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.
Yan
X X
XX
Department of Neurobiology and Behavior, University of California at Irvine, Irvine, CA 92697, USA.
Najbauer
J
J
Woo
C C
CC
Dashtipour
K
K
Ribak
C E
CE
Leon
M
M
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