Characterization of the 5′ flanking region of the growth hormone gene of the marine teleost, gilthead sea bream Sparus aurata: analysis of a polymorphic microsatellite in the proximal promoter

The 5′ flanking region (1712 bp) of the growth hormone (GH) gene of the gilthead sea bream Sparus aurata was cloned, sequenced and characterized. It contains a consensus sequence for TATA box and several Pit-1 binding site motifs. Consensus sequences related to cyclic AMP response element, glucocortiocoid response element, and several other transcription factors were identified by comparison to consensus sequences in fish or mammalian GH genes. The promoter contains two microsatellites (di- and tri-nucleotides repeats) with additional upstream microsatellites (tri-and tetranucleotides), 10-mer tandem repeat, and two long inverted repeats. Analysis of the proximal dinucleotide microsatellite by polymerase chain reaction revealed polymorphism among individuals from a hatchery population and an association of alleles 250 and 254 with growth performance. Segregation analysis of this marker in one family showed Mendelian inheritance. These results suggest that the microsatellite in the promoter region (termed saGHpCA) might be considered as a candidate genetic marker for broodstock management and growth selection programs of Sparus aurata.