Figure 4.

Islet β-cell identity marker expression is gained at the expense of α in Gcg-Cre;CAT-Mafa;CAT-Pdx1 islets. Islet β-cell–enriched Glut2 (A) and Nkx6.1 (B) production is specifically induced in Gcg-Cre;CAT-Mafa;CAT-Pdx1;ROSA α-cell lineage–labeled GFP (A) and β-gal (B) cells at the rate of 80% and 36% among labeled cells, respectively. In contrast, the production of α-cell identity (C) Mafb is lost in this α-lineage–marked cell population. The arrows illustrate Glut2-positive, Nkx6.1-positive, or Mafb-negative cells labeled with the lineage marker and presumably expressing Mafa^myc and/or Pdx1^flag. 2W, 2 weeks; INS, insulin. Scale bars: 50 μm.