Figure 4.

Quantitative RT–PCR analysis of gene regulatory network for CSR. (A) Expression of AID mRNA and its transcriptional regulator genes was determined with purified splenic B cells from mice of indicated genotypes stimulated with LPS or LPS plus IL-4 for 2 days. Relative mRNA expression levels were normalized by β-actin mRNA expression and calculated relative to the mRNA expression seen in the wild-type B cells at day 0. Mean data from wild-type (n=2), Bach2^−/− (n=2), Blimp-1^−/− (n=2) and Bach2&Blimp-1 DD (n=3) mice are shown. (B) Expression of Bach2 mRNA in B cells from Blimp-1^−/− mice before and after LPS or LPS plus IL-4 stimulation was measured by quantitative RT–PCR.