HLA-J, a second inactivated class I HLA gene related to HLA-G and HLA-A. Implications for the evolution of the HLA-A-related genes.
Ragoussis and co-workers (Genomics 4:301) previously described a class I HLA gene (now designated HLA-J) that maps to within 50 kb of HLA-A. The nucleotide sequences of three HLA-J alleles are reported here. Comparison of the nucleotide sequences of HLA-J alleles shows this gene is more related to HLA-G, A, and H than to HLA-B, C, E, and F. All four alleles of HLA-J are pseudogenes because of deleterious mutations that produce translation termination either in exon 2 or exon 4. Apart from these mutations, the predicted proteins have structures similar to those of HLA-A, B, and C molecules. There is, however, little polymorphism at HLA-J and none at functional positions of the Ag-recognition site. The polymorphism is less than found for HLA-H another HLA-A-related pseudogene. HLA-J appears, like HLA-H, to be an inactivated gene that result from duplication of an Ag-presenting locus related to HLA-A. Nucleotide sequence comparisons show that the HLA-A, H, J, and G genes form a well defined group of "HLA-A-related" loci. Evolutionary relationships as assessed by construction of trees suggest the four modern loci: HLA-A, G, H, and J were formed by successive duplications from a common ancestral gene. In this scheme one intermediate locus gave rise to HLA-A and H, the other to HLA-G and J.
Messer
G
G
Institut für Immunologie, Universität München, F.R.G.
Zemmour
J
J
Orr
H T
HT
Parham
P
P
Weiss
E H
EH
Girdlestone
J
J
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D005075:Biological Evolution; D002872:Chromosome Deletion; D016384:Consensus Sequence; D004742:Enhancer Elements, Genetic; D005091:Exons; D005805:Genes, MHC Class I; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011544:Pseudogenes; D015183:Restriction Mapping; D016415:Sequence Alignment
D015395:Histocompatibility Antigens Class I