Figure 4.

Residual INS⁺ cells in Nkx2.2^SDmut/Cre mice lack features characteristic of functionally mature β cells. (A–C) The majority of the remaining INS⁺ cells in Nkx2.2^SDmut/Cre (SDmut/Cre) animals do not exhibit NKX6.1 or PDX1 coexpression at P2 (shown in A). Similarly, MAFA (B) and GLUT2 (C) expression is also not observed. A, panel A′; B, panel B′; and C, panel C′ show higher magnification of Nkx2.2^Cre/+ (WT/Cre) images, while A, panel A′′; B, panel B′′; and C, panel C′′ show higher magnification of Nkx2.2^SDmut/Cre staining. (D) qRT-PCR of Glut2 in P2 pancreata. (E) Schematic summarizing changes in β cell development resulting from mutation of the SD. Data are presented as mean ± SEM. (**) P < 0.01. Scale bars, 50 µm.