Type II myonuclei

In skeletal muscle, myonuclei within fast-twitch (Type II) muscle fibers. These fibers are glycolytic, generate more force but fatigue quickly. Type II myonuclei (subtypes IIa, IIx/d) govern the expression of genes for glycolytic enzymes, fast myosin heavy chains, and other components defining the fast, anaerobic metabolic phenotype of the fiber.