<i>Pax6</i> Inactivation in the Adult Pancreas Reveals Ghrelin as Endocrine Cell Maturation Marker

<div><p>The transcription factor <i>Pax6</i> is an important regulator of development and cell differentiation in various organs. Thus, <i>Pax6</i> was shown to promote neural development in the cerebral cortex and spinal cord, and to control pancreatic endocrine cell genesis. However, the role of <i>Pax6</i> in distinct endocrine cells of the adult pancreas has not been addressed. We report the conditional inactivation of <i>Pax6</i> in insulin and glucagon producing cells of the adult mouse pancreas. In the absence of <i>Pax6</i>, beta- and alpha-cells lose their molecular maturation characteristics. Our findings provide strong evidence that <i>Pax6</i> is responsible for the maturation of beta-, and alpha-cells, but not of delta-, and PP-cells. Moreover, lineage-tracing experiments demonstrate that <i>Pax6</i>-deficient beta- and alpha-cells are shunted towards ghrelin marked cells, sustaining the idea that ghrelin may represent a marker for endocrine cell maturation.</p>