Telomerase inhibition promotes an initial step of cell differentiation of primate embryonic stem cell

► The initial differentiation step of marmoset embryonic stem cell is studied. ► Undifferentiated embryonic stem cell is cultured in the presence of a telomerase inhibitor. ► The telomerase activity of the embryonic stem cell is decreased due to the telomerase inhibitor. ► The percentage of cells expressing early differentiation markers is higher in the presence of the telomerase inhibitor than in control condition. ► These results suggest that telomerase negatively regulates the initial cell differentiation process. Embryonic stem (ES) cell is well known as a totipotent cell, which is derived from a blastcyst and has potential to differentiate into every kind of somatic cell. ES cell bears self-renewal characteristic as well as differentiation potential. ES cell bears telomerase activity to avoid telomere shortening, which is a characteristic of differentiated somatic cells. As the differentiation of ES cells proceeds, their telomerase activity is losing. However, it has not been convinced whether suppression of the telomerase activity promotes progression of ES cell differentiation. The effect of telomerase inhibitor on the differentiation potential of marmoset ES cell was assessed, counting cells expressing embryonic markers (alkaline phosphatase and TPA-1-60) under existence of a telomerase inhibitor. Telomerase inhibitor showed a promotional effect for the marmoset ES cell differentiation. This result suggests that exogenous inhibition of telomerase activity leads to induction of an early differentiation of primate ES cell.