EXPRESSION OF GENETIC VARIATION IN CULTURED CELLS

本研究的基本目标是确定 额外突变事件，如有丝分裂重组，基因失活， 染色体重排、缺失或染色体分离， 隐性突变在培养的哺乳动物细胞中的表达。 我们 最终目标是清楚地了解细胞过程， 遗传变异的产生和表达机制 在哺乳动物体细胞中的作用，以及这些过程在 癌发生的起始和促进阶段。 集古典 体细胞遗传学方法与重组DNA技术，我们将 研究染色体重排对基因表达的影响， 突变或缺失。 我们将利用DNA介导的基因转移来研究 基因的表达和突变性如何受其染色体的影响 环境，并确定是否转移中国仓鼠APRT基因， 序列与内源性CHO APRT基因的易感性不同， 突变、失活或缺失。 此外，我们建议利用 对于四种不同的连锁遗传或基因突变是杂合的细胞系， 细胞遗传学标记以测定有丝分裂重组，基因失活， 染色体重排、缺失或染色体分离事件 导致APRT-隐性突变表型在 诱变剂处理或未处理的对照细胞培养物。 我们将使用这个 确定额外突变事件是否由已知的 肿瘤引发剂或促进剂。 这些实验应该提供 有关参与的细胞过程和机制的信息 肿瘤的发生和发展。

The basic objective of this research is to determine the roles of extra-mutational events, such as mitotic recombination, gene inactivation, chromosomal rearrangements, deletions, or chromosome segregation, in the expression of recessive mutations in cultured mammalian cells. Our ultimate goal is a clear understanding of the cellular processes and mechanisms involved in the generation and expression of heritable variation in mammalian somatic cells, and definition of the role of such processes in the initiation and promotion stages of carcinogenesis. Combining classical somatic cell genetic approaches with recombinant DNA technologies, we will study the effects of chromosomal rearrangements on gene expression and mutation or deletion. We will utilize DNA-mediated gene transfer to study how the expression and mutability of a gene are affected by its chromosomal environment, and to determine whether transferred Chinese hamster APRT gene sequences differ from the endogenous CHO APRT genes in their susceptibility to mutation, inactivation, or deletion. In addition, we propose to utilize a cell line that is heterozygous for four different linked genetic or cytogenetic markers to assay mitotic recombination, gene inactivation, chromosomal rearrangements, deletions, or chromosome segregation events leading to the expression of APRT- recessive mutant phenotypes in mutagen-treated or untreated control cell cultures. We will use this system to determine whether extra-mutational events are induced by known tumor initiators or promoters. These experiments should provide information concerning the cellular processes and mechanisms involved in tumor initiation and promotion.