Muscle regeneration controlled by a designated DNA dioxygenase (ATAC-Seq)

DNA methylation plays critical roles in regulating muscle cell fate determination and myogenesis. Tet dioxygenases are responsible for active DNA demethylation. The functions of Tet proteins in muscle regeneration have not been well characterized. Here we find that Tet2 is required for complete regeneration after muscle injury. Loss of Tet2 in myoblasts leads to reduced fusion index and thinner myofibers. Tet2 activates transcription of key differentiation modulator Myogenin (MyoG) further promoting myoblast differentiation and fusion. Re-expressing of MyoG in Tet2 KO myoblasts rescues the differentiation and fusion defects. Further mechanistic analysis reveals that Tet2 facilitates the recruitment of H3K4me1 and H3K27ac, increases the chromatin accessibility, and MyoD binding on MyoG enhancer. These functions are specifically executed by Tet2, but not Tet1 and Tet3. We identified the Tet2 specific function during myogenesis and shed new lights on DNA methylation and pioneer transcription factor transcription activation. Examine RNA expression, DNA methylation and chromatin accessibility differences between Tet2 KO and WT mouse primary myoblasts.