(A) Exponentially growing EndoC-βH2 cells and their two Fucci derivatives EndoC-βH2-OFP-GFZ and EndoC-βH2-PGF2AOF were fixed, permeabilized and stained with the DNA dye Hoechst 33342 to be analyzed for position within cell cycle through their DNA content by flow cytometry. The three cell lines showed a very similar distribution of cells within cell cycle. (B) Expression of beta cell markers in EndoC-βH2 Fucci cells. The expression level of a selected set of genes encoding transcription factors (RFX6, PDX1, NKX6.1) or functional markers (INSULIN, SLC30A8/ZNT8) predominantly or exclusively expressed in beta cells was analyzed by quantitative RT-PCR in EndoC-βH2 cells and in their two Fucci derivatives, EndoC-βH2-OFP-GFZ and EndoC-βH2-PGF2AOF cells. Two PCR experiments, done with the same cDNA samples, were performed (two duplicates per sample), and the mean of the values as well as standard deviations are shown. For each transcript, mRNA levels were normalized to the highest values arbitrarily taken as 100.