Ohtake A, Takiguchi M, Shigeto Y, Amaya Y, Kawamoto S, Mori M
Institute for Medical Genetics, Kumamoto University Medical School, Japan.
J Biol Chem. 1988 Feb 15;263(5):2245-9.
Liver-type arginase (EC 3.5.3.1) catalyzes the last step of urea synthesis and is expressed specifically in the liver of ureotelic animals. Expression of liver arginase is developmentally and hormonally regulated in coordination with other urea cycle enzymes. The gene for the rat enzyme was cloned and the structure determined. This gene is 12 kilobases long and is split into eight exons. All of the splice donor and acceptor sites conform to the GT/AG rule. The transcription initiation site was determined by nuclease S1 mapping and primer extension. A "TATA box"-like sequence and a "CAAT box"-like sequence are present 27 and 60 bases upstream from the cap site, respectively. Upstream and downstream from the cap site, there are several sets of direct repeats and inverted repeats and several sequences resembling the transcription factor Sp1 binding sites, the enhancer core sequences, the glucocorticoid receptor binding sites, the 12-O-tetradecanoylphorbol-13-acetate responsive elements, and the putative elements for liver-specific expression of albumin genes. A 15-nucleotide sequence in the 5'-flanking region of the arginase gene is highly homologous with sequences in the 5'-flanking regions of the genes for rat ornithine carbamoyltransferase (EC 2.1.3.3) and for human argininosuccinate synthetase (EC 6.3.4.5), other two enzymes of the urea cycle.
肝型精氨酸酶（EC 3.5.3.1）催化尿素合成的最后一步，在排尿素动物的肝脏中特异性表达。肝脏精氨酸酶的表达在发育和激素水平上与其他尿素循环酶协同调节。大鼠该酶的基因已被克隆并确定了结构。该基因长12千碱基，被分成八个外显子。所有的剪接供体和受体位点均符合GT/AG规则。通过核酸酶S1作图和引物延伸确定了转录起始位点。在帽位点上游27和60个碱基处分别存在一个类似“TATA盒”的序列和一个类似“CAAT盒”的序列。在帽位点的上游和下游，有几组直接重复和反向重复序列，以及几个类似于转录因子Sp1结合位点、增强子核心序列、糖皮质激素受体结合位点、12-O-十四烷酰佛波醇-13-乙酸酯反应元件和白蛋白基因肝脏特异性表达的假定元件的序列。精氨酸酶基因5'-侧翼区的一个15核苷酸序列与大鼠鸟氨酸氨甲酰转移酶（EC 2.1.3.3）和人精氨琥珀酸合成酶（EC 6.3.4.5）基因5'-侧翼区的序列高度同源，这两种酶是尿素循环中的另外两种酶。
