Journal: The Journal of cell biology
Article Title: DUX4-induced HSATII RNA accumulation drives protein aggregation impacting RNA processing pathways
doi: 10.1083/jcb.202501129
Figure Lengend Snippet: ( A ) Immunofluorescence of EU-RNA aggregates (gray) in iDUX4 cells that were left untreated (−DOX) or pulsed for 4-hours using 1ug/mL doxycycline (+DOX) and then incubated with 0.1mM 5-ethynyluridine (+EU) for 16-hours prior to washout and fixed at 24-hour time points (24–96 hours). Control cells were uninduced (−DOX) iDUX4 cells incubated with EU and fixed at either 24 hours or 96 hours or without EU and fixed at 24 hours. Scale bar = 20μm. Images are representative of two independent experimental replicates performed. ( B ) Percent of cells with intranuclear EU-RNA aggregates in −DOX or +DOX iDUX4 cells labeled with EU for 16-hours at 24-hour time points. EU-RNA aggregates are present within +DOX iDUX4 cells from 24-hour to 72-hour time points. N=2 experimental replicates. Minimum 200 nuclei per experiment. Data represent means ± standard deviation (SD). Statistical differences between groups were analyzed employing one-way ANOVA Dunnett’s multiple comparisons test between each group and a control (−DOX+EU 24-hour time point). ( C ) Enrichment of RPL27 or HSATII RNA in isolated EU-RNA from −DOX or +DOX iDUX4 cells incubated with EU for 16-hours or +DOX iDUX4 cells with no EU treatment, all harvested at the 48-hour time point. Housekeeping gene RPL27 is used as a control. N=3. A total of four independent experimental replicates were performed. Data represent means ± SD. ( D ) Quantitative RT-PCR of HSATII expression (2 −DCt ) in −DOX or +DOX iDUX4 cells treated with EU for 16-hours or +DOX iDUX4 cells with no EU treatment, all harvested at the 48-hour time point. EU-treatment does not impact HSATII RNA expression. N=3. A total of four independent experimental replicates were performed. Data represent means ± SD. Statistical differences between groups were analyzed employing one-way ANOVA Dunnett’s multiple comparisons test between each group and a control (−DOX+EU). ( E ) Enrichment of RPL27 or HSATII RNA in isolated EU-RNA from −DOX or +DOX iDUX4 cells incubated with EU for 16-hours and harvested at 24-hour time points from 48-hours to 96-hours. Housekeeping gene RPL27 is used as a control. N=3. A total of three independent experimental replicates were performed. Data represent means ± SD. ( F ) Combined immunofluorescence and HSATII RNA-fluorescence in situ hybridization (RNA-FISH) of HSATII RNA (green) and EU-RNA (magenta) in +DOX+EU iDUX4 cells fixed at 48-hour time point. Scale bar = 20μm. Images are representative of three independent experimental replicates performed. ( G ) Percent of cells with intranuclear EU-RNA aggregates only (“EU”), HSATII RNA aggregates only (“HSATII”) or both EU-RNA/ HSATII RNA aggregates (“both”) in +DOX+EU iDUX4 cells fixed at the 48-hour time point. N=3 experimental replicates. Minimum 200 nuclei per experiment. Data represent means ± SD. ( H ) Combined immunofluorescence and HSATII RNA-FISH of HSATII RNA (green) and EU-RNA (magenta) in control depleted (“CTRL KD”) or HSATII RNA-depleted (“HSATII KD”) +DOX+EU iDUX4 cells fixed at 48-hour time point. Scale bar = 20μm. Images are representative of two independent experimental replicates performed. ( I ) Percent of cells with intranuclear RNA aggregates: EU only, HSATII only or both in CTRL KD or HSATII KD +DOX+EU iDUX4 cells fixed at the 48-hour time point. N=2 experimental replicates. Minimum 200 nuclei per experiment. Data represent means ± SD. Statistical differences between groups were analyzed employing two-way ANOVA Šídák’s multiple comparisons test between CTRL KD and HSATII KD within each group (EU, HSATII, both). Fig 1G and 1L : The frequency of cells containing RNA aggregates exhibits some variability across the population. This variability could be due to the robustness and induction efficiency of doxycycline treatment. ( J ) Combined immunofluorescence (IF) of EU-RNA (green) and Fibrillarin (magenta) in −DOX+EU or +DOX+EU iDUX4 cells fixed at 48-hour time point or combined immunofluorescence and HSATII RNA-FISH of HSATII RNA (green) and fibrillarin (magenta) in −DOX and +DOX iDUX4 cells fixed at 24-hours. Scale bar = 20μm. Arrows indicate nuclei with disrupted nucleolar staining. Images are representative of two independent experimental replicates performed. ( K ) Immunofluorescence (IF) of EU-RNA (green) and nucleophosmin-1 (NPM1) (magenta) in −DOX+EU or +DOX+EU iDUX4 cells fixed at 48-hour time point or combined immunofluorescence and HSATII RNA-FISH of HSATII RNA (green) and NPM1 (magenta) in −DOX and +DOX iDUX4 cells fixed at 24-hours. Scale bar = 20μm. Arrows indicate nuclei with disrupted nucleolar staining. Images are representative of two independent experimental replicates performed. ( L ) Percent of cells with nucleolar disruption present in cells with intranuclear RNA aggregates. N=2 experimental replicates. Minimum 300 nuclei per experiment.
Article Snippet: RNA was isolated in RNA elution buffer (10 mM EDTA, pH 8.0, 95% formamide (ThermoFisher Scientific)) and incubated at 95°C for 5 minutes at 1,000xg.
Techniques: Immunofluorescence, Incubation, Control, Labeling, Standard Deviation, Isolation, Quantitative RT-PCR, Expressing, RNA Expression, Fluorescence, In Situ Hybridization, Staining, Disruption