Transcriptional profiling of chemical Dot1L inhibition during reprogramming to induced pluripotent stem cells

Three independent transcriptional profiling experiments were performed to ascertain how Dot1L affects cell fate change. 1) In a timecoure ("Tc"), reprogramming mouse embryonic fibroblasts were treated with DMSO control or Dot1L inhibitor (Dot1Li -SGC0946) for 2 or 4 days. Surprisingly, despite the enrichment of H3K79me2 on thousands of actively transcribed genes, Dot1L inhibition (Dot1Li) results in few changes in steady state mRNA levels during reprogramming, the majority of which are spuriously upregulated. 2) To determine if Dot1Li increased reprogramming beyond the mesenchymal to epithelial transition (MET) that occurs early in reprogramming when starting from MEFs, reprogramming cells were sorted ("Sort") for surface CDH1 expression, and then treated with Dot1Li or control. Dot1Li increased reprogramming efficiency of both CDH1- and CDH1+ populations to a similar extent and few genes were DE. 3) To assess if Dot1Li increased pluripotency acquisition beyond CDH1 upregulation, CDH1 or empty vector was expressed ("Exp") in reprogramming cells. CDH1 expression did not initiate MET, or enhance reprogramming. Overall design: mRNA profiles of MEFs, ESCs, and reprogramming cells with Dot1L chemical inhibition