Down-Regulation of Transcription Factors AP-1, Sp-1, and NF-κB Precedes Myocyte Differentiation

摘要: Terminal differentiation of myocytes involves withdrawal from the cell cycle, induction myogenin expression, and finally formation myotubes. To study factors that regulate initial phase muscle differentiation, we analyzed binding activities transcription AP-1, Sp-1, NF-kappa B in L6, C2C12, rhabdomyosarcoma BA-Han-1C cells. Temporal changes factor were compared to activation promoter-driven CAT reporter gene expression level myogenin, a master myogenic differentiation. We observed prominent decrease nuclear already 12 24 h after transfer cells medium. The response was very similar L6 C2C12 down-regulation clearly preceded promoter retinoblastoma as well initiation myocyte fusion. Cholera toxin okadaic acid, established inhibitors strongly up-regulated Myogenin fusion also inhibited. Levels c-Fos c-Jun proteins, components AP-1 complex, showed These results show proliferation-promoting is prerequisite