Figure 5. Myf5 −111kb (ECR111) Is a Common Evolutionarily Conserved Target of Pax3/7.

(A) Schematic of the regulatory regions for Myf5 depicting the multitude of enhancer elements that direct Myf5 expression at different times and at different anatomical locations. (B) Pax3 binding sites are found at −129kb, −111kb, and −57.5kb, as determined by ChIP-Seq analysis primary myoblasts stably expressing Pax3. The regulatory element at −57.5kb directs Myf5 expression in somites, trunk, and limb muscles (Bajard et al., 2006). Pax7 binding sites are also present on Myf5/6 regulatory region, and are found within the satellite cell region as well as regions directing expression in limbs and muscle spindles. Pax7 commonly binds all Pax3 sites, however the peak at −111kb is the most enriched. Also see Figure S5 for binding of Pax3 and Pax7 of a representative set of known targets. (C) Chromatogram of Myf5 −57kb probe incubated with Pax3 or Pax7 (red) or BSA (blue) and digested with DNaseI. The 29-bp footprint (black bar) is identical between Pax3 and Pax7, centered on a paired domain motif. (D) Chromatogram of Myf5 −111kb probe. Identical protected regions (black bar) were observed in the presence of Pax3 or Pax7. The footprint spans a region containing a putative paired domain and a separate homeo domain motif (Wilson et al., 1993). The distance between each motif and the length of the footprint implies that multiple Pax7 molecules may simultaneously bind