Fig. 7: p53 suppresses M2-driven B cell proliferation.

a, b Quantification of p53^-/- or p53^+/+ B cells undergoing DNA replication after transduction with M2 or M2.Stop retroviruses. Cells were pulsed with 10 mM EdU for 4 h prior to harvest at 50 h post-transduction. Cells in (b) were treated with Src-family inhibitor PP2 (10 μM) or controls (DMSO at 1:1000, PP3 at 10 μM) 24 h post-transduction. EdU incorporation in newly synthesized DNA was labeled by Click chemistry. EdU⁺ transduced B cells (gated on ZsGreen⁺ cells) were detected by flow cytometry. Data represent means +/− SEM. Two-tailed Student’s t test, ns - not significant, *p < 0.05, ** p  <  0.01. The experiment was performed in technical triplicate. Representative flow cytometry plots and additional controls are shown in Supplementary Fig. 12. c–f RNA-seq was performed 4 days after transduction of p53^-/- or p53^+/+ B cells with M2 or M2.Stop retroviruses to evaluate changes in transcription. Data in (c, d) show gene set enrichment analysis (GSEA) and hallmark gene z-score heatmaps comparing M2 to M2.Stop for the hallmark p53 gene set. Data in (e, f) show the hallmark E2F gene set. Statistical scores are inset into the top right of analysis images. NES, normalized enrichment score. q-val, FDR-adjusted p-value. d, f z-score heatmaps show average expression data for M2 or M2.Stop expressing primary B cells. The genes presented were derived from GSEA and DEseq2 analysis of all genes with significant expression changes where the expression level increased from M2 to M2.Stop at least 1.5-fold and decrease from M2 to M2.Stop at least 1.5-fold. A table of hallmark gene sets with significant changes caused by M2 are shown in Supplementary Fig. 14.