Functional analysis of CNOT3 in pancreatic beta cells

Pancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Therefore, defects in pancreatic β-cell function lead to hyperglycemia and diabetes mellitus. Understanding the molecular mechanisms governing β cell function is crucial for development of novel treatment strategies for this disease. The aim of this project was to investigate the role of Cnot3, part of CCR4-NOT complex, major deadenylase complex in mammals, in pancreatic β cell function. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increase of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.