Regulatory Dynamics of Tet1 and Oct4 Resolve Stages of Global DNA Demethylation and Transcriptomic Changes in Reprogramming

Regulatory Dynamics of Tet1 and Oct4 Resolve Stages of Global DNA Demethylation and Transcriptomic Changes in Reprogramming

Blog Article

Summary: Reprogramming somatic cells into induced pluripotent stem cells (iPSCs) involves the reactivation of endogenous pluripotency genes and global DNA demethylation, but temporal resolution of these events using existing markers is limited.Here, we generate murine transgenic lines harboring reporters for the 5-methylcytosine dioxygenase Tet1 and for Oct4.By monitoring dual reporter fluorescence during pluripotency entry, we identify a sequential order of Tet1 and Oct4 activation by proximal and distal regulatory elements.Full Tet1 here activation marks an intermediate stage that accompanies predominantly repression of somatic genes, preceding full Oct4 activation, and distinguishes two waves of global DNA demethylation that target distinct genomic features but are uncoupled from transcriptional changes.

Tet1 knockout shows that TET1 contributes to both waves of demethylation and activates germline regulatory genes in reprogramming intermediates but is dispensable for Oct4 reactivation.Our dual reporter system for time-resolving pluripotency entry thus refines the molecular roadmap of iPSC maturation.: By monitoring activation kinetics of Tet1 and Oct4 cell state-specific regulatory elements, Bartoccetti et al.identify phases of gene expression changes uncoupled from two waves of global DNA radio birdman tshirt demethylation late in reprogramming.

Stage-specific functions of TET1 regulate germline regulators during reprogramming and somatic lineage genes during maintenance of pluripotency.Keywords: epigenetics, induced pluripotent stem cells, reprogramming roadmap, germline, chromatin remodelling, genomics, transgenic reporters, gene activation kinetics.