CHARACTERIZATION OF A MAMMALIAN REPAIR GENE

描述：虽然已知正常哺乳动物细胞使用诱变剂 复制旁路作为对某些DNA损伤的耐受机制 关于DNA修复/损伤耐受的这一途径仍有待了解 分子水平。一种名为CHO-UV1的CHO突变体，显示出缺陷突变 旁路修复已隔离。UV1对各种病毒的杀戮高度敏感 DNA损伤剂包括烷基化药物、丝裂霉素C和紫外线，但不包括 电离辐射。UV1具有正常的核苷酸切除修复，但存在缺陷 在旁路修复和复制后恢复(PRR)中。它的易变性不如 野生型CHO意味着正常的UV1“基因”功能是诱变的。这个 通过将人类基因组DNA导入UV1可补充UV1的表型 或者通过将UV1与正常的人类细胞融合，表明人类细胞拥有 相当于在UV1中突变的基因。编码人截短基因的全长cDNA 已发现一种形式的Aly转录辅助激活因子可以补充 MMC杀伤UV1的超敏反应。反义词--另一方面， 增加CHO对MMC的敏感性。一种完全耐MMC的人类-UV1杂交种 被发现含有人类染色体11P的一段带有Aly基因的片段 它。因此，初步证据表明阿里是UV1的候选人 “基因”和Aly在旁路修复和PRR中的作用。 研究建议：(1)详细研究Aly在UV1中的作用 PRR修复途径，(2)检查另一个基因可以 补充UV1-PRR途径并进一步鉴定其表型 突变体，以及(3)检测Aly(和/或其他互补的)的生化作用 基因)在致突变的PRR过程中。

DESCRIPTION:Although it is known that normal mammalian cells employ mutagenic replicative bypass as a tolerance mechanism for certain DNA lesions, much remains to be learned about this pathway of DNA repair/damage tolerance at the molecular level. A CHO mutant, called CHO-UV1, showing defective mutagenic bypass repair has been isolated. UV1 is hypersensitive to killing by various DNA damaging agents including alkylating drugs, mitomycin C and UV, but not ionizing radiation. UV1 has normal nucleotide excision repair but is defective in bypass repair and post replication recovery (PRR). It is less mutable than wild type CHO implying that the normal UV1 "gene" function is mutagenic. The phenotype of UV1 can be complemented by transfecting human genomic DNA into UV1 or by fusing UV1 with normal human cells, suggesting that human cells possess an equivalent of the gene mutated in UV1. A human cDNA encoding a truncated form of the ALY transcriptional coactivator has been found to complement the MMC killing hypersensitivity of UV1. Antisense-ALY, on the other hand, increases CHO's sensitivity to MMC. A fully MMC-resistant human-UV1 hybrid has been found to contain a fragment of human chromosome 11p with the ALY gene in it. The preliminary evidence thus implicates ALY as a candidate for the UV1 "gene" and a role for ALY in bypass repair and PRR. Studies are proposed to: (1) Investigate in detail the role of ALY in the UV1 PRR repair pathway, (2) examine the possibility that another gene can complement the UV1-PRR pathway and further characterize the phenotype of the mutant, and (3) examine the biochemical role of ALY (and/or other complementing genes) in the mutagenic PRR process.