earticle

영어

b-O-linked N-acetylglucosamine (O-GlcNAc) is dynamic post-translational modification in nucleus and cytosol. O-GlcNAc transferase(OGT) and O-GlcNAcase are involved in O-GlcNAc modification. Many proteins such as transcription factors, cytoskeletal proteins and proteins of variable signal transduction pathway are modified with O-GlcNAc at their Ser/Thr residues and their functions are affected by O-GlcNAc. The hexosamine biosynthesis pathway (HBP) consumes about 5% of glucose in total glucose flux, and it’s final product is UDP-GlcNAc, which is source of O-GlcNAc modification. It is reported that O-GlcNAc modification is involved in skeletal muscle metabolism and development process. We studied whether O-GlcNAc modification is involved in differentiation in myoblast C2C12 cell lines. Myoblast C2C12 is differentiated to myotube in differentiation media for 4-5 days. We observed that total O-GlcNAc modification level was dynamically changed during myogenesis. During first 24 hours after induction of myogenesis, total O-GlcNAc modification level decrease and increase again. Moreover, O-GlcNAcase activity increased and total cellular UDP-GlcNAc level decreased at the same time period. Also, we treated NAG-thiazoline derivative, specific O-GlcNAcase inhibitors and observed the block of the decrement of total O-GlcNAc modification and inhibition of myotube formation and expression of myogenic markers. Especially, after treatment NAG-thiazoline derivative, we observed that myogenin expression level decreased. So, we checked the myogenin protein stability using MG132 and mRNA level of myogenin using RT PCR. Even after treatment of MG132, the result of the experiment is same as previous experiment, thus myogenin protein stability is not involved with decrease of myogenin expression after treatment NAG-thiazoline derivative. And using RT PCR, we found that mRNA level of myogenin decrease after treatment NAG-thiazoline derivative. So we conclude that O-GlcNAc modification affect the transcription of myogenin.