Chang M, Reddy C C
Environmental Resources Research Institute, Pennsylvania State University, University Park 16802.
Biochem Biophys Res Commun. 1991 Dec 31;181(3):1431-6. doi: 10.1016/0006-291x(91)92099-6.
Selenium-dependent glutathione peroxidase (Se-GSH-Px, Ec.1.11.1.9) is the best characterized selenoenzyme in higher animals. However, neither the mechanism whereby selenium (Se) becomes incorporated into the enzyme nor the level at which the expression of Se-GSH-Px gene is regulated by Se is fully understood. In the current investigation, we have determined the relative rates of the transcription of the Se-GSH-Px gene in purified liver nuclei isolated from rats fed on Se-supplemented or Se-deficient diets. No significant difference in the transcription rates appeared in these two groups. These results are consistent with the previous observations that active message for Se-GSH-Px- that is, translatable mRNA for Se-GSH-Px- is present in Se-deficient tissues (Li et al., J. Biol. Chem., 265, 108-113, 1990). The data also suggest that the alteration of Se-GSH-Px activity and the corresponding protein and mRNA levels in rats subjected to dietary Se manipulation can be attributed only to post-transcriptional regulation.
硒依赖型谷胱甘肽过氧化物酶（Se-GSH-Px，Ec.1.11.1.9）是高等动物中特征最为明确的含硒酶。然而，硒（Se）掺入该酶的机制以及Se-GSH-Px基因表达受硒调控的水平仍未完全明确。在当前研究中，我们测定了从喂食含硒或缺硒日粮的大鼠分离出的纯化肝细胞核中Se-GSH-Px基因的相对转录速率。这两组的转录速率未出现显著差异。这些结果与先前的观察结果一致，即在缺硒组织中存在Se-GSH-Px的活性信息，即Se-GSH-Px的可翻译mRNA（Li等人，《生物化学杂志》，265，108 - 113，1990）。数据还表明，饮食中硒含量改变的大鼠体内Se-GSH-Px活性以及相应蛋白质和mRNA水平的变化仅可归因于转录后调控。
