Regulation of the prolyl hydroxylase domain protein 2 (phd2/egln-1) gene: identification of a functional hypoxia-responsive element

摘要: The HIFs (hypoxia-inducible factors) are a family of heterodimeric transcription factors essential for the adaptation cells to reduced oxygen supply. Three human PHDs (prolyl hydroxylase domain proteins, PHD1–PHD3) initiate oxygen-dependent degradation HIF-α-subunits in normoxia. RNA interference directed against PHD2, but not PHD1 or PHD3, is sufficient stabilize HIF-1α Therefore PHD2 regarded as main cellular sensor. itself up-regulated by hypoxia and may thus limit hypoxic signalling. By sequence analysis, we predicted promoter approx. 3.5 kb 5′ translation start codon second located CpG island immediately upstream coding sequence. A consensus HIF-1-binding site that conserved murine phd2 gene was detected island. electrophoretic mobility-shift assay, demonstrated binding HIF-1 putative site. In luciferase reporter vectors, isolated inactive all cell lines tested unless 200 bp were deleted at 3′-end. downstream active induced hypoxia. vectors containing both sequences, activity equal only promoter. transfected with vector promoters, single transcript detectable. This had same length transcripts from only. We conclude transcribed exclusively contains functional hypoxia-responsive, cis-regulatory element. Our results establish direct HIF target gene.