Immediate early gene expression in axotomized and regenerating retinal ganglion cells of the adult rat.
To determine if axotomy-induced immediate early gene (IEG) expression accompanies regenerative efforts in central nervous system (CNS) neurons, immunohistochemistry using antibodies to c-Jun, JunD, JunB, c-Fos, FosB and Krox-24 proteins was used to examine gene expression in identified adult rat retinal ganglion cells (RGCs) under two conditions: (1) after axotomy alone, and (2) 1 month after replacement of the optic nerve with an autologous peripheral nerve graft to allow axonal regrowth. Strong RGC c-Jun expression was induced 1 day, but not 3 h, after axotomy in most RGCs and was maintained in surviving cells throughout the 3-week study period. Axotomy also induced a limited number of RGCs to express Krox-24, but only transiently. c-Fos expression was also seen in a limited number of control RGCs, however, it was not induced by axotomy. Nucleolar FosB immunoreactivity in axotomized RGCs persisted 1 day after axotomy, but was subsequently lost. One month after axotomy and peripheral nerve graft placement, identified RGCs with regrown axons showed only nuclear c-Jun and nucleolar FosB expression. These findings support a role for IEG expression in the regeneration process of CNS neurons.
Department of Physiology (CB 7545), University of North Carolina at Chapel Hill 27599-7545.
G A
GA
Robinson
D000818:Animals; D001369:Axons / Q000502:physiology; D004268:DNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis; D051766:Early Growth Response Protein 1; D005260:Female; D015870:Gene Expression; D017781:Genes, Immediate-Early; D017874:Immediate-Early Proteins; D007150:Immunohistochemistry; D009416:Nerve Regeneration; D009900:Optic Nerve / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology / Q000637:transplantation; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000096:biosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D012165:Retinal Ganglion Cells / Q000502:physiology*; D014157:Transcription Factors / Q000032:analysis / Q000096:biosynthesis
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors