Characterization of a mouse mitogen-regulated protein/proliferin gene and its promoter: a member of the growth hormone/prolactin gene superfamily.

A genomic clone containing the complete gene, designated mrp/plf3, of a member of the mitogen-regulated protein/proliferin (MRP/PLF) multi-gene family was isolated from a mouse genomic library constructed in lambda L47.1. The DNA sequences of the 5' flanking region, the exons, and the exon/intron boundaries have been determined. The size and organization of the five exons in the murine mrp/plf3 gene are very similar to those of members of the prolactin/growth hormone family, confirming that mrp/plf3 is a part of this superfamily. Removal of an upstream negative regulatory element revealed an active mrp/plf promoter that was responsive to TGF-alpha and contains known regulatory elements. Intracellular mrp/plf mRNA levels were increased by 17 beta-estradiol and reduced by dexamethasone.