Progesterone-binding components of chick oviduct. VIII. Receptor activation and hormone-dependent binding to purified nuclei.
Progesterone-binding components of chick oviduct. VIII. Receptor activation and hormone-dependent binding to purified nuclei.
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鸡输卵管的黄体酮结合成分。
DOI：
10.1016/s0021-9258(19)41856-5
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
B. O’Malley
中科院分区：
文献类型：
--
作者：
R. Buller;D. Toft;W. Schrader;B. O’Malley
建立了一种从雌激素致敏的鸡输卵管制备的无细胞系统，并用于研究离体细胞核对胞质内孕酮受体复合物的摄取。受体和纯化的细胞核在25 ℃下稳定，但在37 ℃下不稳定。因此，核孵育通常在25 ℃下进行。与在0 ℃下进行的对照孵育相比，这样的孵育揭示了细胞质的蛋白酶-受体复合物的更大的核摄取。摄取过程中表现出输卵管核的定量偏好。当细胞核在25 ℃下在不存在细胞质组分的情况下预孵育时，在0 ℃孵育期间没有发生净摄取。与此相反，通过在0度下与细胞核孵育之前在25度下预孵育酶-受体复合物，部分去除了温度要求。核摄取并不伴随着孕酮受体的沉降特性的可测量的改变。受体的活化和核摄取明显依赖于类固醇激素与受体的预先结合，表明在没有激素的情况下不能产生受体的活性核形式。用硫酸铵沉淀受体也部分地去除了核结合的温度要求。与温度激活相反，硫酸铵沉淀在没有激素的情况下激活受体。因此，温度和盐对受体的激活可能通过不同的机制发生。虽然我们能够破坏高达60%的细胞核DNA含量的处理与DNA酶之前，细胞核孵育，约80至85%的受体结合能力仍然存在于处理的细胞核。因此，鸡孕酮受体显然结合到输卵管基因组的相对DNA酶抗性部分。该系统的性质表明其价值为进一步调查的初始事件孕酮行动的鸡输卵管。
A cell-free system prepared from the estrogen-primed chick oviduct was developed and used to study the uptake of cytoplasmic progesterone-receptor complex by isolated nuclei. The receptor and purified nuclei were shown to be stable at 25 degrees, but not at 37 degrees. Thus, nuclear incubations were routinely performed at 25 degrees. Such incubations revealed greater nuclear uptake of the cytoplasmic hormone-receptor complex as compared to control incubations performed at 0 degrees. The uptake process showed a quantitative preference for oviduct nuclei. No net uptake occurred during 0 degrees incubations when the nuclei were preincubated in the absence of cytoplasmic components at 25 degrees. In contrast, the temperature requirement was partially removed by preincubation of the hormone-receptor complex at 25 degrees prior to incubation with nuclei at 0 degrees. Nuclear uptake was not accompanied by measurable alterations in the sedimentation properties of the progesterone receptor. The activation and nuclear uptake of receptor was clearly dependent upon prior binding of steroid hormone to the receptor indicating that the active nuclear form of the receptor could not be generated in the absence of the hormone. Receptor precipitation with ammonium sulfate also partially removed the temperature requirement for nuclear binding. In contrast to temperature activation, ammonium sulfate precipitation activated the receptor in the absence of hormone. It thus seemed likely that temperature and salt activation of receptor occurred via different mechanisms. Although we were able to destroy up to 60% of the nuclear DNA content by treatment with DNase prior to nuclear incubation, some 80 to 85% of the receptor-binding capacity was still present in the treated nuclei. Thus, chick progesterone receptors apparently bind to a relatively DNase-resistant portion of the oviduct genome. The properties of this system indicate its value for further investigation into the initial events of progesterone action in the chick oviduct.