Fig. 4.

β-Cell expression of Kir6.2^CA inhibits β-cell differentiation. A: schematic representation of Tg(−1.2ins:Kir6.2^CA-GFP^TE-ON; LR) used to inducibly express a murine Kir6.2^CA in β-cells. B: RT-PCR of nontransgenic larvae and Tg(−1.2ins:Kir6.2^CA(TE-ON); LR) larvae either without or with doxycycline and tebufenozide induction. Expression of Kir6.2^CA was only observed after induction. C: total free glucose level of 6 dpf Tg(−1.2ins:H2BmCherry) (Kir6.2^CA−) and Tg(−1.2ins:Kir6.2^CA-GFP^TE-ON; LR); Tg(−1.2ins:H2BmCherry) (Kir6.2^CA+) larvae treated with or without doxycycline and tebufenozide. Dox + Tbf-induced Tg(−1.2ins:Kir6.2^CA-GFP^TE-ON; LR); Tg(−1.2ins:H2BmCherry) larvae had significantly increased free glucose levels. D: β-cell number of 6 dpf Tg(−1.2ins:Kir6.2^CA-GFP^TE-ON; LR); Tg(−1.2ins:H2BmCherry) larvae was not significantly changed by induction of Kir6.2^CA expression in unfed larvae. In contrast, the increase in β-cell number was significantly smaller following overnutrition with either 5% egg yolk or 20 mM glucose. All values are means ± SE; n are shown inside of the bars. Groups labeled with different letters are significantly different from each other (P < 0.05).