Korn L J, Siebel C W, McCormick F, Roth R A
Science. 1987 May 15;236(4803):840-3. doi: 10.1126/science.3554510.
The oncogene protein product (p21) of the ras gene has been implicated in mediating the effects of a variety of growth factors and hormones. Microinjection of monoclonal antibody 6B7, which is directed against a synthetic peptide corresponding to a highly conserved region of p21 (amino acids 29 to 44) required for p21 function, specifically inhibited Xenopus oocyte maturation induced by incubation with insulin. The inhibition was dose-dependent and specific since (i) the same antibody had no effect on progesterone-induced maturation, (ii) immunoprecipitation and Western blotting indicated that the antibody recognized a single protein of molecular weight 21,000 in oocyte extracts, and (iii) inhibition was not observed with identical concentrations of normal immunoglobulin. Thus, p21 appears to be involved in mediating insulin-induced maturation of Xenopus oocytes. Furthermore, the mechanism may involve phosphorylation of p21, as p21 was found to be a substrate of the insulin receptor kinase.
ras基因的癌基因蛋白产物（p21）被认为在介导多种生长因子和激素的作用中发挥作用。微注射针对与p21功能所需的高度保守区域（氨基酸29至44）相对应的合成肽的单克隆抗体6B7，可特异性抑制胰岛素孵育诱导的非洲爪蟾卵母细胞成熟。这种抑制是剂量依赖性的且具有特异性，原因如下：（i）相同抗体对孕酮诱导的成熟没有影响；（ii）免疫沉淀和蛋白质印迹表明该抗体在卵母细胞提取物中识别出一种分子量为21,000的单一蛋白质；（iii）相同浓度的正常免疫球蛋白未观察到抑制作用。因此，p21似乎参与介导胰岛素诱导的非洲爪蟾卵母细胞成熟。此外，该机制可能涉及p21的磷酸化，因为发现p21是胰岛素受体激酶的底物。
