STRUCTURE OF THE GENE FOR THE TESTIS-SPECIFIC PROPROTEIN CONVERTASE-4AND OF ITS ALTERNATE MESSENGER-RNA ISOFORMS

Proprotein convertase 4 (PC4) is a mammalian secretory serine endoprot einase similar to the yeast KEX2 gene product and specifically express ed in testicular germs cells. PC4 mRNA isoforms that vary in size and 3' coding sequence have been reported (N. G. Seitah, R. Day, J. Hameli n, A. Gaspar, M. W. Collard, and M. Chretien, 1992, Mol. Endocrinol. 6 : 1559-1570). To determine the origin of these various forms, the mous e PC4 gene was cloned and its organization determined. The structural gene is approximately 9.5 kb long. It contains 15 exons and 14 introns . The exon-intron organization is very similar to that of the genes fo r the related convertases furin, PC1, and PC2. The upstream region car ries several GGGCGG and three CCAAT but no TATAA motifs. Analysis of t he 5' end of PC4 mRNA in the testis has led to the identification of t wo novel 5' splice variants that might encode a nonsecretory enzyme. T he multiple forms of PC4 mRNA can all be explained by alternate splici ng of primary transcripts of a single gene. (C) 1994 Academic Press, I nc.