Pérez-Amador M A, Carbonell J, Granell A
Departamento de Biología del Desarrollo de Plantas, Instituto de Biología Molecular y Celular de Plantas, UPVA-CSIC, Valencia, Spain.
Plant Mol Biol. 1995 Sep;28(6):997-1009. doi: 10.1007/BF00032662.
A cDNA coding for arginine decarboxylase (ADC, EC 4.1.1.19) has been isolated from a cDNA library of parthenocarpic young fruits of Pisum sativum (L.). The deduced aminoacid sequence is 74%, 46% and 35% identical to ADCs from tomato, oat and Escherichia coli, respectively. When the pea ADC cDNA was put under the control of the galactose inducible yeast promoter CYC1-GAL10 and introduced into Saccharomyces cerevisiae, it conferred galactose-regulated expression of the ADC activity. The ADC activity expressed in S. cerevisiae was inhibited 99% by alpha-DL-difluoromethylarginine (DFMA), a specific inhibitor of ADC activity. No activity was detected in the untransformed S. cerevisiae, nor when it was transformed with an antisense ADC construct. This provides direct evidence that the ADC cDNA from pea encoded a functional, specific ADC activity and that S. cerevisiae is able to process correctly the protein. In the pea plant, gene expression of the ADC is high in young developing tissues like shoot tips, young leaflets and flower buds. Fully expanded leaflets and roots have much lower, but still detectable, levels of the ADC transcript. In the ovary and fruit, they are developmentally regulated, showing high levels of expression during the early stages of fruit growth, which in pea is mainly due to cell expansion. The observed changes in the steady-state levels of ADC mRNA alone, however, cannot account for the differences in ADC activity suggesting that other regulatory mechanisms must be acting.
已从豌豆（Pisum sativum (L.)）单性结实幼果的cDNA文库中分离出一个编码精氨酸脱羧酶（ADC，EC 4.1.1.19）的cDNA。推导的氨基酸序列与番茄、燕麦和大肠杆菌的ADC分别有74%、46%和35%的同源性。当豌豆ADC cDNA置于半乳糖诱导型酵母启动子CYC1 - GAL10的控制下并导入酿酒酵母时，它赋予了半乳糖调节的ADC活性表达。在酿酒酵母中表达的ADC活性被ADC活性的特异性抑制剂α - DL - 二氟甲基精氨酸（DFMA）抑制了99%。在未转化的酿酒酵母中未检测到活性，用反义ADC构建体转化时也未检测到活性。这提供了直接证据，表明豌豆的ADC cDNA编码了一种功能性的、特异性的ADC活性，并且酿酒酵母能够正确加工该蛋白质。在豌豆植株中，ADC的基因表达在幼嫩的发育组织如茎尖、幼叶和花芽中较高。完全展开的叶片和根中的ADC转录本水平低得多，但仍可检测到。在子房和果实中，它们受到发育调控，在果实生长的早期阶段显示出高水平的表达，在豌豆中这主要是由于细胞扩张。然而，仅观察到的ADC mRNA稳态水平的变化并不能解释ADC活性的差异，这表明一定有其他调节机制在起作用。
