The human MJD gene: genomic structure and functional characterization of the promoter region

Abstract

Machado–Joseph disease (MJD) is a progressive neurodegenerative disorder caused by expansion of a CAG motif within the translated region of the human MJD ( hMJD) gene which has been mapped to chromosome 14q. In this study, the hMJD gene was identified in two overlapping bacterial artificial chromosome (BAC) clones and contained 11 exons resulting in a 6.14 kb transcript. The 5′-flanking region of the hMJD gene included a TATA-less promoter with GC-rich regions, a CCAAT box and multiple potential SP1 binding sites. Luciferase reporter assays performed in neuronal and non-neuronal human cell lines demonstrated a core promoter within the 200 bp region immediately upstream of the putative transcriptional start site (−89 according to the start codon). DNA–protein interactions defined by electrophoretic mobility shift assays (EMSA) revealed specific binding of nuclear proteins to the putative core promoter region.