The polymorphisms of intron1 sequences of HLA-A and -B

Human leucocyte antigen (HLA) class I antigens are highly polymorphic membrane glycoproteins present on most nucleated cells. The polymorphism region is mainly located in exons 2 and 3 of HLA class I genes, which is flanked by introns 1 and 3. Thus, the sequence information of introns 1 and 3 is important for the genotyping of HLA. However, the information about them has not been extensively reported by now. In this work, the intron 1 sequences of HLA-A and -B of 51 standard genomic DNAs provided by the 13th International Histocompatibility Work Group (IHWG) were cloned and sequenced. The polymorphism of the intron sequences were also analyzed by the software Clustal W 1.82. Some sequences were chosen to compare with the standard sequences published in National Center for Biotechnology Information (NCBI). The comparison showed that all the sequences matched exactly with the standard sequences. The knowledge of intron 1 sequences could be very important not only for developing DNA-based typing strategies for the HLA-A and -B alleles but also for establishing an understanding of the evolutionary mechanisms involved in the polymorphism generation of HLA class I alleles.