Stem cells in skeletal muscle growth and regeneration in amniotes and teleosts: Emerging themes

Skeletal muscle is a contractile, postmitotic tissue that retains the capacity to grow and regenerate throughout life in amniotes and teleost. Both muscle growth and regeneration are regulated by obligate tissue resident muscle stem cells. Given that considerable knowledge exists on the myogenic process, recent studies have focused on examining the molecular markers of muscle stem cells, and on the intrinsic and extrinsic signals regulating their function. From this, two themes emerge: firstly, muscle stem cells display remarkable heterogeneity not only with regards to their gene expression profile, but also with respect to their behavior and function; and secondly, the stem cell niche is a critical regulator of muscle stem cell function during growth and regeneration. Here, we will address the current understanding of these emerging themes with emphasis on the distinct processes used by amniotes and teleost, and discuss the challenges and opportunities in the muscle growth and regeneration fields.