(A,B) qRT-PCR (A) and Western blot analysis (B) of islets from Nkx6.1Δ adultβ and control mice at 6 wks for multiple transcription factor genes (A) or Ngn3 (B) (n=3). (C–L) Immunofluorescence staining of pancreata from Nkx6.1 Δadultβ and control mice at 6 wks (C–F) and 14 wks (G–L). Dashed lines represent islet area. Insets are magnifications of selected areas. Arrowhead in (K) points to a cell co-expressing insulin (Ins) and somatostatin (Som). Scale bar = 20 μm. Gluc, glucagon; PP, pancreatic polypeptide; Wk, week. Data are shown as mean ± SEM. *p<0.05, **p<0.01, ***p<0.001.