We recently showed that Tet-dependent 5mC oxidation is operative during lineage specification of neural stem cells (NSCs) 20. Despite being immunochemically undetectable in NSCs, 5fC and 5caC exhibit prominent immunostaining at early stages of NSCs differentiation towards neuronal and glial lineages. Both these marks transiently accumulate concurrently with appearance of the markers of early neuronal and glial differentiation20. To determine the distribution of 5caC in differentiating NSCs we performed co-staining of this mark with a glial marker GFAP on the fixed cultures of NSCs at 3 days of induction of glial differentiation. Unlike in NSCs or mature astrocytes (data not shown), we observed strong 5caC signal in relatively large proportion of the cells expressing GFAP in these cultures (Figure 2)20.