The pathological significance of these observations was demonstrated following the generation of β-cell-specific miR-7 overexpressing mice (Tg7) that develop early onset diabetes associated with a striking downregulation of transcripts encoding insulin and other β-cell differentiation markers including Pax6, a direct target of miR-7 [22,24], as well as Pdx1, Mafa, and Slc2a2 (herein referred to as Glut2). This evidence concerns the gene PDX1 and diabetes mellitus.