Fig. 7: The activation of TCF3, TCF4 and IRF4 downstream of p38α in PC differentiation.

a Cultured p38α^−/− B cells were transduced with retroviruses encoding p38α or p38α kinase-dead mutations (K53M or T180A/Y182F) (GFP⁺) and luciferase reporter harboring TCF3, TCF4 or IRF4 binding sites in Prdm1 enhance region at day 2, and luciferase activity in retrovirus-infected B cells (CD19⁺GFP⁺) was analyzed at day 8 in iPC culture (n = 3 per group). b p38^−/− 293 A cells were transfected with indicated plasmids, and the luciferase activity of IRF4 mutants was analyzed 24 h after transfection. Immunoblot analysis of p38α, p-p38α, IRF4 and Actin in p38^−/− 293 A cells transfected with indicated plasmids (n = 3 per group). c Cultured Irf4^−/− B cells were transduced with retroviruses encoding IRF4 or IRF4 mutants (T267A, T268A, T269A) at day 2, iPCs in retrovirally transduced B cells (CD19⁺GFP⁺CD138⁺) 6 days after transduction were analyzed by flow cytometry (n = 5 per group), and protein levels of IRF4, IgG H-chain, BLIMP1 and Actin were analyzed by immunoblot. Data were representative of at least three independent experiments. Each symbol represents a representative sample. Small horizontal lines indicate the mean (±s.d.). Data were analyzed by two-tailed unpaired t-tests. Source data are provided as a Source Data file.