A key event in the development of the mammalian cerebral cortex is the generation of neuronal populations during embryonic life. Previous studies have revealed many details of cortical neuron development including cell birthdates, migration patterns and lineage relationships. Programmed cell death is a potentially important mechanism that could alter the numbers and types of developing cortical cells during these early embryonic phases. While programmed cell death has been documented in other parts of the embryonic central nervous system, its operation has not been previously reported in the embryonic cortex because of the lack of cell death markers and the difficulty in following the entire population of cortical cells. Here, we have investigated the spatial and temporal distribution of dying cells in the embryonic cortex using an in situ endlabelling technique called ‘ISEL+’ that identifies fragmented nuclear DNA in dying cells with increased sensitivity. The period encompassing murine cerebral cortical neurogenesis was examined, from embryonic days 10 through 18. Dying cells were rare at embryonic day 10, but by embryonic day 14, 70% of cortical cells were found to be dying. This number declined to 50% by embryonic day 18, and few dying cells were observed in the adult cerebral cortex. Surprisingly, while dying cells were observed throughout the cerebral cortical wall, the majority were found within zones of cell proliferation rather than in regions of postmitotic neurons. These observations suggest that multiple mechanisms may regulate programmed cell death in the developing cortex. Moreover, embryonic cell death could be an important factor enabling the selection of appropriate cortical cells before they complete their differentiation in postnatal life.

Reference

Abrams
J. M.
,
White
K.
,
Fessler
L. I.
,
Steller
H.
(
1993
)
Programmed cell death during Drosophila embryogenesis.
Development
117
,
29
43
Austin
C. P.
,
Cepko
C. L.
(
1990
)
Cellular migration patterns in the developing mouse cerebral cortex.
Development
110
,
713
732
Barres
B. A.
,
Hart
I. K.
,
Coles
H. S.
,
Burne
J. F.
,
Voyvodic
J. T.
,
Richardson
W. D.
,
Raff
M. C.
(
1992
)
Cell death and control of cell survival in the oligodendrocyte lineage.
Cell
70
,
31
46
Bayer
S.
,
Altman
J.
(
1990
)
Development of layer I and the subplate in the rat neocortex.
Exp. Neurol
107
,
48
62
Berry
M.
,
Rogers
A. W.
(
1965
)
The migration of neuroblasts in the developing cerebral cortex.
J. Anat
99
,
691
709
Boulder Committee
(
1970
)
Embryonic vertebrate central nervous system: revised terminology.
Anat. Rec
166
,
257
261
Caelles
C.
,
Helmberg
A.
,
Karin
M.
(
1994
)
p53-dependent apoptosis in the absence of transcriptional activation of p53-target genes.
Nature
370
,
220
223
Caviness
V. S. J.
(
1982
)
Neocortical histogenesis in normal and reeler mice: a developmental study based upon [3H]thymidine autoradiography.
Dev. Brain Res
4
,
293
302
Caviness
V. S. J.
,
Takahashi
T.
,
Nowakowski
R. S.
(
1995
)
Numbers, time and neocortical neuronogenesis: a general developmental and evolutionary model.
Trends Neurosci
18
,
379
383
Chun
J. J. M.
,
Schatz
D. G.
,
Oettinger
M. A.
,
Jaenisch
R.
,
Baltimore
D.
(
1991
)
The recombination activating gene-1 (RAG-1) transcript is present in the murine central nervous system.
Cell
64
,
189
200
Chun
J. J. M.
,
Shatz
C. J.
(
1989
)
Interstitial cells of the adult neocortical white matter are the remnant of the early generated subplate neuron population.
J. Comp. Neurol
282
,
555
569
Clarke
P. G.
,
Rogers
L. A.
,
Cowan
W. M.
(
1976
)
The time of origin and the pattern of survival of neurons in the isthmo-optic nucleus of the chick.
J. Comp. Neurol
167
,
125
142
Cowan
W. M.
,
Fawcett
J. W.
,
O'Leary
D. D. M.
,
Stanfield
B. B.
(
1984
)
Regressive events in neurogenesis.
Science
225
,
1258
1265
Crespo
D.
,
O'Leary
D. D. M.
,
Cowan
W. M.
(
1985
)
Changes in the numbers of optic nerve fibers during late prenatal and postnatal development in the albino rat.
Dev. Brain Res
19
,
129
134
Cunningham
T. J.
,
Mohler
I. M.
,
Giordano
D. L.
(
1982
)
Naturally occurring neuron death in the ganglion cell layer of the neonatal rat: morphology and evidence for regional correspondence with neuron death in superior colliculus.
Dev. Brain Res
2
,
203
215
Das
G. D.
(
1979
)
Gliogenesis and ependymogenesis during embryonic development of the rat. An autoradiographic study.
