LAUSR

O‐GlcNAcylation is a posttranslational modification considered to be a nutrient sensor that reports nutrient scarcity or surplus. Although O‐GlcNAcylation exists in a wide range of cells and/or tissues, its functional role in muscle satellite cells (SCs) remains largely unknown. Using a genetic approach, we ablated O‐GlcNAc transferase (OGT), and thus O‐GlcNAcylation, in SCs. We first evaluated SC function in vivo using a muscle injury model and found that OGT deficient SCs had compromised capacity to repair muscle after an acute injury compared with the wild‐type SCs. By tracing SC cycling rates in vivo using the doxycycline‐inducible H2B‐GFP mouse model, we found that SCs lacking OGT cycled at lower rates and reduced in abundance with time. Additionally, the self‐renewal ability of OGT‐deficient SCs after injury was decreased compared to that of the wild‐type SCs. Moreover, in vivo, in vitro, and ex vivo proliferation assays revealed that SCs lacking OGT were incapable of expanding compared with their wild‐type counterparts, a phenotype that may be explained, at least in part, by an HCF1‐mediated arrest in the cell cycle. Taken together, our findings suggest that O‐GlcNAcylation plays a critical role in the maintenance of SC health and function in normal and injured skeletal muscle.