IPAS, MOP7, PASD7, HIF-3A, bHLHe17, Hypoxia-inducible factor 3-alpha, HIF-3-alpha, HIF3-alpha, Basic-helix-loop-helix-PAS protein MOP7, Class E basic helix-loop-helix protein 17, HIF3-alpha-1, Inhibitory PAS domain protein, Member of PAS protein 7, PAS domain-containing protein 7, HIF3A
Involved in adaptive response to hypoxia. Suppresses hypoxia-inducible expression of HIF1A and EPAS1. Binds to core DNA sequence 5-TACGTG-3 within the hypoxia response element (HRE) of target gene promoters. The complex HIF3A-ARNT activates the transcription of reporter genes driven by HRE. Isoform 4 has a dominant-negative function of inactivating HIF1A-mediated transcription. Isoform 4 attenuates the binding of HIF1A to hypoxia-responsive elements (HRE), thus inhibiting HRE-driven transcription. Hypoxia induces down-regulation of isoform 4, leading to activation of HIF1A in hypoxia. Conversely, upon restoring normoxia, the expression of isoform 4 increases and thereby secure an inhibition of HIF1A activity. Isoform 4 may be a negative regulator of hypoxia-inducible gene expression in the kidney and may be involved in renal tumorigenesis. Functions as an inhibitor of angiogenesis in the cornea (By similarity).
