Prolactin-induced expression of TATA-less cyclin D3 gene is mediated by Sp1 and AP2

The TATA-less cyclin D3 gene is stimulated by prolactin (PRL) in rat Nb2 T-lymphocytes. DNA mobility shift assay and luciferase transfection analysis revealed that the gene has a potential promoter region, two enhancer domanins and a silencer region. The promoter region possessed three Sp1 sites and two AP2 sites, and both enhancer regions had one AP2 binding site each. Analysis using oligonucleotide probes and purified AP2 protein has suggested that the expression of rat cyclin D3 gene is promoted by Sp1 and AP2 factors.