J. Neur. Sci
43
,
193
204
Davis
A. A.
,
Temple
S.
(
1994
)
A self-renewing multipotential stem cell in embryonic rat cerebral cortex.
Nature
372
,
263
266
Derer
P.
,
Derer
M.
(
1990
)
Cajal-Retzius cell ontogenesis and death in mouse brain visualized with horseradish peroxidase and electron mircroscopy.
Neuroscience
36
,
839
856
Egerton
M.
,
Scollay
R.
,
Shortman
K.
(
1990
)
Kinetics of mature T-cell development in the thymus.
Proc. Natl Acad. Sci. USA
87
,
2579
2582
Ferrer
I.
,
Soriano
E.
,
Del Rio
J. A.
,
Alcantara
S.
,
Auladell
C.
(
1992
)
Cell Death and Removal in the Cerebral Cortex During Development.
Prog. Neurobiol
39
,
1
43
Finlay
B. L.
,
Slattery
M.
(
1983
)
Local differences in the amount of early cell death in neocortex predict adult local specializations.
Science
219
,
1349
1351
Flanagan
A. E.
(
1969
)
Differentiation and degeneration in the motor horn of the foetal mouse.
J. Morph
129
,
281
305
Gavrieli
Y.
,
Sherman
Y.
,
Ben-Sasson
S. A.
(
1992
)
Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation.
J. Cell Biol
119
,
493
501
Hamburger
V.
(
1975
)
Cell death in the development of the lateral motor column of the chick embryo.
J. Comp. Neurol
160
,
535
546
Hamburger
V.
,
Levi-Montalcini
R.
(
1949
)
Proliferation, differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions.
J. Exp. Zool
111
,
457
502
Heumann
D.
,
Leuba
G.
(
1983
)
Neuronal death in the development and aging of the cerebral cortex of the mouse.
Neuropath. Appl. Neurobiol
9
,
297
311
Hicks
S. P.
,
D'Amato
C. J.
(
1968
)
Cell migrations to the isocortex in the rat.
Anat. Rec
160
,
619
634
Homma
S.
,
Yaginuma
H.
,
Oppenheim
R. W.
(
1994
)
Programmed cell death during the earliest stages of spinal cord development in the chick embryo: a possible means of early phenotypic selection.
J. Comp. Neurol
343
,
377
395
Horsburgh
G. M.
,
Sefton
A. J.
(
1987
)
Cellular degeneration and synaptogenesis in the developing retina of the rat.
J. Comp. Neurol
263
,
553
566
Kostovic
I.
,
Rakic
P.
(
1990
)
Developmental history of the transient subplate zone in the visual and somatosensory cortex of the macaque monkey and human brain.
J. Comp. Neurol
297
,
441
470
Lam
K.
,
Sefton
A. J.
,
Bennett
M. R.
(
1982
)
Loss of axons from the optic nerve of the rat during early postnatal development.
Brain Res
255
,
487
491
Landmesser
L.
,
Pilar
G.
(
1974
)
Synaptic transmission and cell death during normal ganglionic development.
J. Physiol
241
,
737
749
Linden
R.
,
Pinto
L. H.
(
1985
)
Developmental genetics of the retina: evidence that the pearl mutation in the mouse affects the time course of natural cell death in the ganglion cell layer.
Exp. Brain Res
60
,
79
86
Luskin
M. B.
,
Pearlman
A. L.
,
Sanes
J. R.
(
1988
)
Cell lineage in the cerebral cortex of the mouse studied in vivo and in vitro with a recombinant retrovirus.
Neuron
1
,
635
47
Matsuyama
M.
,
Wiadrowski
M. N.
,
Metcalf
D.
(
1966
)
Autoradiographic analysis of lymphopoiesis and lymphocyte migration in mice bearing multiple thymus grafts.
J. Exp. Med
123
,
559
576
Miller
N.
,
Oberdorfer
M.
(
1981
)
Neuronal and neuroglial responses following retinal lesions in the neonatal rats.
J. Comp. Neurol
202
,
493
504
Mission
J. P.
,
Takahashi
T.
,
Caviness
V. S. J.
(
1991
)
Ontogeny of radial and other astroglial cells in murine cerebral cortex.
Glia
4
,
138
148
Oppenheim
R. W.
(
1985
)
Naturally occurring cell death during neural development.
Trends Neurosci
8
,
487
493
Oppenheim
R. W.
(
1991
)
Cell death during development of the nervous system.
Ann. Rev. Neurosci
14
,
453
501
Parnavelas
J. G.
,
Barfield
J. A.
,
Franke
E.
,
Luskin
M. B.
(
1991
)
Separate progenitor cells give rise to pyramidal and nonpyramidal neurons in the rat telencephalon.
Cereb. Cort
1
,
463
468
Perry
V. H.
,
Henderson
Z.
