McIntosh R P, Catt K J
Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1987 Dec;84(24):9045-8. doi: 10.1073/pnas.84.24.9045.
The expression of several neurotransmitter and drug receptors from injected exogenous mRNA in Xenopus laevis oocytes has been demonstrated by electrophysiological measurements of ion channel activation. The expression of specific receptors for peptide hormones in such a translation system would facilitate studies on the structure and regulation of cell-surface receptors as well as their coupling to membrane transduction mechanisms. The expression of receptors for calcium-mobilizing hormones in Xenopus oocytes was sought by analysis of phospholipid turnover in hormone-stimulated oocytes. For this purpose, Xenopus oocytes were injected with mRNA extracted from bovine adrenal and pituitary glands and incubated with myo-[3H]inositol to label plasma-membrane phosphatidylinositol phosphates. The expression of functionally active receptors for angiotensin II (AII) and thyrotropin-releasing hormone (TRH) was demonstrated by the stimulation of [3H]inositol phosphate production by AII and TRH in the mRNA-injected, [3H]inositol-prelabeled oocytes. The ability of AII and TRH to act by way of newly synthesized receptors from mammalian endocrine tissues to stimulate phosphatidylinositol polyphosphate hydrolysis in Xenopus oocytes suggests a generalized and conserved mechanism of receptor coupling to the transduction mechanism responsible for activation of phospholipase C in the plasma membrane.
通过离子通道激活的电生理测量，已证实非洲爪蟾卵母细胞中注射的外源信使核糖核酸（mRNA）可表达多种神经递质和药物受体。在这样的翻译系统中肽类激素特异性受体的表达，将有助于对细胞表面受体的结构与调节及其与膜转导机制的偶联进行研究。通过分析激素刺激的卵母细胞中的磷脂转换，探寻非洲爪蟾卵母细胞中钙动员激素受体的表达。为此，将从牛肾上腺和垂体提取的mRNA注射到非洲爪蟾卵母细胞中，并用肌醇-[3H]标记以标记质膜磷脂酰肌醇磷酸。在注射了mRNA、用[3H]肌醇预标记的卵母细胞中，血管紧张素II（AII）和促甲状腺激素释放激素（TRH）刺激[3H]肌醇磷酸生成，从而证明了AII和TRH功能活性受体的表达。AII和TRH能够通过来自哺乳动物内分泌组织的新合成受体，刺激非洲爪蟾卵母细胞中的磷脂酰肌醇多磷酸水解，这表明受体与负责激活质膜中磷脂酶C的转导机制偶联存在一种普遍且保守的机制。
