Human galactocerebrosidase gene: promoter analysis of the 5'-flanking region and structural organization

摘要

Galactocerebrosidase (GALC; EC 3.2.1.46) is a lysosomal enzyme which hydrolyzes several galactolipids and the deficiency of GALC is responsible for Krabbe disease. Recently, we cloned cDNAs for human and murine GALC. In this study we characterized the genomic organization and the promoter of the human gene. The gene was about 60kb in length and consisted of 17 exons as reported by Luzi et al. [1]. DNA sequence analysis showed that the 5'-flanking region of the first exon was GC-rich and had not typical TATA-box but ten GC-box-like sequences within a 200bp sequence upstream from the initiation codon. Another inframe ATG, which has better Kozak Consensus sequence, was found at 48bp upstream to the first ATG reported [1]. Promoter analysis using a luciferase assay in COS 7 cells showed that the -149 to -112 nucleotide (from the initiation codon A) region has dominant promoter activity. In this region three GC-box-like sequence and one YY1 binding site were detected. Primer extension revealed several transcription start sites within the region of -146 to -103 nucleotide. In this study we firstly demonstrated that the YY1 binding site and subsequent GC-box-like sequences could be a promoter in a housekeeping gene.