ANALYSIS OF THE 5'-FLANKING REGION OF THE HUMAN GALACTOCEREBROSIDASE (GALC) GENE

Galactocerebrosidase (GALC) is the lysosomal enzyme deficient in human and certain animal species with globoid cell leukodystrophy (GLD) or Krabbe disease. It catalyzes the hydrolysis of specific galactolipids including galactosylceramide and psychosine. The GALC protein is found in very low amounts in all tissues, which delayed its purification an d the subsequent cloning of its cDNA and gene. We previously published the exon-intron organization of the human gene, but did not functiona lly analyze the 5' flanking region, We now provide a description of th is GC-rich region which includes one potential YY1 element and one pot ential SP1 binding site. There are 13 GGC trinucleotides within the fi rst 150 bp preceding the initiation codon, The 5' end of intron 1 cont ains six potential Sp1 binding sites, one AP1 binding site, and eight AP2 binding sites. A construct containing nucleotides -176 to -24 had the strongest promoter activity using a vector containing the chloramp henicol acetyltransferase reporter gene. We also provide evidence for the presence of inhibitory sequences located immediately upstream of t he promoter region, and within the first 234 nucleotides of intron 1. These elements together with a suboptimal nucleotide at position +4 ma y explain the low level of GALC protein in all cell types. (C) 1997 Ac ademic Press.