MECHANISMS OF CHEMICAL MUTAGENESIS IN MAMMALIAN CELLS

本研究项目的目的是阐明 DNA前体水平和哺乳动物细胞中的诱变之间的关系。 我们 以前的结果表明，脱氧核苷酸池水平的扰动 5-溴脱氧尿苷（BrdU）在诱导中起关键作用 姐妹染色单体交换（SCE）。 我们计划采取几个 研究DNA前体水平对诱变作用的方法， BrdU和其他诱变剂。 这些方法包括：1）隔离 脱氧核苷酸代谢改变的中国仓鼠细胞突变体 并确定突变改变对 突变和SCE频率; 2）确定是否具有内在 核苷酸代谢的差异（人B和T淋巴母细胞） 自发突变频率和诱变剂敏感性的差异; 3)确定脱氧核苷酸池的改变是否涉及 几种人类染色体断裂综合征的表达; 4）研究 脱氧核苷酸库不平衡对DNA合成速率的影响 DNA前体通道在诱变中的作用; 5）鉴定实际的 脱氧核苷酸池失衡影响DNA碱基变化 诱变;和6）检查DNA甲基化和错配修复的作用 在哺乳动物细胞诱变中。 这些研究应该能让我们确定 DNA前体水平与诱变之间的关系。 这 信息可能导致预测有关的易感性， 特定细胞类型的突变和可能的恶性转化， 基于细胞的脱氧核苷酸代谢。

The objective of this research program is to elucidate the relationship between DNA precursor levels and mutagenesis in mammalian cells. Our previous results suggested that perturbation of deoxynucleotide pool levels by the mutagen 5-bromodeoxyuridine (BrdU) plays a key role in the induction of mutation and sister chromatid exchange (SCE). We plan to take several approaches to study the role that DNA precursor levels play mutagenesis by BrdU and other mutagens. These approaches will include: 1) isolate Chinese hamster cell mutants with alterations in deoxynucleotide metabolism and determine the effect that the mutational alterations have on frequencies of mutation and SCE; 2) determine whether cells with intrinsic differences in nucleotide metabolism (human B and T lymphoblasts) have differences in spontaneous mutation frequencies and mutagen sensitivities; 3) determine whether deoxynucleotide pool alterations are involved in the expression of several human chromosomal breakage syndromes; 4) study the effect of deoxynucleotide pool imbalance on rates of DNA synthesis and the role of channeling of DNA precursors in mutagenesis; 5) identify the actual DNA base changes when deoxynucleotide pool imbalances influence mutagenesis; and 6) examine the role of DNA methylation and mismatch repair in mammalian cell mutagenesis. These studies should enable us to determine the relationship between DNA precursor levels and mutagenesis. This information may lead to predictions concerning the susceptibility of a particular cell type to mutagenesis and possibly malignant transformation, based on that cell's deoxynucleotide metabolism.