Chronic administration of pegIFNα preferentially activates p53 and apoptotic transcriptional programs in Jak2V617F LT-HSCs compared to WT. (A) Experimental schematic for determining the effect of chronic pegIFNα administration (600ng, weekly) on transcript expression in Jak2^fl-V617F/+;Tg(E2A-cre) (VF, CD45.1^–/CD45.2⁺) or Jak2^+/+ (WT, CD45.1⁺/CD45.2^–) LT-HSCs isolated from the bone marrow (BM) of chimeric mice treated with either vehicle (V, n = 6) or pegIFNα (P, n = 6) (B-E). (B) Gene set enrichment analysis (GSEA) comparing transcript expression in WT LT-HSCs isolated from chimeric mice treated with pegIFNα (WT-P, n = 6) with that in WT LT-HSCs treated with vehicle (WT-V, n = 6). (C) GSEA comparing transcript expression in WT LT-HSCs (WT-P, n = 6) vs VF LT-HSCs (VF-P, n = 6) isolated from chimeric mice treated with pegIFNα. (D) Normalized read count for Trp53 and the p53 target genes, Cdkn1a (p21), Bbc3 (Puma), and Pmaip1 (Noxa), as determined by RNA sequencing of WT or VF LT-HSCs isolated from chimeric mice treated with either vehicle (V) or pegIFNα (P)(n = 6/group). (E) Normalized read count for transcripts encoding prosurvival proteins, Bcl2, Bcl-xL (Bcl2l1), and Mcl-1, as determined by RNA sequencing of WT or VF LT-HSCs isolated from chimeric mice treated with either V or pegIFNα (P)(n = 6/group). Individual data points represent data generated from independent recipient mice. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001∗∗∗; ∗∗∗∗P < .0001. FDR, false discovery rate; mRNA, messenger RNA; NES, normalized enrichment score; WBM, whole bone marrow.