DIFFERENTIAL REGULATION OF RAT-LIVER SELENOPROTEIN MESSENGER-RNAS IN SELENIUM DEFICIENCY
DIFFERENTIAL REGULATION OF RAT-LIVER SELENOPROTEIN MESSENGER-RNAS IN SELENIUM DEFICIENCY
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DOI：
10.1016/s0006-291x(05)80984-2
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发表时间：
1992-05-29
影响因子：
3.1
通讯作者：
BURK, RF
中科院分区：
文献类型：
--
作者：
HILL, KE;LYONS, PR;BURK, RF
缺硒会导致硒蛋白浓度下降，但硒蛋白P和I型碘甲腺原氨酸5‘-脱碘酶(5’-脱碘酶)比谷胱甘肽过氧化物酶更能抵抗这种影响。为了研究这些硒蛋白的差异调节，给断奶大鼠喂饲低硒饲料14.5周，用Northern分析方法测定它们的肝脏mRNAs。随着时间的推移，3种基因的表达水平均呈递减趋势。与对照组相比，硒蛋白P和5‘-脱碘酶的mRNAs在所有时间点都高于谷胱甘肽过氧化物酶的mRNAs。谷胱甘肽过氧化物酶活性和硒蛋白P浓度的降低反映了信使核糖核酸的减少。然而，蛋白质水平的下降大于它们的mRNAs的下降，这表明这两种蛋白质的合成在翻译水平上受到硒可用性的类似程度的限制。除了这种明显未受调控的翻译效应外，这些结果还指出了一种翻译前调节，影响了mRNA水平，这可能解释了缺硒对谷胱甘肽过氧化物酶和其他硒蛋白的不同影响。当可获得的元素数量有限时，这种调节可能有助于将硒直接转化为硒蛋白P和5‘-脱碘酶。
Selenium deficiency causes a fall in the concentrations of selenoproteins but selenoprotein P and type I iodothyronine 5′-deiodinase (5′-deiodinase) are more resistant to this effect than is glutathione peroxidase. To investigate the differential regulation of these selenoproteins, a selenium-deficient diet was fed to weanling rats for 14.5 weeks and their hepatic mRNAs were measured by Northern analysis. Levels of all 3 mRNAs fell progressively with time. Selenoprotein P and 5′-deiodinase mRNAs remained higher at all time points relative to control than glutathione peroxidase mRNA. mRNA decreases were mirrored by decreases in glutathione peroxidase activity and selenoprotein P concentration. However, the decreases in the protein levels were greater than the decreases in their mRNAs, suggesting that synthesis of both proteins was limited to a similar extent at the translational level by the availability of selenium. In addition to this apparently unregulated translational effect, these results point to a pretranslational regulation, affecting mRNA levels, which could account for the differential effect of selenium deficiency on glutathione peroxidase and the other selenoproteins. This regulation might serve to direct selenium to selenoprotein P and 5′-deiodinase when limited amounts of the element are available.