Molecular cloning of insulin-like growth factor-1 complimentary DNA and promoter region in the domestic duck (Anas platyrhynchos)

Complementary DNA (cDNA) and the flanking region of insulin-like growth factor-l (lGF-l) of domesticated duck were cloned. The nucleotide sequence analysis of the cDNA showed seven and eight bases different, respectively, from chicken and turkey lGF-l cDNA within the coding region. The amino acid sequence of prepro lGF-l differed by one and two amino acids from those observed in chicken and turkey, respectively. However, no amino acid substitution was observed in the mature lGF-l region. Sequence analysis of the promoter region and exon 1 of the duck lGF-l revealed a high degree of similarity to that of the chicken lGF-l gene. These results suggest that the mechanisms which regulate expression of the lGF-l gene may be widely conserved in avian species.