Promoter variants of KIR2DL5 add to diversity and may impact gene expression.

Sequencing of polymerase chain reaction (PCR)-amplified genomic DNA encompassing the putative proximal promoter and the coding region was used to identify KIR2DL5 alleles from 77 unrelated Caucasian individuals. PCR and sequencing were used to link each new allele to its neighboring KIR locus to identify 2DL5A or 2DL5B loci. Allele 2DL5A001 was found in 24 of the 37 2DL5 positive individuals; 2DL5B0020101 and 2DL5A0050101 were also observed. Two new alleles, 2DL5B008 and 2DL5B009, contained substitutions altering the amino acid sequence of the leader and transmembrane region, respectively. Two other novel alleles, 2DL5B0020102 and 2DL5A0050102, contained alterations of the 5' upstream region, bringing the number of unique promoter sequences to six. Promoter activity of the alleles was compared using luciferase reporter assays. Our results support those recently published, in which the promoter of 2DL5B0020101 was shown to be more active in vitro compared to 2DL5A*001, and also provide additional information about the transcriptional activity of the promoters of the newly characterized alleles related to two altered transcription factor binding sites.