Spelsberg T C, Cox R F
Biochim Biophys Acta. 1976 Jul 16;435(4):376-90. doi: 10.1016/0005-2787(76)90203-3.
The effects of estrogen, progesterone and estrogen + progesterone combined on nuclear transcriptional processes in oviducts of immature chicks, previously withdrawn from estrogen, are reported. The responses to the steroids of the endogenous nuclear RNA polymerase activities, both nucleolar (I) and nucleoplasmic (II), the chromatin compositions and template capacities, and the appearance of ovalbumin messenger RNA (mRNA) are compared. When immature chicks (previously treated at 14 days with estrogen) are withdrawn from estrogen treatment, there is a gradual reduction in both polymerase activities. Diurnal variations in polymerase II activties in the oviduct of withdrawn chicks required that subsequent experiments include time-matched controls. The hormones alter RNA polymerase II and II activities in vivo as assayed in isolated nuclei. Progesterone represses the polymerase I and II activities, while estrogen alone and estrogen + progesterone enhance both polymerase activities immediately after injection. Diethylstillbestrol, a synthetic estrogen, causes changes similar to those of estrogen. The effects of these steroids on the polymerases are detected within 15 min of hormone injection. Changes in the capacities of chromatins to serve as template for RNA synthesis in general correlated with changes in polymerase II activities. Interestingly, in the case of estrogen treatment, the acidic chromatin protein (but not histone) levels fluctuate positively with the template capacities of the chromatin. An antagonism between estrogen and progesterone is observed in the responses of both RNA polymerases I and II activities as well as in the chromatin template capacity. Levels of messenger RNA coding for ovalbumin, as detected by hybridization with labeled complementary DNA, increase in oviducts of withdrawn chicks within 2--3 of the injection of estrogen, progesterone or estrogen + progesterone. This rapid accumulation of ovalbumin mRNA is not accompanied in each case by a similar increase in polymerase II activity or chromatin template capacity.
本文报道了雌激素、孕酮以及雌激素与孕酮联合使用对先前已停用雌激素的未成熟雏鸡输卵管核转录过程的影响。比较了核仁（I）和核质（II）中内源性核RNA聚合酶活性、染色质组成和模板能力对这些类固醇的反应，以及卵清蛋白信使RNA（mRNA）的出现情况。当未成熟雏鸡（14日龄时曾用雌激素处理）停止雌激素处理后，两种聚合酶活性均逐渐降低。停用雌激素的雏鸡输卵管中聚合酶II活性的昼夜变化要求后续实验包括时间匹配的对照。在分离的细胞核中检测到，这些激素在体内改变RNA聚合酶II和I的活性。孕酮抑制聚合酶I和II的活性，而单独使用雌激素以及雌激素与孕酮联合使用在注射后立即增强两种聚合酶的活性。合成雌激素己烯雌酚引起的变化与雌激素类似。在激素注射后15分钟内即可检测到这些类固醇对聚合酶的影响。染色质作为RNA合成模板的能力变化通常与聚合酶II活性的变化相关。有趣的是，在雌激素处理的情况下，酸性染色质蛋白（而非组蛋白）水平与染色质的模板能力呈正相关。在RNA聚合酶I和II的活性反应以及染色质模板能力方面，观察到雌激素和孕酮之间存在拮抗作用。通过与标记的互补DNA杂交检测到，编码卵清蛋白的信使RNA水平在注射雌激素、孕酮或雌激素与孕酮联合使用后2 - 3小时内，在停用雌激素的雏鸡输卵管中升高。卵清蛋白mRNA的这种快速积累在每种情况下并不都伴随着聚合酶II活性或染色质模板能力的类似增加。
