PAX4 and Hyperglycemia: In order to elucidate the mechanism by which β-cells fine tune PAX4 expression without shedding identity and ultimately inducing hyperglycemia we took advantage of a transgenic mouse model expressing both the Gfp and the Cre cDNAs under the transcriptional control of an optimal Pax4 gene promoter sequence (pPax4-Cre-IRES-Egfp mice)23.