Cestelli A, Gristina R, Castiglia D, Di Liegro C, Savettieri G, Salemi G, Di Liegro I
Dipartimento di Biologia Cellulare e dello Sviluppo, Alberto Monroy, Palermo, Italy.
Neurochem Res. 1992 Nov;17(11):1049-55. doi: 10.1007/BF00967280.
The effect of triiodothyronine (T3) on the rate of synthesis of nuclear proteins was studied during terminal differentiation of rat cortical neurons cultured in a serum-free medium. To this aim total and acid soluble nuclear proteins were analyzed by different electrophoretic techniques. Our results show that: 1) during maturation in vitro, neuronal nuclei undergo a dramatic change in the rate at which different classes of histones and high mobility group (HMG) proteins are synthesized; the synthetic activity, measured as incorporation of radioactive precursors into nuclear proteins, slows indeed down with age: especially evident is the decrease in core histones synthesis; at day 15, on the other hand, HMG 14 and 17 and ubiquitinated H2A (A24) are synthesized at a high rate, especially in T3-treated neurons; 2) neurons treated with T3 show, at any age tested, a higher level of lysine incorporation into nuclear proteins; 3) even if during the first days of culture neurons synthesize core histones more actively in the presence of T3, there is no accumulation of these proteins at later stages, as compared with untreated cells. Possible implications of these data and relationship with the chromatin rearrangement which accompanies neuronal terminal differentiation are discussed.
在无血清培养基中培养的大鼠皮质神经元终末分化过程中，研究了三碘甲状腺原氨酸（T3）对核蛋白合成速率的影响。为此，采用不同的电泳技术分析了总核蛋白和酸溶性核蛋白。我们的结果表明：1）在体外成熟过程中，神经元细胞核中不同类别的组蛋白和高迁移率族（HMG）蛋白的合成速率发生了显著变化；以放射性前体掺入核蛋白来衡量的合成活性确实随着年龄的增长而减慢：核心组蛋白合成的减少尤为明显；另一方面，在第15天，HMG 14和17以及泛素化的H2A（A24）合成速率很高，尤其是在T3处理的神经元中；2）在任何测试年龄，用T3处理的神经元核蛋白中赖氨酸掺入水平更高；3）即使在培养的最初几天，神经元在T3存在下更活跃地合成核心组蛋白，但与未处理的细胞相比，后期这些蛋白没有积累。讨论了这些数据的可能意义以及与神经元终末分化伴随的染色质重排的关系。
