Allelic and haplotypic diversity of 5'promoter region of the MICA gene

In this study, the 5'promoter region of MHC class I chain-related gene A (MICA) was investigated in 104 healthy, unrelated Han individuals recruited from northern China, using PCR-sequencing method. Twelve variable sites were detected, which were in very strong linkage disequilibrium with each other. Twelve different MICA 5'promoter haplotypes were identified, among which Promoter-7 predominated (0.5529). Twenty-six extended haplotypes incorporating MICA 5'promoter and MICA exons 2-5 were observed in this population, 9 of which were in significant linkage disequilibrium (LD). Phylogenetic analysis of 5'promoter refined MICA sub-lineage structure previously constructed according to MICA coding and 3'untranslated regions. Ewens-Watterson homozygosity statistics at MICA 5'promoter region were consistent with neutral expectations. None of the five variable sites detected within the minimal promoter of MICA gene was located in the putative binding sites for transcription factor. Our study provided for the first time the sequence information about 5'promoter of MICA gene at a human population level. The data will facilitate the understanding of regulation of MICA gene expression, which represents a promising pathway for immune intervention against cancer, autoimmune disorders and infections.