CLONING THE CHICKEN LEPTIN GENE

Chicken is characterized by a relative insulin resistance and a physio logical hyperglycemia (2g/L) and is also subjected to fattening. Fat d eposits in chicken, as in mammals, are regulated by environmental and genetic factors. In mammals, leptin, an adipose cell-specific secreted protein has been characterized that is encoded by ob gene. Leptin reg ulates satiety through hypothalamic specific receptors, energy balance , energy efficiency and contributes to adaptation to starvation. The l eptin gene has been characterized in various mammalian species, and th e cloning and sequencing of the chicken leptin gene (ob gene) are repo rted. Using RT-PCR and primers flanking the coding region of the lepti n gene selected from known mammalian sequences, we have successfully a mplified a 600-bp fragment from chicken liver and adipose tissue total ARNs. The amplified fragment exhibits a similar size to that of the c oding region of the mammalian leptin gene. The sequences of the coding region of chicken liver and adipose tissue are identical and presente d 97%, 96% and 83% similarity to the mouse, rat and human sequences, r espectively. Finally, this is the first report showing that leptin gen e expression in chicken is not exclusively localized in adipose tissue but is also expressed in liver. The expression of leptin in liver may be associated with a key role of this organ in avian species in contr olling lipogenesis. (C) 1998 Elsevier Science B.V.