Figure 1. Extrinsic and intrinsic determinants of cell fate in muscle stem cells. The satellite cell niche is highly asymmetric. Satellite cells can be in contact with the muscle fiber on their apical pole or with the extracellular matrix of the basal lamina at the basal pole. Cell-cell contacts and cell-matrix receptors induce polarity signals, allowing for positioning of the mitotic spindle apparatus and the induction of fate determinants after division. Myf5- satellite stem cells (ochre) express high levels of Pax7. However, transcription of the Myf5 locus is repressed. Upon asymmetric division, Carm1 methylates Pax7 and allows for the recruitment of the MLL/ASH2L HMT complex, which leads to the remodeling of chromatin at the Myf5 locus followed by transcription of Myf5 mRNA and myogenic commitment of the apical daughter cell (green).