Expression of active caspase-3 in mitotic and postmitotic cells of the rat forebrain.
Active caspase-3 immunoreactivity was detected in the rat forebrain proliferative regions at birth and remained high in these areas for about 2 weeks, during which period labeled cells were present centroperipherally across the olfactory bulb. By the end of the third postnatal week, only a small number of immunolabeled cells remained in these forebrain structures. Active caspase-3 immunolabeling was localized mostly to cell nuclei and co-localized partially with TuJ1 and NeuN immunoreactivity, but not with glial fibrially acidic protein, OX-42, gamma-aminobutyric acid, or terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-positive labeling. Active caspase-3 and 5-bromo-2'-deoxyuridine (BrdU) double-labeled nuclei were seen in the proliferative regions after 2 hours and in the periglomerular region of the bulb after 7 days following BrdU injections. Examination of the cells with electron microscopy confirmed that the active caspase-3-containing nuclei in the proliferative regions often had infoldings and appeared to be undergoing division. Some of the cells with active caspase-3-labeled nuclei in the bulb had synapses on their somata or dendrites. Labeled dendritic spines and a few axon terminals were also observed in the olfactory bulb. Taken together, it appears that a wave of active caspase-3-positive cells are dividing in the proliferative zones and then migrating to the bulb as they differentiate into neurons. Therefore, active caspase-3 may play a role in cellular processes such as neuronal differentiation, migration, and plasticity, in addition to its role in cell death.
Department of Neurobiology and Behavior, University of California at Irvine, Irvine, CA 92697, USA.
X X
XX
Yan
J
J
Najbauer
C C
CC
Woo
K
K
Dashtipour
C E
CE
Ribak
M
M
Leon
D000818:Animals; D000906:Antibodies; D000963:Antimetabolites; D001973:Bromodeoxyuridine; D053148:Caspase 3; D020169:Caspases / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D016130:Immunophenotyping; D020287:In Situ Nick-End Labeling; D008297:Male; D008854:Microscopy, Electron; D008938:Mitosis / Q000502:physiology*; D009474:Neurons / Q000201:enzymology* / Q000648:ultrastructure; D009830:Olfactory Bulb / Q000166:cytology* / Q000254:growth & development; D051381:Rats; D017208:Rats, Wistar / Q000378:metabolism*; D013234:Stem Cells / Q000201:enzymology / Q000648:ultrastructure
D000906:Antibodies; D000963:Antimetabolites; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D001973:Bromodeoxyuridine