Stimulation of intestinal calcium-binding-protein mRNA synthesis in the nucleus of vitamin D-deficient chicks by 1,25-dihydroxycholecalciferol.
Stimulation of intestinal calcium-binding-protein mRNA synthesis in the nucleus of vitamin D-deficient chicks by 1,25-dihydroxycholecalciferol.
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1,25-二羟基胆钙化醇刺激缺乏维生素 D 的雏鸡细胞核中肠钙结合蛋白 mRNA 的合成。
作者：
R. Spencer;M. Charman;D. Lawson
激素1，25-二羟基胆钙醇对肠道钙转运的刺激似乎涉及到RNA转录和新蛋白质的合成。虽然这些蛋白质中的一种已被鉴定为钙结合蛋白，但尚未鉴定出核内激素特异性诱导的RNA分子。对维生素D缺乏雏鸡在激素或胆钙化醇处理前和处理后不同时间间隔的肠道核RNA进行了检测，以确定其在无细胞系统中编码钙结合蛋白的能力。钙结合蛋白基因的表达在给予类固醇后2小时才能在肠核中检测到，这与在多聚核糖体中首次检测到钙结合蛋白的时间相同。因此，1，25-二羟基胆钙化醇通过刺激新的钙结合蛋白的核内新的信使核糖核酸分子的形成和快速释放来诱导该蛋白的产生。只有当它被合成时，它的多核糖体翻译才会继续，并且脉冲剂量125 ng的激素后的最大合成速度与用胆钙化醇长期刺激后观察到的速度相同。讨论了在肠道内激素积累和活性钙结合蛋白mRNA出现之间的间隔期内，细胞核内可能发生其他1，25-二羟胆钙醇依赖事件的可能性，并讨论了这些事件可能最终控制该mRNA的合成。
Stimulation of intestinal calcium transport by the hormone 1,25-dihydroxycholecalciferol appears to involve RNA transcriptions and the synthesis of new proteins. Although one of these proteins has been identified as calcium-binding protein, no RNA molecules specifically induced by the hormone in the nucleus have been identified. Nuclear RNA from intestine of vitamin D-deficient chicks before and at various time intervals after treatment with the hormone or cholecalciferol was tested for its ability to code for calcium-binding protein in a cell-free system. Calcium-binding-protein mRNA could only just be detected in the intestinal nuclei 2h after dosing with these steroids which is the same time that it was first observed in the polyribosomes. Thus 1,25-dihydroxycholecalciferol induces the production of new calcium-binding protein by stimulating the formation and rapid release from the nucleus of new mRNA molecules for this protein. Polyribosomal translation of the mRNA continued only as long as it was being synthesized, and the maximum rate of synthesis following a pulse dose of 125ng of the hormone was the same as that observed after prolonged stimulation with cholecalciferol. The possibility that other 1,25-dihydroxycholecalciferol-dependent events may be occurring in the nucleus in the lag period between accumulation of the hormone in the intestine and the appearance of active calcium-binding-protein mRNA, and that these may ultimately control the synthesis of that mRNA, is discussed.