Fig. 6
From: Environmental sensing by mature B cells is controlled by the transcription factors PU.1 and SpiB
PU.1 and SpiB maintain expression of multiple BCR components. a Gene expression (from Fig. 5) for the indicated genotype is plotted as the mean fold change (log2, from 2 experiments) relative to the expression in the control genotype. *Indicates genes that are DE relative to controls (defined as log2 fold change >0.6-fold, log2 RPKM (reads per kilobase of exon model per million mapped reads) >0, P < 0.15). b PU.1 ChIPseq identifies promoter-binding sites for PU.1 in many components of the BCR signaling pathway. Gene structures are shown below. Gene names in a, b with PU.1 peaks (P < 10−6) are indicated in red. c Lysates were generated from activated B cells (cultured for 48 h in CD40 L + IL-4) of the indicated genotype. Western blotting was performed for the indicated proteins. Actin serves as a control for protein loading. Data in b, c are representative of two experiments each. d Loss of PU.1 and SpiB leads to decreased viability in response to BCR signaling. Resting lymph node B cells from mice of the indicated genotype were labeled with CTV and cultured in the presence of anti-IgM + IL-4 for 3d before flow cytometric analysis. The number of live cells is plotted for each genotype examined. Data are the mean ± s.d. for three independent experiments. P-values compare the indicated samples (two tailed t-test). ****P < 0.0001. e Resting B cells of the indicated genotype were cultured with CD40 L + IL-4 for 48 h before being washed and rested for one hour. Cells were then loaded with Indo-1 AM before basal fluorescence was measured for 30 s. Anti-IgM was then added and fluorescence changes recorded for an additional 2.5 min. Results are presented as arbitrary units of changes in fluorescence ratio over time. Data are representative of two experiments
