Molecular genetic analysis of the ABO blood group system: 3. A(X) and B(A) alleles.
We have employed a PCR approach to determine the nucleotide sequences of the coding region in the last two coding exons of the histo-blood group ABO genes from one A(X) and one B(A) individual. Compared with A1 alleles, the (A(X)) allele has a single nucleotide substitution (T-->A at nucleotide 646) resulting in an amino acid substitution (phenylalanine-->isoleucine at amino acid 216). Compared with B alleles, the B(A) allele has two nucleotide substitutions (T-->C at nt. 657 and A-->G at nt. 703) resulting in an amino acid substitution (serine-->glycine at aa. 235). The amino acid substitution resulting from this B(A) allele is located at the second of the four amino acid substitutions which discriminate human A and B transferases, and the amino acid residue (glycine) is identical to that of A transferase suggesting the involvement of this amino acid or its surrounding area for the recognition and/or binding of the donor nucleotide sugars.
Yamamoto
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F
Department of Molecular Biology, Biomembrane Institute, Seattle, WA 98119.
McNeill
P D
PD
Yamamoto
M
M
Hakomori
S
S
Harris
T
T
D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D001483:Base Sequence; D015894:Genome, Human; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D010641:Phenotype
D000017:ABO Blood-Group System