Expression of neuronal traits in pancreatic beta cells - Implication of neuron-restrictive silencing factor/repressor element silencing transcription factor, a neuron-restrictive silencer

Pancreatic beta cells (insulin-producing cells) and neuronal cells share a large number of similarities. Here, we investigate whether the same mechanisms could control the expression of neuronal genes in both neurons and insulin-producing cells. For that purpose, we tested the role of the transcriptional repressor neuron-restrictive silencing factor/repressor element silencing transciption factor (NRSF/REST) in the expression of a battery of neuronal genes in insulin-producing cells. NRSF/REST is a negative regulator of the neuronal fate. It is known to silence neuronal-specific genes in non-neuronal cells. We demonstrate that, as in the case of the neuronal pheochromocytoma cell line PC12, mRNA coding for NRSF/REST is absent from the insulinoma cell line INS-1 and from three other insulin and glucagon producing cell lines. NRSF/REST activity is also absent from insulin-producing cell lines. Transient expression of REST in insulin-producing cell lines is sufficient to silence a reporter gene containing a NRSF/REST binding site, demonstrating the role of NRSF/REST in the expression of neuronal markers in insulin-producing cells. Finally, by searching for the expression of NRSF/REST-regulated genes in insulin-producing cells, we increased the list of the genes expressed in both neurons and insulin-producing cells.