Human histo-blood group ABO glycosyltransferase genes: different enhancer structures with different transcriptional activities.
The enhancer element of the human histo-blood group ABO glycosyltransferase gene has been demonstrated to be located -3.7 kb upstream from the transcription start site and to be composed of four tandem repeats of a 43-bp unit. Recently we identified three different enhancer structures among the allelic A, B, and O glycosyltransferase genes. The enhancer structure with four 43-bp units is present in the B and O genes, but not in the A gene. The corresponding enhancer region of the A gene contains only one 43-bp unit, and within this unit a nucleotide substitution exists when compared with the consensus sequence. Through transient transfection assays, the transcriptional activity of the A-gene enhancer region was demonstrated to be less than 1% of that of the B-gene enhancer. The difference between the transcriptional activities of the two enhancers became more significant when acting in concert with the ABO-gene's native promoter. The different repeat numbers of the 43-bp unit possessed by the two allelic genes were shown to be the main reason for the vast difference in the transcriptional activities between the A-gene and B-gene enhancers.
Yu
L C
LC
Transfusion Medicine Laboratory, Mackay Memorial Hospital, Taipei, Taiwan.
Chang
C Y
CY
Twu
Y C
YC
Lin
M
M
D000017:ABO Blood-Group System / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002240:Carbohydrate Sequence; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D004742:Enhancer Elements, Genetic; D005700:Galactosyltransferases / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics*; D020080:Tandem Repeat Sequences; D014158:Transcription, Genetic
D000017:ABO Blood-Group System; D017931:DNA Primers; D005700:Galactosyltransferases; D017350:N-Acetylgalactosaminyltransferases; C003742:UDPgalactosamine-galactose acetylgalactosaminyltransferase; C023155:blood-group-substance alpha-D-galactosyltransferase