Terminal differentiation program of skeletal myogenesis is negatively regulated by O-GlcNAc glycosylation.

abstract Article history:Received 23 April 2011Received in revised form 14 September 2011Accepted 20 October 2011Available online 26 October 2011Keywords:C2C12DifferentiationGlycosylationMyoblastMyogenesisO-GlcNAc Background: O-Linked β-N-acetylglucosaminylation (O-GlcNAcylation) on the Ser/Thr residue of nucleocyto-plasmic proteins is a dynamic post-translational modification found in multicellular organisms. More than500 proteins involved in a wide range of cellular functions, including cell cycle, transcription, epigenesis,and glucose sensing, are modified with O-GlcNAc. Although it has been suggested that O-GlcNAcylation is in-volved in the differentiation of cells in a lineage-specific manner, its role in skeletal myogenesis is unknown.Methods and results: A myogenesis-dependent drastic decrease in the levels of O-GlcNAcylation was found inmouse C2C12 myoblasts. The global decrease in O-GlcNAcylation was observed at the earlier stage of myo-genesis, prior to myoblast fusion. Genetic or pharmacological inactivation of O-GlcNAcase blocked both themyogenesis-dependent global decrease in O-GlcNAcylation and myoblast fusion. Although inactivation ofO-GlcNAcase affected neither cell-cycle exit nor cell survival in response to myogenic stimulus, it perturbedthe expression of myogenic regulatory factors. While the expression of myod and myf5 in response tomyogenic induction was not affected, that of myogenin and mrf4 was severely inhibited by the inactivationof O-GlcNAcase.Conclusion: These results indicate that the terminal differentiation program of skeletal myogenesis is nega-tively regulated by O-GlcNAcylation.General significance: O-GlcNAcylation is involved in differentiation in a cell lineage-dependent manner, and adecrease in O-GlcNAcylation may have a common role in the differentiation of cells of muscle lineage.© 2011 Elsevier B.V. All rights reserved.