title: Molecular genetic analysis for the B(3) allele.
abstract: Molecular genetic analysis of 14 samples from unrelated individuals with the B(3) phenotype is reported here. Two different molecular changes in the blood group B gene were observed. One case was demonstrated to possess a 247G --> T mutation, which predicts an Asp83Tyr alteration. The B genes of the other 13 cases were shown to have a G --> A mutation at the +5 nucleotide of intron 3 (intervening sequence 3 [IVS3] + 5G --> A). Reverse transcription polymerase chain reaction analysis showed that the complete exon 1-exon 7 B transcript was absent, and transcripts that skipped exon 3 were instead present in the RNA sample from the B(3) individual with the IVS3 + 5G --> A mutation. The result shows that the IVS3 + 5G --> A mutation destroys the conserved sequence of the splice donor site and leads to the skipping of exon 3 during messenger RNA processing. The B(3) transcript without exon 3 predicts a B-transferase product that lacks 19 amino acids in the N-terminal segment.
authors.affiliation: Transfusion Medicine Laboratory, Department of Medical Research, Mackay Memorial Hospital, Tamshui, Taipei, Taiwan.
authors.forename: Lung-Chih
authors.initials: LC
authors.lastname: Yu
authors.forename: Yuh-Ching
authors.initials: YC
authors.lastname: Twu
authors.forename: Ming-Lun
authors.initials: ML
authors.lastname: Chou
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Chang
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Wu
authors.forename: Marie
authors.initials: M
authors.lastname: Lin
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D017124:Conserved Sequence; D005091:Exons; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000737:chemistry; D010641:Phenotype; D012326:RNA Splicing; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013624:Taiwan
chemical_list: D000017:ABO Blood-Group System; D010446:Peptide Fragments; D012333:RNA, Messenger