Tawfic S, Goueli S A, Olson M O, Ahmed K
Cellular and Molecular Biochemistry Research Laboratory (151), University of Minnesota, Minneapolis 55417.
Cell Mol Biol Res. 1993;39(1):43-51.
Protein B23 is a nucleolar and nuclear matrix phosphoprotein which has been implicated in ribosomal assembly and/or rRNA processing. Since androgen action in the prostate is accompanied by early changes in rRNA synthesis, we have investigated androgenic regulation of protein B23 expression and phosphorylation in rat ventral prostatic nuclei. The mRNA for prostatic protein B23 was relatively stable and decreased only after several days of androgen deprivation. However, androgen deprivation resulted in a rapid change in the amount and phosphorylation of protein B23 in prostatic nuclei, which was reversed on administration of androgens to orchiectomized animals. Phosphorylation of protein B23 appears to be catalyzed primarily by casein kinase 2 (CK-2). Early androgenic changes in phosphorylation of protein B23 appear to relate more to modulations in the protein kinase activity than in the amount of protein B23. The androgen mediated enhancement in the amount of protein B23 and its phosphorylation precedes the cellular proliferative phase following androgen administration to castrated rats, and appear to be temporally concordant with the rRNA synthesis in the tissue. The androgen mediated changes in the amount and phosphorylation of protein B23 are specific to the prostate and are not detected in the liver nuclei. Thus, androgenic regulation of the amount and phosphorylation of prostatic protein B23 may be related to the early changes associated with androgen mediated growth of the gland.
蛋白质B23是一种核仁及核基质磷蛋白，与核糖体组装和/或核糖体RNA（rRNA）加工有关。由于前列腺中的雄激素作用伴随着rRNA合成的早期变化，我们研究了大鼠腹侧前列腺细胞核中蛋白质B23表达和磷酸化的雄激素调节。前列腺蛋白质B23的信使核糖核酸（mRNA）相对稳定，仅在雄激素剥夺几天后才减少。然而，雄激素剥夺导致前列腺细胞核中蛋白质B23的量和磷酸化迅速变化，对去势动物给予雄激素后这种变化会逆转。蛋白质B23的磷酸化似乎主要由酪蛋白激酶2（CK - 2）催化。蛋白质B23磷酸化的早期雄激素变化似乎更多地与蛋白激酶活性的调节有关，而不是与蛋白质B23的量有关。给去势大鼠注射雄激素后，雄激素介导的蛋白质B23量及其磷酸化的增加先于细胞增殖期，并且似乎在时间上与组织中的rRNA合成一致。雄激素介导的蛋白质B23量和磷酸化的变化是前列腺特有的，在肝细胞核中未检测到。因此，前列腺蛋白质B23量和磷酸化的雄激素调节可能与雄激素介导的前列腺生长相关的早期变化有关。
