REGULATION OF ARGININOSUCCINATE SYNTHETASE

这个项目的目标是分析基因调控对 精氨酸琥珀酸合成酶(AS)基因座。其目的是确定 精氨酸和酶调节代谢物的分子基础 刀豆素抗性(CANR)细胞中的过量生产。它的作用机制 CARR细胞中酶的过度产生可能与高脂血症的机制有关 在肝脏中的器官特异性表达。AS基因的结构分析和 多个假基因进展顺利，将完成。尝试次数为 利用DNA介导的基因转移获得AS表达的研究进展 通过cDNA克隆和微基因构建。CANR杂合型变异体 瓜氨酸血症细胞株将被用来区分是否可以 表型为顺式或反式。一种主要的分析方法 监管将利用DNA介导的基因转移试图 演示(1)转染型DNA对代谢产物的调节和(2)改变 与CANR表型相关的调节与 与受体细胞或转染体DNA结合。的功能区域 将使用缺失突变体和连接物来鉴定导入的DNA 扫描变种人。旨在克隆调控基因的实验也是 建议。提议的实验直接与理解 哺乳动物细胞中基因表达的调控。这仍然是一个很高的 优先致力于生物医学研究。对这一人类基因座的分析 与瓜氨酸血症直接相关，而调节突变体可能 除了众所周知的结构突变外，还存在。

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.