What is the Origin of Myonuclear Domain Expansion?

This term originates from muscle cell biology, where the "myonuclear domain" is a theoretical volume of cytoplasm regulated by a single nucleus. Expansion refers to the necessary increase in nuclear content to support the larger muscle cell.

What is the Mechanism of Myonuclear Domain Expansion?

When mechanical tension and anabolic signals are present, satellite cells fuse with the existing muscle fiber, donating their nuclei. These new myonuclei increase the transcriptional capacity of the fiber, allowing for the synthesis of the necessary structural and contractile proteins to support the increase in cell size. Without this expansion, the muscle fiber's ability to sustain hypertrophy is fundamentally limited.

Myonuclear Domain Expansion ∞ Area

Myonuclear Domain Expansion

Meaning

Myonuclear Domain Expansion is the physiological increase in the volume of cytoplasm that a single myonucleus is responsible for governing within a skeletal muscle fiber. As muscle fibers hypertrophy, new myonuclei must be incorporated via satellite cell fusion to maintain a constant myonuclear domain size, ensuring adequate protein synthesis for the enlarged cellular volume. This expansion is a prerequisite for sustained muscle growth and strength gains.