Characterization of the complete genomic structure of the human versican gene and functional analysis of its promoter

Versican is a modular proteoglycan involved in the control of cellular growth and differentiation. To understand versican gene regulation and transcriptional control, we have isolated genomic clones spanning the entire gene locus including 5'- and 3'-flanking sequences. Versican was encoded by 15 exons encompassing over 90 kilobase pairs of continuous DNA. The exon organization corresponded to the protein subdomains encoded by homologous proteins, with a remarkable conservation of exon size and intron phase. We discovered an additional exon just proximal to the glycosaminoglycan-binding region that was identical to a recently identified splice variant of versican (Dours-Zimmermann, M.T., and Zimmermann, D.R. (1994) J. Biol. Chem. 269, 32992-32998). The versican promoter harbored a typical TATA box located approximately 16 base pairs upstream of the transcription start site and binding sites for a number of transcription factors involved in regulated gene expression. This promoter was shown to be highly functional in transiently transfected cells of both mesenchymal and epithelial origin. Stepwise 5' deletions identified a strong enhancer element between -209 and -445 base pairs and a strong negative element between -445 and -632 base pairs. This study provides the molecular basis for discerning the transcriptional control of the versican gene and offers the opportunity to investigate genetic disorders linked to this important human gene.