title: 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.
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.
authors.affiliation: Ottawa Civic Hospital Loeb Research Institute, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Zhu
authors.forename: N
authors.initials: N
authors.lastname: Ohan
authors.forename: Y
authors.initials: Y
authors.lastname: Agazie
authors.forename: C
authors.initials: C
authors.lastname: Cummings
authors.forename: S
authors.initials: S
authors.lastname: Farah
authors.forename: X J
authors.initials: XJ
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D007328:Insulin / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000502:physiology; D014981:Xenopus / Q000196:embryology*
chemical_list: D007328:Insulin; D017526:Receptor, IGF Type 1