Structure of the tilapia (Oreochromis mossambicus) prolactin I gene

The tilapia (Oreochromis mossambicus) prolactin-I (PRL-I) gene has been cloned and sequenced. Its transcript (3,677 bases long) begins with a guanine and is organized in five exons and four introns like the other known prolactin genes. Analysis of the 1,555-bp 5'-flanking region suggests that pituitary-specific expression of the gene could be regulated through a trans-factor related to the mammalian pituitary-specific factor Pit-1. Two potential binding sites for such a factor were found in the first intron, suggesting a possible regulatory role for this region. Moreover, two potential Z-DNA regions are located at positions -837 to -812 and -246 to -179 from the transcription start site. These two regions could play an important role in the regulation of PRL gene expression.