title: Mutation of the GATA site in the erythroid cell-specific regulatory element of the ABO gene in a Bm subgroup individual.
abstract: BACKGROUND
  The ABO blood group is important in blood transfusion. Recently, an erythroid cell-specific regulatory element has been identified in the first intron of ABO using luciferase reporter assays with K562 cells. The erythroid cell-specific regulatory activity of the element was dependent upon GATA-1 binding. In addition, partial deletion of Intron 1 including the element was observed in genomic DNAs obtained from 111 Bm and ABm individuals, except for one, whereas the deletion was never found among 1005 individuals with the common phenotypes.
  
  
  METHODS
  In this study, further investigation was performed to reveal the underlying mechanism responsible for reduction of B antigen expression in the exceptional Bm individual. Peptide nucleic acid-clamping polymerase chain reaction was carried out to amplify the B-related allele, followed by sequence determination. Electrophoretic mobility assays and promoter assays were performed to examine whether a nucleotide substitution reduced the binding of a transcription factor and induced loss of function of the element.
  
  
  RESULTS
  Sequence determination revealed one point mutation of the GATA motif in the element. The electrophoretic mobility shift assays showed that the mutation abolished the binding of GATA transcription factors, and the promoter assays demonstrated complete loss of enhancer activity of the element.
  
  
  CONCLUSIONS
  These observations suggest that the mutation in the GATA motif of the erythroid-specific regulatory element may diminish the binding of GATA transcription factors and down regulate transcriptional activity of the element on the B allele, leading to reduction of B antigen expression in erythroid lineage cells of the Bm individual.
authors.affiliation: Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan; Cancer Chemotherapy Center and Hematology, University of Occupational and Environmental Health, Fukuoka, Japan; Department of Legal Medicine, Shimane University School of Medicine, Shimane, Japan; Division of Medical Genetics and Biochemistry, Faculty of Medicine, University of Fukui, Fukui, Japan; Japanese Red Cross Tokyo Blood Center, Tokyo, Japan; Japanese Red Cross Central Blood Institute, Tokyo, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Nakajima
authors.forename: Rie
authors.initials: R
authors.lastname: Sano
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Rieko
authors.initials: R
authors.lastname: Kubo
authors.forename: Keiko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kominato
authors.forename: Junichi
authors.initials: J
authors.lastname: Tsukada
authors.forename: Haruo
authors.initials: H
authors.lastname: Takeshita
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Yasuda
authors.forename: Makoto
authors.initials: M
authors.lastname: Uchikawa
authors.forename: Kazumi
authors.initials: K
authors.lastname: Isa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ogasawara
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics; D015331:Cohort Studies; D041905:Erythroid Cells / Q000378:metabolism*; D050982:GATA1 Transcription Factor / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D020014:K562 Cells; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D017354:Point Mutation; D020218:Response Elements / Q000235:genetics*
chemical_list: D000017:ABO Blood-Group System; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human