The Cycle the Protein Appears to GovernMuscle stem cells, also called satellite cells, remain inactive until tissue is injured. They then activate, multiply, rebuild the damaged area, and produce replacement stem cells that return to a dormant state. Rather than acting only at chromosome ends, TRF2 binds regulatory regions across the genome that control genes essential for muscle stem cell identity. The Reason Muscle Stem Cell Research Draws AttentionThe interest in this line of work comes from three overlapping problems. It binds regulatory regions across the genome that control muscle stem cell identity genes, many of them containing secondary DNA structures called G-quadruplexes.