Gene sequences of chicken BDNF and NT-3.

The respective amino acid sequences of mature brain-derived neurotrophic factor (BDNF) and of mature neurotrophin-3 (NT-3) are identical among mammals, making these among the structurally conserved factors known. Here we show that only a single conservative amino acid substitution distinguishes the chicken mature NT-3 protein from its mammalian counterpart. Chicken mature BDNF shows slightly more variation, differing from mammalian BDNF at several positions. We also note the presence of amino acid sequence motifs in the precursor protein sequences of chicken BDNF and NT-3 that are universally conserved among all known mammalian neurotrophin precursors and have been demonstrated to play a crucial role in promoting correct processing of the pro-proteins.