Conneely O M, Maxwell B L, Toft D O, Schrader W T, O'Malley B W
Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Biochem Biophys Res Commun. 1987 Dec 16;149(2):493-501. doi: 10.1016/0006-291x(87)90395-0.
In order to establish the origin of the A and B proteins of the chicken progesterone receptor we have expressed its cDNA in vivo in heterologous cells and in vitro in reticulocyte cell lysates. The A and B proteins were expressed from a single cDNA both in heterologous receptor negative cells and in a cell-free system. Both proteins bind progesterone and are indistinguishable from chick oviduct authentic A and B proteins in terms of size, immunoreactivity and hormone binding properties. Truncated mRNA's which lack the receptor B protein translation signal are capable of generating the receptor A protein by initiation of translation at a second internal start site. We conclude from these data that the chicken progesterone receptor A and B proteins arise most likely by alternate initiation of translation from a single mRNA transcript.
为了确定鸡孕酮受体A和B蛋白的来源，我们已在异源细胞中进行体内表达，并在网织红细胞裂解物中进行体外表达。A和B蛋白均由单一cDNA在异源受体阴性细胞和无细胞系统中表达。两种蛋白都能结合孕酮，且在大小、免疫反应性和激素结合特性方面与鸡输卵管中的天然A和B蛋白没有区别。缺少受体B蛋白翻译信号的截短mRNA能够通过在第二个内部起始位点启动翻译来产生受体A蛋白。从这些数据我们得出结论，鸡孕酮受体A和B蛋白很可能是由单一mRNA转录本的交替起始翻译产生的。
