Fig 1: EZH2 is required to enable Rb phosphorylation in GC B cells. a Formalin fixed paraffin embedded splenic tissue from mice shown in Fig. 1 was stained for phospho Rb Ser780 and PNA. One representative picture of three spleens analyzed per genotype group is shown. b, c Quantification of phospho Rb Ser780 staining from a (n = 3 spleens per group). b “pRb positive per GC area/total spleen area” is the quantified area of each individual GC divided by the total area of the spleen section. c “pRb positive in total GC area/total spleen area” is the sum of all GC quantified areas in a certain section divided by the total area of that spleen section. Values are shown as mean of triplicates ± SEM. t test, **P < 0.01. d Immunoblotting of whole cell lysates from naive B cells (FAS- GL7- IgD+ B220+) and GC B cells (FAS+ GL7+ B220+) sorted from 2 Cdkn1a -/-, 2 Ezh2 fl/fl;C?1-cre;Cdkn1a -/- double knockout (DKO) and 2 Ezh2 fl/fl control mice immunized with SRBC for 10 days. GAPDH was used as loading control. The faint EZH2 band in DKO GC B cells is due to the few residual GC B cells that were still EZH2 positive, consistent with incomplete CRE-mediated excision of Ezh2. Numbers on the left indicate molecular weight in kDa. See Supplementary Fig. 6A for uncropped scans of the western blots