HLA-A null allele with a stop codon, HLA-A*0215N, identified in a homozygous state in a healthy adult.
A healthy adult having no serologically detectable HLA class I A locus antigens was identified. The parents of the individual are consanguineous. Results of a family study indicated that the individual is homozygous for the B46-Cw1-DR8.1 haplotype, which was shown to be positively associated with A*0207 in our previous study. The HLA-A null individual is healthy and exhibits no apparent immunological abnormality. Total RNAs extracted from peripheral blood were converted to cDNAs. The reverse transcriptase-polymerase chain reaction (PCR) product, which is of the same size as the normally expressed gene, was easily obtained from the cDNAs with HLA-A locus-specific primers. The nucleotide sequence of this null allele (A*0215N) was the same as that of A*0207 except for a single nucleotide substitution which resulted in a stop codon in exon 4. From its nucleotide sequence, a truncated molecule was expected to be produced; however, the immunoprecipitation study failed to detect the predicted product. Genomic DNAs from 29 unrelated individuals who expressed only one HLA-A antigen with HLA-B46, were analyzed by a PCR-sequence-specific oligonucleotide method. None of the samples possessed this stop codon. Therefore, A*0215N is likely to be a rare allele generated by a single point mutation from A*0207.
Department of Research, Japanese Red Cross Central Blood Center, Tokyo.
Y
Y
Ishikawa
K
K
Tokunaga
H
H
Tanaka
M
M
Nishimura
M
M
Muraoka
Y
Y
Fujii
T
T
Akaza
K
K
Tadokoro
T
T
Juji
D000328:Adult; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D016384:Consensus Sequence; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005805:Genes, MHC Class I; D015234:HLA-A Antigens / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D003062:Codon; D018076:DNA, Complementary; D015234:HLA-A Antigens; D012333:RNA, Messenger