Prmt1 expression in activated and GCBC. (A) Prmt1 transcript levels in three mouse B cell datasets, each normalized to follicular (FO) B cells. Fr, Hardy’s fractions of B cell development; Trans, transitional; MZ, marginal zone; Act., ex vivo-activated mouse splenic B cells (50 µg/ml LPS + 2.5 ng/ml IL-4, 72 h). (B) PRMT transcript levels in activated (as in A) and in GCBC sorted from lymph nodes of immunized mice. Average + SEM RPKM from two biological replicates. (C) Immunohistochemistry for Prmt1, and AID as GC marker, on consecutive spleen sections from immunized mice. Representative of two mice/genotype independently analyzed. Scale bars, 100 µm (top, middle) and 20 µm (bottom). (D) Western blot of PRMT1, aDMA-modified proteins (ASYM26), and actin in extracts of resting and stimulated splenic B cells. MS023 = inhibitor of type I PRMTs. (E) Prmt1 and aDMA-proteins in extracts of resting or activated splenic B cells from two CD21-cre (Ctrl) and two Prmt1F/F CD21-cre (F/F) mice. Revert protein stain as the loading control. (F) Proportion of splenic B cell subpopulations in individual Prmt1F/FCD21-cre (F/F) and CD21-cre (Ctrl) mice (symbols) from three independent experiments, with bars indicating means. MZB cell numbers are presented. P values by unpaired, two-tailed Student’s t test are indicated in the figure. Source data are available for this figure: SourceData F1.