REGULATION OF ARGININOSUCCINATE SYNTHETASE

该项目的目的是分析基因调控， 乙酰氨基琥珀酸合成酶（AS）基因座。 目的是确定 精氨酸调节代谢物和酶的分子基础 在刀豆氨酸抗性（Canr）细胞中过量生产。 的机理 Canr细胞中的酶过量产生可能与高表达的机制有关。 肝脏中的器官特异性表达。 AS基因的结构分析， 多个假基因的研究进展顺利，即将完成。 尝试 利用DNA介导的基因转移获得AS表达的进展 用cDNA克隆和小基因构建。 杂合子的Canr变体 瓜氨酸血症细胞系将被用来区分癌症是否是一种恶性肿瘤， 表型是顺式或反式作用的。 分析的主要方法 调控将是使用DNA介导的基因转移， 证明（1）用转染的DNA调节代谢物和（2）改变 与Canr表型相关的调节， 受体细胞或转染的DNA。 功能区 转染的DNA将使用缺失突变体和接头进行鉴定 扫描变种人 设计克隆调控基因的实验也 提出了 所提出的实验直接关系到理解 哺乳动物细胞中基因表达的调节。 这仍然是一个高 生物医学研究的优先奋进。 对这个人类基因座的分析 与瓜氨酸血症疾病直接相关，调节突变体可能 除了已知的结构突变体之外，还存在其他突变体。

The objective of this project is to analyze gene regulation for the argininosuccinate synthetase (AS) locus. The intent is to determine the molecular basis for metabolite regulation by arginine and for enzyme overproduction in canavanine-resistant (Canr) cells. The mechanism of enzyme overproduction in Canr cells may be related to the mechanism of high organ specific expression in liver. Structural analysis of the AS gene and multiple pseudogenes is well advanced and will be completed. Attempts are in progress to obtain expression of AS using DNA mediated gene transfer with cDNA clones and minigene constructions. Canr variants of heterozygous citrullinemia cell lines will be used to distinguish whethe the Canr phenotype is cis- or trans-acting. The primary method for analysis of regulation will be the use of DNA mediated gene transfer attempting to demonstrate (1) metabolite regulation with transfected DNA and (2) altered regulation associated with the Canr phenotype either related to the recipient cells or to the transfected DNA. Functional regions of transfected DNA will be identified using deletion mutants and linker scanning mutants. Experiments designed to clone regulatory genes are also proposed. The proposed experiments are directly relevant to understanding regulation of gene expression in mammalian cells. This remains a high priority endeavor in biomedical research. Analysis of this human locus has direct relevance to the disease citrullinemia, and regulatory mutants may exist in addition to the well known structural mutants.