,
Linden
R.
(
1983
)
Postnatal changes in retinal ganglion cell and optic axon populations in the pigmented rat.
J. Comp. Neurol
219
,
356
368
Potts
R. A.
,
Dreher
B.
,
Bennett
M. R.
(
1982
)
The loss of ganglion cells in the developing retina of the rat.
Brain Res
255
,
481
486
Price
D. J.
,
Blakemore
C.
(
1985
)
Regressive events in the postnatal development of association projections in the visual cortex.
Nature
316
,
721
724
Price
J.
,
Thurlow
L.
(
1988
)
Cell lineage in the rat cerebral cortex: a study using retroviral-mediated gene transfer.
Development
104
,
473
482
Raff
M. C.
,
Barres
B. A.
,
Burne
J. F.
,
Coles
H. S.
,
Ishizaki
Y.
,
Jacobson
M. D.
(
1993
)
Programmed cell death and the control of cell survival: lessons from the nervous system.
Science
262
,
695
700
Rakic
P.
(
1976
)
Prenatal genesis of connections subserving ocular dominance in the rhesus monkey.
Nature
261
,
467
471
Rakic
P.
(
1977
)
Prenatal development of the visual system in rhesus monkey.
Phil. Trans. R. Soc. Lond
278
,
245
260
Saunders
J. W.
(
1966
)
Death in embryonic systems.
Science
154
,
604
612
Shatz
C. J.
,
Rakic
P.
(
1981
)
The genesis of efferent connections from the visual cortex of the fetal rhesus monkey.
J. Comp. Neurol
196
,
287
307
Shortman
K.
,
Egerton
M.
,
Spangrude
G. J.
,
Scollay
R.
(
1990
)
The generation and fate of thymocytes.
Sem. Immunol
2
,
3
12
Surh
C. D.
,
Sprent
J.
(
1994
)
T-cell apoptosis detected in situduring positive and negative selection in the thymus.
Nature
372
,
100
103
Takahashi
T.
,
Nowakowski
R. S.
,
Caviness
V. S.
(
1993
)
Cell cycle parameters and patterns of nuclear movement in the neocortical proliferative zone of the fetal mouse.
J. Neurosci
13
,
820
833
Takahashi
T.
,
Nowakowski
R. S.
,
Caviness
V. S.
(
1995
)
The cell cycle of the pseudostratified ventricular epithelium of the embryonic murine cerebral wall.
J. Neurosci
15
,
6046
6057
Walsh
C.
,
Cepko
C. L.
(
1988
)
Clonally related cortical cells show several migration patterns.
Science
241
,
1342
1345
White
K.
,
Grether
M. E.
,
Abrams
J. M.
,
Young
L.
,
Farrell
K.
,
Steller
H.
(
1994
)
Genetic control of programmed cell death in Drosophila.
Science
264
,
677
683
Wijsman
J. H.
,
Jonker
R. R.
,
Keijzer
R.
,
van de Velde
C. J.
,
Cornelisse
C. J.
,
van Dierendonck
J. H.
(
1993
)
A new method to detect apoptosis in paraffin sections: in situ end-labeling of fragmented DNA.
J. Histochem. Cytochem
41
,
7
12
Williams
G. T.
,
Smith
C. A.
(
1993
)
Molecular regulation of apoptosis: genetic controls on cell death.
Cell
74
,
777
779
Williams
R. W.
,
Herrup
K.
(
1988
)
The control of neuron number.
Ann. Rev. Neurosci
11
,
423
453
Wood
J. G.
,
Martin
S.
,
Price
D. J.
(
1992
)
Evidence that the earliest generated cells of the murine cerebral cortex form a transient population in the subplate and marginal zone.
Brain Res
66
,
137
140
Wood
K. A.
,
Dipasquale
B.
,
Youle
R. J.
(
1993
)
In situ labeling of granule cells for apoptosis-associated DNA fragmentation reveals different mechanisms of cell loss in developing cerebellum.
Neuron
11
,
621
632
Woodhams
P. L.
,
Basco
E.
,
Hajos
F.
,
Csillag
A.
,
Balazs
R.
(
1981
)
Radial glia in the developing mouse cerebral cortex and hippocampus.
Anat. Embryol
163
,
331
343
Wyllie
A. H.
(
1980
)
Glucocorticoid-induced thymocyte apoptosis is associated with endogenous endonuclease activation.
Nature
284
,
555
556
Wyllie
A. H.
,
Morris
R. G.
,
Smith
A. L.
,
Dunlop
D.
(
1984
)
Chromatin cleavage in apoptosis: association with condensed chromatin morphology and dependence on macromolecular synthesis.
J. Pathol
142
,
67
77
Young
R. W.
(
1984
)
Cell death during differentiation of the retina in the mouse.
J. Comp. Neurol
229
,
362
373
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