Major histocompatibility complex, class II, DQ alpha 1, also known as HLA-DQA1, is a human
gene present on short arm of
chromosome 6 (6p21.3) and also denotes the genetic
locus which contains this gene.[5] The
protein encoded by this gene is one of two proteins that are required to form the
DQ heterodimer, a cell surface
receptor essential to the function of the
immune system.
Function
HLA-DQA1 belongs to the
HLA class II alpha chain
paralogues. This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in
antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages).[5]
Gene structure and polymorphisms
The alpha chain contains 5
exons. Exon one encodes the leader peptide,
exons 2 and 3 encode the two extracellular
protein domains, exon 4 encodes the
transmembrane domain and the
cytoplasmic tail. Within the DQ molecule both the alpha chain and the beta chain contain the
polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules. Typing for these polymorphisms is routinely done for
bone marrow transplantation.[5][6]
Alleles
DQ1
There are four commonly encountered DQA1 alleles: DQA1*0101, *0102, *0103, *0104. These alleles are always found in haplotypes with HLA-DQB1*05 (
DQ5) and HLA-DQB1*06 (
DQ6). DQ1 is a serotype, rare among serotypes for human class II antigens, in that the antibodies to DQ1 react to the alpha chain of HLA DQ, these DQA1 allele gene products.
See haplotype table in
HLA-DQ. Unbolded are rare haplotypes
Link to haplotypes can be followed by DQB1 alleles
Other
The other DQA1 alleles have no defined serotype. There are 5 groups, DQA1*02, *03, *04, *05, *06. DQA1 within these groups are either invariant or produce the same α-chain subunit. DQA1*02 and DQA1*06 contain only one allele. DQA1*03 has three alleles which each produce nearly identical α3. For DQA1*05, the DQA1*0501 and DQA1*0505 produce identical α5. Other DQA1*05 exist that produce variant α5var, but these are rare.
Piatier-Tonneau D, Gastinel LN, Amblard F, et al. (1991). "Interaction of CD4 with HLA class II antigens and HIV gp120". Immunogenetics. 34 (2): 121–8.
doi:
10.1007/BF00211424.
PMID1869305.
S2CID10116507.
Turco E, Care A, Compagnone-Post P, et al. (1987). "Allelic forms of the alpha- and beta-chain genes encoding DQw1-positive heterodimers". Immunogenetics. 26 (4–5): 282–90.
doi:
10.1007/BF00346523.
PMID2888727.
S2CID44734030.
Lock CB, So AK, Welsh KI, et al. (1988). "MHC class II sequences of an HLA-DR2 narcoleptic". Immunogenetics. 27 (6): 449–55.
doi:
10.1007/BF00364432.
PMID3259543.
S2CID2338823.
Horn GT, Bugawan TL, Long CM, et al. (1988). "Sequence analysis of HLA class II genes from insulin-dependent diabetic individuals". Hum. Immunol. 21 (4): 249–63.
doi:
10.1016/0198-8859(88)90034-1.
PMID3372263.
Andrieu JM, Even P, Venet A (1986). "AIDS and related syndromes as a viral-induced autoimmune disease of the immune system: an anti-MHC II disorder. Therapeutic implications". AIDS Research. 2 (3): 163–74.
doi:
10.1089/aid.1.1986.2.163.
PMID3489470.
Major histocompatibility complex, class II, DQ alpha 1, also known as HLA-DQA1, is a human
gene present on short arm of
chromosome 6 (6p21.3) and also denotes the genetic
locus which contains this gene.[5] The
protein encoded by this gene is one of two proteins that are required to form the
DQ heterodimer, a cell surface
receptor essential to the function of the
immune system.
Function
HLA-DQA1 belongs to the
HLA class II alpha chain
paralogues. This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in
antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages).[5]
Gene structure and polymorphisms
The alpha chain contains 5
exons. Exon one encodes the leader peptide,
exons 2 and 3 encode the two extracellular
protein domains, exon 4 encodes the
transmembrane domain and the
cytoplasmic tail. Within the DQ molecule both the alpha chain and the beta chain contain the
polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules. Typing for these polymorphisms is routinely done for
bone marrow transplantation.[5][6]
Alleles
DQ1
There are four commonly encountered DQA1 alleles: DQA1*0101, *0102, *0103, *0104. These alleles are always found in haplotypes with HLA-DQB1*05 (
DQ5) and HLA-DQB1*06 (
DQ6). DQ1 is a serotype, rare among serotypes for human class II antigens, in that the antibodies to DQ1 react to the alpha chain of HLA DQ, these DQA1 allele gene products.
See haplotype table in
HLA-DQ. Unbolded are rare haplotypes
Link to haplotypes can be followed by DQB1 alleles
Other
The other DQA1 alleles have no defined serotype. There are 5 groups, DQA1*02, *03, *04, *05, *06. DQA1 within these groups are either invariant or produce the same α-chain subunit. DQA1*02 and DQA1*06 contain only one allele. DQA1*03 has three alleles which each produce nearly identical α3. For DQA1*05, the DQA1*0501 and DQA1*0505 produce identical α5. Other DQA1*05 exist that produce variant α5var, but these are rare.
Piatier-Tonneau D, Gastinel LN, Amblard F, et al. (1991). "Interaction of CD4 with HLA class II antigens and HIV gp120". Immunogenetics. 34 (2): 121–8.
doi:
10.1007/BF00211424.
PMID1869305.
S2CID10116507.
Turco E, Care A, Compagnone-Post P, et al. (1987). "Allelic forms of the alpha- and beta-chain genes encoding DQw1-positive heterodimers". Immunogenetics. 26 (4–5): 282–90.
doi:
10.1007/BF00346523.
PMID2888727.
S2CID44734030.
Lock CB, So AK, Welsh KI, et al. (1988). "MHC class II sequences of an HLA-DR2 narcoleptic". Immunogenetics. 27 (6): 449–55.
doi:
10.1007/BF00364432.
PMID3259543.
S2CID2338823.
Horn GT, Bugawan TL, Long CM, et al. (1988). "Sequence analysis of HLA class II genes from insulin-dependent diabetic individuals". Hum. Immunol. 21 (4): 249–63.
doi:
10.1016/0198-8859(88)90034-1.
PMID3372263.
Andrieu JM, Even P, Venet A (1986). "AIDS and related syndromes as a viral-induced autoimmune disease of the immune system: an anti-MHC II disorder. Therapeutic implications". AIDS Research. 2 (3): 163–74.
doi:
10.1089/aid.1.1986.2.163.
PMID3489470.