The seminal vesicle secretion IV gene: detection of S1 nuclease-sensitive sites in supercoiled plasmid pSVS 3.3.

We have investigated the sites sensitive to the S1 nuclease which are presented in a supercoiled plasmid, pSVS 3.3. This plasmid contains the entire transcription unit plus 5'- and 3'-flanking regions of the rat seminal vesicle IV gene on a 3.3 kb Eco RI fragment (Harris et al., 1983). Using a cDNA probe of rat seminal vesicle secretion product IV (SVS IV) mRNA, we have demonstrated S1 nuclease-sensitive sites in the 5'-flanking and in the 3'-flanking regions of SVS IV gene. The site in the 5'flanking region has been mapped to approximately 117 bp upstream from the CAP site. This site at -117 bp can potentially form a cruciform structure as inferred from the presence of inverted repeats in this region (Lilley, 1981; Panayotatos and Wells, 1981). We have now shown such a structure most probably exists. The S1 nuclease-sensitive site in the 3'flanking region is present in an area of highly repeated sequence.