10.6084/m9.figshare.3823734.v1 S. E. Taylor J. Bagnall D. Mason R. Levy D. G. Fernig V. SEE Supplemental Movie 1: Time-lapse imaging in hypoxia of a single HeLa cell ectopically expressing EGFP-HIF-2α. from Differential sub-nuclear distribution of hypoxia-inducible factors (HIF)-1 and -2 alpha impacts on their stability and mobility 2016 The Royal Society hypoxia hypoxia-inducible factor HIF-2α nuclear speckles confocal microscopy fluorescence recovery after photo-bleaching 2016-09-13 07:42:32 article https://rs.figshare.com/articles/Supplemental_Movie_1_Time-lapse_imaging_in_hypoxia_of_a_single_HeLa_cell_ectopically_expressing_EGFP-HIF-2_from_Differential_sub-nuclear_distribution_of_hypoxia-inducible_factors_HIF_-1_and_-2_alpha_impacts_on_their_stability_and_mobility/3823734 Cellular adaptation to hypoxia occurs via a complex program of gene expression mediated by the hypoxia-inducible factor (HIF). The oxygen labile alpha subunits, HIF-1α/-2α, form a heterodimeric transcription factor with HIF-1β and modulate gene expression. HIF-1α and HIF-2α possess similar domain structure and bind to the same consensus sequence. However, they have different oxygen-dependent stability and activate distinct genes. To better understand these differences, we used fluorescent microscopy to determine precise localization and dynamics. We observed a homogeneous distribution of HIF-1α in the nucleus, while HIF-2α localized into speckles. We demonstrated that the number, size and mobility of HIF-2α speckles were independent of cellular oxygenation and that HIF-2α molecules were capable of exchanging between the speckles and nucleoplasm in an oxygen-independent manner. The concentration of HIF-2α into speckles may explain its increased stability compared with HIF-1α and its slower mobility may offer a mechanism for gene specificity.