Genes for the insulin receptor and the insulin-like growth factor I receptor are expressed in the chicken embryo blastoderm and throughout organogenesis.
The early expression of insulin and insulin-like growth factor I (IGF-I) in the chicken embryo suggests that these peptides play an important role in early development. The receptors for insulin and IGF-I, however, had not been studied at the molecular level in this model. We report two chicken sequences that, by comparison with known tyrosine kinases, appear to correspond to the tyrosine kinase domain of the insulin receptor homologue (CTK-1) and the IGF-I receptor homologue (CTK-2). Using reverse-transcription of RNA, amplification with the polymerase chain reaction (RT-PCR), and gene-specific hybridization, we demonstrate that the two genes, CTK-1 and CTK-2, are expressed in embryos at least as early as the blastoderm (Day 0), during neurulation (Day 1), and in early (Days 2-3) and late (Day 9) organogenesis.
Scavo
L M
LM
Section on Receptors and Hormone Action, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Serrano
J
J
Roth
J
J
de Pablo
F
F
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001756:Blastoderm / Q000502:physiology*; D002642:Chick Embryo / Q000502:physiology*; D003001:Cloning, Molecular; D015870:Gene Expression; D005796:Genes; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction / Q000379:methods; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D011972:Receptor, Insulin / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000235:genetics*; D017451:Receptors, Somatomedin; D012689:Sequence Homology, Nucleic Acid
D015345:Oligonucleotide Probes; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D012313:RNA; D007334:Insulin-Like Growth Factor I; D011505:Protein-Tyrosine Kinases; D011972:Receptor, Insulin