During Ngn2-neuronal induction, a non-neuronal population appears within the first week of induction and rapidly expands. Expansion of these cells decreases the purity of neurons, a particular concern when performing biochemical, transcriptomic, epigenomic or other population-wide analyses. Ara-C is a DNA analog that prevents cellular replication while not interfering with gene expression. It has been widely used to eliminate glia, when culturing primary neurons isolated from rodent brains [37]. We tested the ability of Ara-C to reduce contamination by proliferative cells during extended Ngn2-induction protocols from NPCs (Fig. 4F–H).
