Comparison of mammalian, chicken and Xenopus brain-derived neurotrophic factor coding sequences

We have used the polymerase chain reaction (PCR) to amplify and clone coding sequences of the mature region of brain-derived neurotrophic factor (BDNF) from monkey, rat, chicken and Xenopus genomic DNA. Consistent with previous reports, the predicted amino acid sequences obtained in this manner from monkey and rat were identical to other mammalian BDNF sequences. The chicken and Xenopus BDNF sequences are also highly conserved, but contain 7 and 8 amino, acid substitutions, respectively, compared to mammalian BDNF. Comparison of these sequences with the homologous NGF and NT3 coding regions provides further insight into amino acid residues that may be responsible for the different receptor specificities of these factors.