MyoD alone can activate genes necessary for ________ to become muscle cells.

MyoD alone can activate genes necessary for ________ to become muscle cells.

• A. Neurons
• B. Hepatocytes
• C. Adipocytes
• D. Fibroblasts

Answer: (D)

MyoD is a master regulator that can switch a cell’s fate toward muscle by turning on the muscle gene program. When MyoD is expressed in cells that aren’t already muscle, it binds to muscle gene promoters and activates the cascade of genes needed to become muscle cells, essentially reprogramming the cell’s identity. Fibroblasts are a classic target because they are non-muscle, readily reprogrammable connective-tissue cells. Introducing MyoD into them can trigger the muscle gene network, producing myoblast-like cells and initiating muscle differentiation. That’s why this option fits best: it demonstrates MyoD’s ability to drive myogenesis even in cells not originally destined to become muscle. Neurons, hepatocytes, and adipocytes belong to other lineages, and MyoD alone doesn’t efficiently convert those cell types into muscle in the same straightforward way, since the cellular context and existing programs in those cells resist a muscle fate without additional factors.

MyoD is a master regulator that can switch a cell’s fate toward muscle by turning on the muscle gene program. When MyoD is expressed in cells that aren’t already muscle, it binds to muscle gene promoters and activates the cascade of genes needed to become muscle cells, essentially reprogramming the cell’s identity.

Fibroblasts are a classic target because they are non-muscle, readily reprogrammable connective-tissue cells. Introducing MyoD into them can trigger the muscle gene network, producing myoblast-like cells and initiating muscle differentiation. That’s why this option fits best: it demonstrates MyoD’s ability to drive myogenesis even in cells not originally destined to become muscle.

Neurons, hepatocytes, and adipocytes belong to other lineages, and MyoD alone doesn’t efficiently convert those cell types into muscle in the same straightforward way, since the cellular context and existing programs in those cells resist a muscle fate without additional factors.