Figure 1.

Map of the Human Major Histocompatibility Complex. The MHC is encoded on chromosome 6 at the 6p21.3 marker. Three classical class I genes HLA-A, C and B and three classical class II genes HLA-DR, DQ and DP are transplantation determinants. A schema for the classical class II gene organization is illustrated for HLA-DPB1: 5’ and 3’ untranslated regions (UTRs; denoted by green boxes); exon 1 (leader); exon 2 and exon 3 (extracellular domains denoted by yellow boxes); exon 4 (transmembrane domain); exon 5 (cytoplasmic tail). Map is not drawn to scale. Chromosome drawing retrieved from the National Library of Medicine.¹