Figure 4.

Hierarchy of transcription factors regulating myogenic lineage. This figure represents the major transcription factors involved in muscle development and shows their temporal sequence of activation across various stages of myogenesis. Satellite stem cells expressing PAX7 derive from the PAX3/PAX7 expressing progenitors, whereas satellite myogenic cells additionally exhibit an activation of MYF5. Following activation and entrance into the cell cycle, stem cells express MYF5 and MYOD1. Activation of MYOG and MEF2C, with downregulation of MYF5 and later MYOD1 mark the start of terminal differentiation. Activation of MRF4 happens several days after the induction of differentiation, following a reduction in MYOG