Figure 3.

MafB is produced in a large fraction of adult islet β-cells in βMafBTg mice. A: The MafB transgene is driven by a mouse BAC spanning the region 1–6 control sequences required for β-cell type–specific expression in vivo (31). B: MafB is present in ∼85% of 2-month-old βMafBTg islet β-cells (insulin [INS]) and essentially only α-cells (glucagon [GCG]) in age-matched MafA^fl/fl islets. C: MafB mRNA was increased by 2.5-fold, whereas MafA mRNA levels were unchanged in βMafBTg islets. qPCR signals were normalized to Gapdh expression (n = 5). *P < 0.05. UTR, untranslated region.