Charcot-Marie-Tooth Disease/pathology; Microfilament Proteins/metabolism; Myelin Sheath/metabolism; Myelin Sheath/pathology; Schwann Cells/metabolism; Age Factors; Animals; Cells, Cultured; Charcot-Marie-Tooth Disease/genetics; Disease Models, Animal; Electric Stimulation; Endocytosis/drug effects; Endocytosis/genetics; Evoked Potentials, Motor/genetics; Gene Expression Regulation/drug effects; Gene Expression Regulation/genetics; Homeodomain Proteins/genetics; Mice; Mice, Transgenic; Microfilament Proteins/genetics; Microscopy, Electron, Transmission; Mutation/genetics; Myelin Proteolipid Protein/genetics; Myelin Sheath/genetics; RNA, Small Interfering/pharmacology; Schwann Cells/drug effects; Schwann Cells/ultrastructure; Sciatic Nerve/cytology; Sciatic Nerve/pathology; Sciatic Nerve/physiopathology; Transcription Factors/deficiency; Transcription Factors/genetics; Transferrin/metabolism; cdc42 GTP-Binding Protein/metabolism