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Major histocompatibility complex, class II, DR beta 1
Structure of HLA-DRB1 (green) complexed with HLA-DRA (cyan) and a fragment of HLA-A (magenta) based on the PDB: 1AQD​ coordinates
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols HLA-DRB1 ; DRB1; DRw10; HLA-DR1B; HLA-DRB; SS1
External IDs OMIM142857 MGI95901 HomoloGene136635 GeneCards: HLA-DRB1 Gene
RNA expression pattern
PBB GE HLA-DRB3 209312 x at tn.png
More reference expression data
Species Human Mouse
Entrez 3123 14969
Ensembl ENSG00000196126 ENSMUSG00000060586
UniProt P01911 O78196
RefSeq (mRNA) NM_001243965 NM_010382
RefSeq (protein) NP_001230894 NP_034512
Location (UCSC) Chr 6:
32.55 – 32.59 Mb
Chr 17:
34.31 – 34.32 Mb
PubMed search [1] [2]

HLA class II histocompatibility antigen, DRB1-9 beta chain is a protein that in humans is encoded by the HLA-DRB1 gene.[1] DRB1 encodes the most prevalent beta subunit of HLA-DR. It is associated with an increased incidence of rheumatoid arthritis.


The protein encoded by this gene belongs to the HLA class II beta chain paralogues. The class II molecule is a heterodimer consisting of an alpha (DRA) and a beta chain (DRB), 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).[1]

Gene structure and polymorphisms[edit]

The beta chain is approximately 26-28 kDa. It is encoded by 6 exons, exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, exon 4 encodes the transmembrane domain and exon 5 encodes the cytoplasmic tail. Within the DR molecule the beta chain contains all the polymorphisms specifying the peptide binding specificities. Hundreds of DRB1 alleles have been described and typing for these polymorphisms is routinely done for bone marrow and kidney transplantation.[1]

Gene expression[edit]

DRB1 is expressed at a level five times higher than its paralogues DRB3, DRB4 and DRB5. DRB1 is present in all individuals. Allelic variants of DRB1 are linked with either none or one of the genes DRB3, DRB4 and DRB5. There are 4 related pseudogenes: DRB2, DRB6, DRB7, DRB8 and DRB9.[1]

See also[edit]


Further reading[edit]

  • Turesson C, Matteson EL (2006). "Genetics of rheumatoid arthritis.". Mayo Clin. Proc. 81 (1): 94–101. doi:10.4065/81.1.94. PMID 16438485. 
  • Ahmad T, Marshall SE, Jewell D (2006). "Genetics of inflammatory bowel disease: the role of the HLA complex.". World J. Gastroenterol. 12 (23): 3628–35. PMID 16773677. 
  • Schmidt H, Williamson D, Ashley-Koch A (2007). "HLA-DR15 haplotype and multiple sclerosis: a HuGE review.". Am. J. Epidemiol. 165 (10): 1097–109. doi:10.1093/aje/kwk118. PMID 17329717.