点是确定这6个基因如何进入有丝分裂 检查点，控制DNA损伤后的细胞周期停滞。 将分离MEC基因，并确定其DNA序列以查看它 它们编码已知的生化或结构功能的蛋白质。(DNA 两个MEC基因的测序已经完成)。的遗传控制 MEC基因的有丝分裂可能是复杂的，涉及到过程的调节 除了在DNA损伤后在G2中被阻止外，还将检查mec突变 在从G2到有丝分裂的转变中发挥结构性作用，用于控制 DNA修复，以及调节细胞其他阶段的停滞 除G2外，还可循环。利用分离的MEC基因获得两个基因 方法将检查上位性和基因的物理相互作用 产品；对MEC遗传途径的层次结构的描述将 浮出水面。将使用一种新的基因来确定其他MEC基因座 选择，重点放在可能对有丝分裂和 MEC依赖控制的目标。最后，三个已知基因的作用 为了成为必要的，或为了调节，有丝分裂将进行基因测试，以确定 作为MEC依赖的负性控制的可能靶点或中介的作用 (包括CDC28、MIH1和Wee1)。

In eucaryotes if chromosomes are damaged, the cell cycle arrests in G2, just before mitosis and chromosome segregation. Genomic stability and viability of eucaryotes requires controls that ensure mitosis does not occur until chromosomes are intact. Arrest in G2 after DNA damage is genetically regulated. The long-term objective of my research is to understand how the cell detects DNA damage and signals arrest of the cell cycle. In Saccharomyces cerevisiae, the mechanism of arrest in G2 requires a negative regulator, the RAD9 gene. The genetic pathway controlling arrest in G2 is complex; genetic analysis of mutants defective for arrest in G2 show that 6 genes are essential for this regulatory control. My research focuses on determining how the 6 genes for mitosis-entry checkpoint, control cell cycle arrest after DNA damage. The MEC genes will be isolated and their DNA sequences determined to see it they encode proteins of known biochemical or structural function. (DNA sequence for two MEC genes has been completed). Genetic controls of mitosis by the MEC genes may be complex and involve regulation of precesses in addition to arrest in G2 after DNA damage; mec mutants will be examined for a constitutive role in the transition from G2 to mitosis, for control of DNA repair, and for regulation of arrest in other phases of the cell cycle in addition to G2. Using the isolated MEC genes two genetic approaches will examine epistasis and physical interactions of gene products; a description of hierarchy of the MEC genetic pathway will emerge. Additional MEC loci will be identified using a new genetic selection, with a focus on genes that may be essential for mitosis and the target of MEC-dependent control. Finally, the roles of three genes known to be essential, or to regulate, mitosis will be tested genetically for roles as possible targets or mediators of MEC-dependent negative control (including CDC28, MIH1, and wee1).