Effect of a myofiber-specific HIRA conditional knockout on gene expression in mouse skeletal muscle at 6 months of age

We performed gene expression profiling by microarray using RNA extracted from the tibialis anterior of control and Hira myofiber-specific conditional knockout mice at 6 months of age. Hira is a histone chaperone responsible for replication-independent incorporation of histone variant H3.3 at actively transcribed loci. Conditional knockout of Hira in myofibers improved strength and endurance, caused hypertrophy and regeneration, and increased the percentage of type I fibers. These results illustrate the physiological consequences of disrupting Hira-mediated chromatin assembly in myofibers. 4 animals per group (control and Hira conditional knockout) hybridized in triplicate. RNA was extracted from the tibialis anterior muscle.