POLYMORPHISM IN THE 5'-TERMINAL REGION OF THE MESSENGER-RNA OF HLA-DQA1 GENE - IDENTIFICATION OF 4 GROUPS OF TRANSCRIPTS AND THEIR ASSOCIATION WITH POLYMORPHISM IN THE ALPHA-1 DOMAIN

Relative to other loci in the MHC, the HLA-DQ locus exhibits an except ional degree of polymorphism of both A1 and B1 genes, particularly in the region coding for alpha and beta chains. Diversification of the as sociation between different alpha and beta molecules either in ris or in trans contributes to the structural diversity of the repertoire of cell-surface class II protein's in the population. In addition, struct ural allelic polymorphisms in the 5' regulatory region of both DQB1 an d DQA1 shows several linkage groups with respect to the allelic coding sequence of the respective genes. We describe here the allelic polymo rphism in the DQA1 mRNA structure located at the 5' untranslated termi nal region. This portion of the mRNA molecule represents, in many gene s, a cis-acting regulatory sequence playing a role in the posttranscri ptional mechanisms by which gene expression can be modulated. Based on detailed transcriptional analysis, we have been able to define at lea st four groups of transcripts in DQA1. The mRNA variability was associ ated with the polymorphism of the second exon of the DQA1 gene, coding for the alpha 1 domain and not with the DNA polymorphism in the 5' re gulatory region. (C) American Society for Histocompatibility and Immun ogenetics, 1997.