Alternative titles; symbols
HGNC Approved Gene Symbol: HLA-DOA
Cytogenetic location: 6p21.32 Genomic coordinates (GRCh38): 6:33,004,182-33,009,591 (from NCBI)
Of the alpha chain genes of HLA class II, 5 relate to DR, DQ and DP: DR-alpha, 1 gene; DQ-alpha, 2 genes; DQ-alpha and DX-alpha (HLA-DQA2; 613503), which are greater than 94% related and DP-alpha (which is associated with another gene, DP-alpha-2, a pseudogene.) Spielman et al. (1984) identified a DZ-alpha gene. Trowsdale and Kelly (1985) presented the complete nucleotide sequence of the DZ-alpha gene. Its sequence is about as distantly related to genes in the DP, DQ, and DR subregions as they are to each other. No serologically detectable antigen has been found as a candidate for the DZ-alpha glycoprotein product. DO-beta (142920) might be the DZ-alpha partner. In reviewing the molecular genetics of class II antigens, Trowsdale (1987) pointed out that DX, DO and DZ genes appear to have no protein product. DX-alpha and DX-beta are genes identified first by DNA cloning. All of these genes appear to be intact and capable of functioning in that they do not contain deleterious mutations that would give rise to stop codons or frameshift mutations. All of the splice acceptor or donor signals correspond to consensus signals. Although it is tempting to conclude that DX, DO and DC are incipient pseudogenes with no important functions, several pieces of information tend to contradict this point of view. For one, some of these have been conserved between mouse and man, suggesting that they are functionally important. It may be that these genes are expressed at a significant level in a tissue not yet studied and that they serve a function different from that of DR, DP and DQ.
Spielman, R. S., Lee, J., Bodmer, W. F., Bodmer, J. G., Trowsdale, J. Six HLA-D region alpha-chain genes on human chromosome 6: polymorphisms and associations of DC alpha-related sequences with DR types. Proc. Nat. Acad. Sci. 81: 3461-3465, 1984. [PubMed: 6328517] [Full Text: https://doi.org/10.1073/pnas.81.11.3461]
Trowsdale, J. Genetics and polymorphism: class II antigens. Brit. Med. Bull. 43: 15-36, 1987. [PubMed: 3315095] [Full Text: https://doi.org/10.1093/oxfordjournals.bmb.a072168]
Trowsdale, J., Kelly, A. The human HLA class II alpha chain gene DZ-alpha is distinct from genes in the DP, DQ and DR subregions. EMBO J. 4: 2231-2237, 1985. [PubMed: 3000765] [Full Text: https://doi.org/10.1002/j.1460-2075.1985.tb03919.x]