Cloning and expression of the mouse pseudoautosomal steroid sulphatase gene (Sts)

Publisher Website
Google Scholar
Abstract
Steroid sulphatase (STS) Is an important enzyme in steroid metabolism1. The human STS gene has been cloned and mapped to Xp22.3, proximal to the pseudoautosomal region (PAR)2. Using quantitative differences in STS activity among various mouse strains, a segregation pattern consistent with autosomal linkage was first reported3–5, but more recent studies have linked Ste to the mouse PAR6–11. Failed attempts to clone the mouse Sfs gene using human reagents (STS cDNA and anti-STS antibodies) suggest a substantial divergence between these genes. However, partial amino-terminal sequence from purified rat liver Sts is very similar to its human counterpart12, and several domains are conserved among all the sulphatases13–14. We followed a degenerate-primer reverse transcriptase-PCR (RT-PCR) approach to amplify a conserved fragment of the rat Ste cDNA that was then used to clone the mouse Ste cDNA. This 2.3-kb cDNA revealed 75% similarity with rat Sfs cDNA, while it was only 63% similar to human STS cDNA. Transfection of STS(−) A9 cells with the mouse Sfs cDNA restored STS enzymatic activity. Sts was also mapped physically to the distal end of the mouse sex chromosomes, and our backcross studies placed Sts distal to the ‘obligatory’ crossover in male meiosis.