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Molecular cloning and characterization of Xenopus insulin-like growth factor-1 receptor: its role in mediating insulin-induced Xenopus oocyte maturation and expression during embryogenesis.

Research paper by L L Zhu, N N Ohan, Y Y Agazie, C C Cummings, S S Farah, X J XJ Liu

Indexed on: 10 Mar '98Published on: 10 Mar '98Published in: Endocrinology



Abstract

We have cloned a complementary DNA encoding the putative Xenopus insulin-like growth factor-1 (xIGF-1) receptor. Injection of messenger RNA derived from the cloned complementary DNA into Xenopus oocytes resulted in the expression and correct processing of the receptor's alpha- and beta-subunits. Using antibodies generated against protein expressed against the cloned sequence, we demonstrated that the endogenous xIGF-1 receptor in Xenopus oocytes was activated by nanomolar concentrations of mammalian IGF-1 and by insulin approximately 100-fold higher in concentration. This receptor activation profile correlated with hormone-induced Xenopus oocyte maturation. Furthermore, injection of a neutralizing antiinsulin receptor antibody into Xenopus oocytes inhibited hormone-induced xIGF-1 receptor activation. These results provide molecular and biochemical evidence supporting a role for xIGF-1 receptor in mediating insulin/IGF-1-induced Xenopus oocyte maturation. We also report here that embryonic transcription of xIGF-1 receptor is activated during the formation of the central nervous system in early Xenopus embryos.