GATA-3 is an important transcription factor for regulating human NKG2A gene expression

CD94/NKG2A is an inhibitory receptor expressed by most human NK cells and a subset of T cells that recognizes HLA-E on potential target cells. To study the transcriptional regulation of the human NKG2A gene, we cloned a 3.9-kb genomic fragment that contains a 1.65-kb region upstream of the exon 1, as well as exon 1 (untranslated), intron 1 and exon 2. Using deletion mutants, we identified a region immediately upstream from the most upstream transcriptional initiation site that led to increased transcriptional activity from a luciferase reporter construct in YT-Indy (NKG2A positive) cells relative to Jurkat and K562 (both NKG2A negative) cells. We also localized a DNase I hypersensitivity site to this region. Within this 80-bp segment, we identified two GATA binding sites. Mutation of GATA binding site II (-2302 bp) but not GATA binding site I (-2332 bp) led to decreased transcriptional activity. Pull-down assays revealed that GATA-3 could bind oligonucleotide probes containing the wild type but not a mutated GATA site II. Using chromatin immunoprecipitation assays, we showed that GATA-3 specifically binds to the NKG2A promoter in situ in NKL and primary NK cells, but not in Jurkat T cells. Moreover, coexpression of human GATA-3 with an NKG2A promoter construct in K562 cells led to enhanced promoter activity, and transfection of NKL cells with small interfering RNA specific for GATA-3 reduced NKG2A cell surface expression. Taken together, our data indicate that GATA-3 is an important transcription factor for regulating NKG2A gene expression.