DIFFERENTIAL EXPRESSION OF HLA-DQB1 ALLELES IN A HETEROZYGOUS CELL-LINE

Regulation of HLA class II transcription is complex, with both locus-s pecific and allele-specific polymorphisms associated with consensus re gulatory region promoter elements. In order to evaluate the potential function of allele-specific elements, HLA-DQB1 transcripts and in vivo footprinting of the DQB1 promoter were studied in human cell lines in ducible for HLA class II expression. In the heterozygous melanoma cell line Me9229/18, differential expression was observed for two DQB1 all eles. This variation was reflected in both steady-state and inducible transcripts, although methylation patterns of the promoter elements we re similar for both alleles. This in vivo allelic difference expressio n, which correlates with previous studies of in vitro reporter gene tr anscription, indicates the potential for functionally important differ ences in tissue-specific and inducible expression attributable to prom oter region polymorphism in HLA genes.