Expression levels of B-50/GAP-43 in PC12 cells are decisive for the complexity of their neurites and growth cones.
To study the role of the protein B-50/GAP-43 in NGF-induced neurite outgrowth, a number of stable PC12 subclones with either very low or considerably enhanced expression levels of the protein were selected. Cell bodies of subclones with suppressed B-50 expression (-B2, -B5, or -B12) possessed a relative small spherical shape and, on NGF-treatment for 7 d, developed processes that were virtually devoid of branches and that mostly bore short or blunt-ended growth cones. Cells of subclones with overexpression of B-50 (+B3, +B4, or +B11), on NGF treatment, acquired a flattened, spiky appearance with highly branched neurites possessing extended and complex growth cones. Confocal microscopy with immunofluorescence for B-50 and F-actin revealed that in neurites and growth cones of the B-50-deficient subclone -B2, no detectable B-50 and reduced amounts of filamentous F-actin were present, whereas in overexpressing +B3 cells, cell membranes, neurites, and complex growth cones were intensively stained for B-50 and exhibited numerous spikes, in which B-50 was strikingly colocalized with F-actin. These data suggest that, under normal conditions of neuritogenesis, the expression level of B-50 in PC12 cells is decisive for the complexity of neurites and growth cones.
Jap Tjoen San
E R
ER
Department for Physiological Chemistry, Medical Faculty, Rudolf Magnus Institute for Neurosciences, Utrecht University, The Netherlands.
van Rozen
A J
AJ
Nielander
H B
HB
Oestreicher
A B
AB
Gispen
W H
WH
Schotman
P
P
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D019922:GAP-43 Protein; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000235:genetics*; D008857:Microscopy, Interference; D009414:Nerve Growth Factors / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics*; D016501:Neurites / Q000502:physiology*; D016900:Neurofilament Proteins / Q000235:genetics*; D016716:PC12 Cells / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats
D019922:GAP-43 Protein; D008562:Membrane Glycoproteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D012333:RNA, Messenger