c-Jun regulation in rat neonatal motoneurons postaxotomy.
Motoneurons respond to peripheral nerve transection by either regenerative or degenerative events depending on their state of maturation. Since the expression of c-Jun has been involved in the early signalling of the regenerative process that follows nerve transection in adults, we have investigated c-Jun on rat neonatal axotomized motoneurons during the period in which neuronal death is induced. Changes in levels of c-Jun protein and its mRNA were determined by means of quantitative immunocytochemistry and in situ hybridization. Three hours after nerve transection performed on postnatal day (P)3, c-Jun protein and mRNA is induced in axotomized spinal cord motoneurons, and high levels were reached between 1 and 10 days after. This response is associated with a detectable c-Jun activation by phosphorylation on serine 63. No changes were found in the levels of activating transcription factor -2. Most of dying motoneurons were not labelled by either a specific c-Jun antibody or a c-jun mRNA probe. However, dying motoneurons were specifically stained by a polyclonal anti c-Jun antibody, indicating that some c-Jun antibodies react with unknown epitopes, probably distinct from c-Jun p39, that are specifically associated with apoptosis.
Unitat de Neurobiologia Cellular, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Spain.
A
A
Casanovas
J
J
Ribera
G
G
Hager
G W
GW
Kreutzberg
J E
JE
Esquerda
D051698:Activating Transcription Factor 2; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies; D017209:Apoptosis / Q000502:physiology*; D019771:Axotomy; D017362:Cyclic AMP Response Element-Binding Protein / Q000032:analysis / Q000276:immunology; D015870:Gene Expression / Q000502:physiology; D017781:Genes, Immediate-Early / Q000502:physiology; D017403:In Situ Hybridization; D009046:Motor Neurons / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D014157:Transcription Factors / Q000032:analysis / Q000276:immunology
D051698:Activating Transcription Factor 2; D000906:Antibodies; C497107:Atf2 protein, rat; D017362:Cyclic AMP Response Element-Binding Protein; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D014157:Transcription Factors