Altered expression of pp60c-src induced by peripheral nerve injury.
The normal src protein (pp60c-src) is localized principally in the nerve growth cone of developing neurons and declines to low levels with synaptic maturation. To determine whether pp60c-src is reexpressed in regenerating axons, its expression was studied by immunoblotting and immunocytochemical analyses in adult chicken sciatic nerve following nerve crush injury. pp60c-src expression was found to increase during nerve repair with a temporal and spatial pattern consistent with a localization in regenerating axons. At the crush site, pp60c-src increased to maximal levels 7 days postinjury, increasing fivefold relative to 0 day nerve. In the nerve segment distal to the injury, the maximal increase in pp60c-src was sevenfold and occurred between 11 and 21 days postinjury. Immunoperoxidase staining revealed pp60c-src in regenerating axons and certain nonneuronal cells at the site of nerve repair. pp60c-src was induced in both motor and sensory neurons, as shown by increased pp60c-src immunoreactivity in their cell bodies located in the spinal cord and dorsal root ganglion. Phosphotyrosine-modified proteins that were potential targets of pp60c-src increased following nerve crush, and were localized to outgrowing neurites as well as to nonneuronal cells. These results suggest that pp60c-src is a common component of cellular mechanisms regulating growth cone migration in both regenerating and developing axons.
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599.
M A
MA
Ignelzi
S S
SS
Padilla
D E
DE
Warder
P F
PF
Maness
D000818:Animals; D001369:Axons / Q000378:metabolism; D015415:Biomarkers; D002645:Chickens; D004790:Enzyme Induction; D005260:Female; D009046:Motor Neurons / Q000737:chemistry; D009409:Nerve Crush; D009416:Nerve Regeneration; D009475:Neurons, Afferent / Q000737:chemistry; D059348:Peripheral Nerve Injuries; D010766:Phosphorylation; D019000:Phosphotyrosine; D011499:Protein Processing, Post-Translational; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000096:biosynthesis* / Q000378:metabolism; D009418:S100 Proteins / Q000032:analysis; D012583:Schwann Cells / Q000737:chemistry; D012584:Sciatic Nerve / Q000293:injuries / Q000502:physiology; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D015415:Biomarkers; D009418:S100 Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D016392:Proto-Oncogene Proteins pp60(c-src)