The transcription factor MyoD can coax na?e fibroblasts or otherwise committed cells to adopt the skeletal muscle phenotype by activating the muscle gene expression program. Activation of muscle gene expression occurs in quantal steps with not all the target genes of MyoD being activated at the same time. Some genes are induced in the initial phases, others at later stages despite the fact that MyoD is present throughout the differentiation process. MyoD is post-translationally modified by phosphorylation, ubiquitination, and acetylation. Here, we have employed a model system in which MyoD and its non-acetylatable version were inducibly expressed in mouse embryonic fibroblasts derived from mice to investigate how MyoD acetylation may contribute to differential gene activation.