Glucagon gene expression in the endocrine pancreas: the role of the transcription factor Pax6 in α‐cell differentiation, glucagon biosynthesis and secretion

Y Gosmain, C Cheyssac… - Diabetes, Obesity …, 2011 - Wiley Online Library
Y Gosmain, C Cheyssac, M Heddad Masson, C Dibner, J Philippe
Diabetes, Obesity and Metabolism, 2011Wiley Online Library
The glucagon gene is expressed in α‐cells of the pancreas, L cells of the intestine and the
hypothalamus. The determinants of the α‐cell‐specific expression of the glucagon gene are
not fully characterized, although Arx, Pax6 and Foxa2 are critical for α‐cell differentiation
and glucagon gene expression; in addition, the absence of the β‐cell‐specific transcription
factors Pdx1, Pax4 and Nkx6. 1 may allow for the glucagon gene to be expressed. Pax6,
along with cMaf and MafB, binds to the DNA control element G1 which confers α‐cell …
The glucagon gene is expressed in α‐cells of the pancreas, L cells of the intestine and the hypothalamus. The determinants of the α‐cell‐specific expression of the glucagon gene are not fully characterized, although Arx, Pax6 and Foxa2 are critical for α‐cell differentiation and glucagon gene expression; in addition, the absence of the β‐cell‐specific transcription factors Pdx1, Pax4 and Nkx6.1 may allow for the glucagon gene to be expressed. Pax6, along with cMaf and MafB, binds to the DNA control element G1 which confers α‐cell specificity to the promoter and to G3 and potently activates glucagon gene transcription. In addition, to its direct role on the transcription of the glucagon gene, Pax6 controls several transcription factors involved in the activation of the glucagon gene such as cMaf, MafB and NeuroD1/Beta2 as well as different steps of glucagon biosynthesis and secretion. We conclude that Pax6 independently of Arx and Foxa2 is critical for α‐cell function by coordinating glucagon gene expression as well as glucagon biosynthesis and secretion.
Wiley Online Library