In this study we mapped the transcriptional initiation site of the gene for seminalplasmin (SAP) by primer extension analysis, situated 125 nucleotides upstream of the translational initiation site of the SAP-specific mRNA. We showed that the TATA-box in position -30 of the SAP gene is part of a functional promoter. A 280 bp region of the 5'-flanking region exerted a strong positive effect on promoter activity. In this region we identified consensus sequences for the transcriptional control elements AP1, AP2, PEA3 and GATA.