Figure 5

Primary cilia elongation is independent of HIF-2α expression. Loss of primary cilium results in elevated HIF-2α expression and altered response to DMOG. (A)  Antagonism of HIF binding to DNA had no effect on IL-1β-induced elongation. (B) Hsp90 inhibition with 7 nM GA inhibits IL-1-induced increases in HIF-2α expression but has no effect on IL-1β-induced cilia elongation (C). (D) HSP90 inhibition has no effect on ciliary HIF-2α which is still observed by immunofluorescent staining, in the presence of GA. (E) HIF-2α nuclear accumulation appears reduced in cells exhibiting primary cilia sequestering HIF-2α in response to IL-1. Hypomorphic mutation in the gene encoding for IFT88 in ORPK reduces the ability to build a primary cilium. (F) Immunofluorescent labelling of the primary cilium with anti-acetylated α tubulin in WT and ORPK cells. (G) Reduced primary cilia prevalence in ORPK. (H) Western blot analysis of HIF-1α and HIF-2α expression in WT and ORPK. (I) Quantification of western shows increase in HIF-2α expression in ORPK cells. (J) Altered response to DMOG in ORPK with respect to PGE₂ production. ++ represents significant difference (P <0.01) from respective WT group.