NEUROD1 and infection: At 3days after infection, selective increases in the mRNA levels of insulin I (Ins1) and insulin II (Ins2) were observed in the cells that had been infected with a triple combination of adenovirus (Pdx1 and MafA, with either Ngn3 or NeuroD1) in a semiquantitative RT-PCR analysis (S1C and S1D Fig).