cDNA sequence and tissue-specific expression of a basic liver-type fatty acid binding protein in adult zebrafish (Danio rerio).

We have determined the nucleotide sequence for a cDNA clone derived from zebrafish (Danio rerio) that codes for a fatty acid binding protein (FABP). Amino acid sequence similarity of the zebrafish FABP was highest to FABPs isolated from the livers of catfish, chicken, salamander and iguana. The open-reading frame of the zebrafish FABP cDNA codes for a protein of 14.0 kDa with a calculated isoelectric point of 8.8. The zebrafish liver-type FABP (L-FABP) cDNA hybridized to single restriction fragments of total zebrafish genomic DNA digested with the restriction endonucleases HaeIII or EcoRI suggesting that a single copy of the L-FABP gene is present in the zebrafish genome. Northern blot analysis demonstrated that the zebrafish L-FABP cDNA hybridized to a transcript of 700 nucleotides in total zebrafish RNA. In situ hybridization and emulsion autoradiography revealed that the L-FABP was expressed exclusively in the liver of the adult zebrafish. Based on amino acid sequence similarity, the isoelectric point and its tissue-specific pattern of expression, we conclude that this zebrafish FABP belongs to the basic liver-type FABPs only found, thus far, in non-mammalian vertebrates.