Fig 1: The DUX4-CTD decreases STAT1 occupancy at interferon-stimulated gene (ISG) promoters and blocks Pol-II recruitment.(A, left four panels) Chromatin immunoprecipitation using anti-STAT1 or IgG from MB135-iDUX4-CTD cells untreated, IFN?-treated, or IFN? and doxycycline treated. Ab1: 50:50 mix of STAT1 antibodies Abcam ab239360 and ab234400; Ab2: Abcam ab109320. ChIP-qPCR analysis relative to a standard curve constructed from purified input DNA was used to determine the quantity of DNA per IP sample, which was then graphed as a % of input. Data represent the mean ± SD of two biological replicates with three technical replicates each (unpaired t-test; ****p<0.0001, ***p<0.001, **p<0.01, *p<0.05, ns p>0.05). (A, right panel) RT-qPCR of RNA from cells used for STAT1 ChIP showing induction of interferon-stimulated genes (ISGs) by IFN? and suppression by DUX4-CTD. (B) CUT&Tag data showing the intensity of Pol-II signal across a 2000 bp window centered on the TSS of ISGs (left) or IFN?-unchanged genes (right) in untreated, IFN?-treated, or IFN? and doxycycline-treated MB135-iDUX4-CTD cells.