Hermesz E, Abrahám M, Nemcsók J
University of Szeged, Faculty of Science, Department of Biochemistry, P.O. Box 533, H-6701, Szeged, Hungary.
Comp Biochem Physiol C Toxicol Pharmacol. 2001 Mar;128(3):457-65. doi: 10.1016/s1532-0456(01)00165-x.
Two metallothionein cDNA isoforms (MT-1 and MT-2) were isolated from carp (Cyprinus carpio) by RT-PCR. Sequence analysis of the cDNAs revealed two amino acid differences between the coding regions and markedly different 3'-untranslated ends. Gene-specific primers were selected and used in RT-PCR reactions to measure the basal MT-1 and MT-2 mRNA levels and to follow the inducer-specific expression of MT genes in different tissues during in vivo studies. In the brain and muscle, the uninduced levels of the two MT mRNAs were similar. In the kidney and liver, the MT-1 gene product predominated, while in the heart the relative expression levels of the two genes were opposite. Both the MT-1 and MT-2 mRNA levels increased with Cd concentration in a time- and dose-dependent manner. The expression of MT-2, however, was more responsive to a high Cd concentration. In parallel with the induction of the MTs by Cd, we followed the accumulation of this metal in the kidney and liver. Although the Cd level was always higher in the kidney during treatment, the rate of accumulation was higher in the liver. Cold stress resulted in a significantly higher induction of MT-1 than of MT-2, while heat shock had no effect on the expression of either gene.
通过逆转录聚合酶链反应（RT-PCR）从鲤鱼（Cyprinus carpio）中分离出两种金属硫蛋白cDNA亚型（MT-1和MT-2）。对这些cDNA的序列分析显示，编码区之间存在两个氨基酸差异，并且3'-非翻译区明显不同。在体内研究期间，选择基因特异性引物并用于RT-PCR反应，以测量基础MT-1和MT-2 mRNA水平，并追踪MT基因在不同组织中的诱导剂特异性表达。在脑和肌肉中，两种MT mRNA的未诱导水平相似。在肾脏和肝脏中，MT-1基因产物占主导地位，而在心脏中，这两个基因的相对表达水平则相反。MT-1和MT-2 mRNA水平均随镉浓度的增加呈时间和剂量依赖性增加。然而，MT-2的表达对高镉浓度更敏感。与镉诱导MTs的同时，我们追踪了这种金属在肾脏和肝脏中的积累情况。尽管在治疗期间肾脏中的镉水平始终较高，但肝脏中的积累速率更高。冷应激导致MT-1的诱导明显高于MT-2，而热休克对这两个基因的表达均无影响。
