CHARACTERIZATION OF THE 5'-REGION OF THE ATLANTIC SALMON (SALMO-SALAR) TRANSFERRIN-ENCODING GENE

A genomic fragment encompassing the first two exons and 1.3-kb 5'-flan king sequence of the Atlantic salmon transferrin (Tf)-encoding gene (s Tf) has been isolated and characterized. The transcription start point of sTf was mapped to 48 nucleotides upstream from the translation sta rt codon. In the proximal promoter region (-118 to +1), sTf displays s equence similarity to the chicken, mouse and human Tf;and contains a T ATA-box, CCAAT-box and CAAAC motif conserved during evolution. Putativ e binding sites for the transcription factors AP-2, AP-3, Spl, CF1, NF -IL6, HNF-5, GCF and GATA-1 were identified in the sTf 5'-flanking seq uence. An element with dyad symmetry is located between -219 and -201, and an alternating purine-pyrimidine (APP) sequence (a 24-bp imperfec t CA repeat) is located at -187 to -164. A minisatellite consisting of 25 tandem repeats of a 37-bp motif occupies the region between -1338 and -417. The Atlantic salmon has two Tf genes. Comparison of the 5'-e nd sequences (nt -383 to +80) of the two sTf revealed only minor diffe rences, except that the length of a CA repeat differs by 12 bp.