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， 复制旁路作为某些DNA损伤的耐受机制， 关于这种DNA修复/损伤耐受的途径， 分子水平。一种CHO突变体，称为CHO-UV 1，显示有缺陷的诱变性， 旁路修复已被隔离UV 1对各种杀伤敏感， DNA损伤剂包括烷化剂、丝裂霉素C和UV，但不包括 电离辐射UV 1具有正常的核苷酸切除修复，但有缺陷 在旁路修复和复制后恢复（PRR）中。它的可变性小于 野生型CHO意味着正常的UV 1“基因”功能是致突变的。的 UV 1的表型可以通过将人基因组DNA转染到UV 1中来补充 或者通过将UV 1与正常人体细胞融合，这表明人体细胞具有 相当于紫外线1突变的基因编码截短的 已经发现ALY转录辅激活因子的形式与 MMC对UV 1超敏反应的抑制作用。另一方面，反义ALY， 增加CHO对MMC的敏感性。一个完全抗MMC的人-UV 1杂交体 发现含有人类染色体11 p的片段，其中ALY基因在 因此，初步证据表明，ALY是UV的候选人1。 “基因”以及ALY在旁路修复和PRR中的作用。 本文拟从以下几个方面进行研究：（1）详细研究ALY在紫外线中的作用 PRR修复途径，（2）检查另一个基因可以 补充UV 1-PRR途径，并进一步表征 突变体，和（3）检查ALY（和/或其他互补基因）的生物化学作用 基因）在诱变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.