Carr F E, Jump D B, Oppenheimer J H
Endocrinology. 1984 Nov;115(5):1737-45. doi: 10.1210/endo-115-5-1737.
We investigated the possibility that hypothyroidism, like starvation, leads to a major disaggregation of polyribosomes and redistribution of mRNA to the nonpolysomal mRNA particle (mRNP) pool. The analysis involved the use of a translational assay of hepatic RNA obtained from bound and free polysomes and the subribosomal fractions (mRNP) of euthyroid and hypothyroid rats. Two-dimensional gel electrophoretograms of the in vitro synthesized 35S-labeled proteins revealed distinct protein patterns associated with each subcellular compartment. Of the 18 quantified T3-responsive sequences, the activities of 7 were preferentially associated with bound polysomes, 9 with free polysomes, and 2 with subribosomal mRNP in euthyroid rat livers. No major redistribution occurred in the transition from the euthyroid to the hypothyroid state. The distribution of mRNA activity of 1 T3-responsive sequence, that coding for Spot 14 (mRNAS14), was compared with the distribution of hybridizable mRNA, as determined with the use of a specific cDNA probe. In the euthyroid state, both techniques showed that approximately 70% of the total hepatic mRNAS14 was associated with free polysomes and 30% was associated with subribosomal complexes. A similar distribution was characteristic of the hypothyroid state. These findings demonstrate that T3-responsive sequences are found in all three mRNA compartments and that thyroid hormone action is not typically associated with a redistribution of mRNA among subcellular pools.
我们研究了甲状腺功能减退症是否像饥饿一样，会导致多核糖体的大量解聚以及信使核糖核酸（mRNA）重新分配至非多核糖体信使核糖核酸颗粒（mRNP）库的可能性。该分析涉及对正常甲状腺功能和甲状腺功能减退大鼠肝脏中结合型和游离型多核糖体以及核糖体亚组分（mRNP）的RNA进行翻译测定。体外合成的35S标记蛋白质的二维凝胶电泳图谱显示了与每个亚细胞区室相关的独特蛋白质模式。在18个定量的三碘甲状腺原氨酸（T3）反应性序列中，7个序列的活性优先与结合型多核糖体相关，9个与游离型多核糖体相关，2个与正常甲状腺功能大鼠肝脏中的核糖体亚组分mRNP相关。从正常甲状腺功能状态转变为甲状腺功能减退状态时，未发生重大重新分配。将1个T3反应性序列（即编码Spot 14的mRNA，mRNAS14）的mRNA活性分布与使用特异性cDNA探针测定的可杂交mRNA分布进行了比较。在正常甲状腺功能状态下，两种技术均显示，肝脏中mRNAS14总量的约70%与游离型多核糖体相关，30%与核糖体亚复合物相关。甲状腺功能减退状态也具有类似的分布特征。这些发现表明，在所有三个mRNA区室中均发现了T3反应性序列，并且甲状腺激素作用通常与mRNA在亚细胞池之间的重新分配无关。
