Fig. 1: KAP1 is a positive regulator of serum-induced transcription.

a Scheme showing dTAG strategy targeting the C-terminus of KAP1 with the dTAG cassette. FKBP-V: degron; 2xHA: two tandem HA tags; P2A: 2A peptide sequence; Puro: Puromycin resistance cassette; BSD: Blasticidin resistance cassette. b Western blot showing dTAG-mediated KAP1 degradation kinetics in HCT116 KAP1^dTAG cells. Blots are representative of two independent experiments. c Scheme showing the experimental design alongside the cell treatments. d RT-qPCR assay highlighting gene expression of one representative IEG (FOS) in DMSO- and dTAG-treated cells during a serum stimulation time course. Data represent mean ± SEM (n = 3 biological replicates, two-sided Student’s t-test comparing DMSO to dTAG at each of the indicated time points). P-values are indicated. Black: DMSO, red: dTAG. e RNA-Seq volcano plot identifying IEGs as upregulated genes upon 30 min of serum stimulation (n = 3 biological replicates, two-sided Likelihood Ratio Test using the Benjamini–Hochberg (BH) multiple comparisons adjustment, false discovery rate [FDR] <0.05). Dots marked red were identified as differentially expressed. f Violin plot showing upregulation of IEGs organized by induction of expression: 2-fold IEGs (n = 236), 4-fold IEGs (n = 69), 8-fold IEGs (n = 34), and 16-fold IEGs (n = 16). Random (n = 236) denotes random genes selected from non-DE genes (n = 10,361). Data represents the Log₂FC value computed from RNA-Seq analysis between the DMSO-S0 and DMSO-S30 condition (generated from 3 biological replicates). The n number represents the number of genes in each cluster plotted. The median is denoted as a dashed black line. g Violin plot showing downregulation of IEGs upon acute KAP1 depletion organized by induction of expression: 2-fold IEGs (n = 236), 4-fold IEGs (n = 69), 8-fold IEGs (n = 34), and 16-fold IEGs (n = 16). Random (n = 236) denotes random genes selected from non-DE genes (n = 10,361). Data represents the Log₂FC value computed from RNA-Seq analysis between the DMSO-S30 and dTAG-S30 conditions (generated from 3 biological replicates). The n number represents the number of genes in each cluster plotted. Median % changes in expression are listed above the violin in each IEGs cluster and Random non-DE genes. The median is also denoted as a dashed black line. h Western blot showing protein expression of two representative IEGs (c-Fos and ATF3) during a serum time course ± dTAG treatment. Blots are representative of three independent experiments. Source data are provided as a Source Data file.