Raymoure W J, McNaught R W, Smith R G
Nature. 1985;314(6013):745-7. doi: 10.1038/314745a0.
Two high-affinity oestrogen receptors have been identified in the chick oviduct with equilibrium dissociation constants (Kd) of 0.1 and 1 nM, differing in their binding kinetics, role in ovalbumin synthesis and independent regulation in vivo. The higher-affinity receptor (X) increases RNA polymerase II activity directly, whereas the low-affinity receptor (Y) seems to be necessary to confer specificity to transcription of oestrogen-dependent genes. Acute administration of progesterone to oestrogen-stimulated chicks results in preferential destruction of the nuclear Y receptor accompanied by interruption of ovalbumin gene transcription. Here we demonstrate that receptor Y exists in a non-oestradiol binding form (Ynb) which can be activated to the binding form in vitro by treatment with either ATP or ADP. Furthermore, dialysis of oviduct cytosol, which has no effect on the high-affinity receptor X, converts receptor Y to Ynb; receptor Y can then be recovered by treatment with ATP in the presence of Mg2+ and independently of Ca2+. This is the first report of the controlled interconversion between a non-steroid binding form of oestrogen receptor and active receptor in a tissue that contains two independently regulated oestrogen receptor types.
在鸡输卵管中已鉴定出两种高亲和力雌激素受体，其平衡解离常数（Kd）分别为0.1和1 nM，它们在结合动力学、卵清蛋白合成中的作用以及体内的独立调节方面存在差异。高亲和力受体（X）直接增加RNA聚合酶II的活性，而低亲和力受体（Y）似乎是赋予雌激素依赖性基因转录特异性所必需的。对雌激素刺激的雏鸡急性给予孕酮会导致核Y受体的优先破坏，并伴有卵清蛋白基因转录的中断。在此，我们证明受体Y以非雌二醇结合形式（Ynb）存在，通过用ATP或ADP处理可在体外将其激活为结合形式。此外，对输卵管胞质溶胶进行透析，这对高亲和力受体X没有影响，但会将受体Y转化为Ynb；然后在Mg2+存在下并用ATP处理，且与Ca2+无关，即可回收受体Y。这是关于在含有两种独立调节的雌激素受体类型的组织中，雌激素受体的非类固醇结合形式与活性受体之间受控相互转化的首次报道。
