Influence of the embryonic preplate on the organization of the cerebral cortex: a targeted ablation model.
Transgenic mice were generated to permit the targeted ablation of cortical preplate cells at the time they are born. In these mice, the 1.3 kb golli promoter of the myelin basic protein gene was used to drive the herpes simplex virus thymidine kinase (TK) transgene in cortical preplate cells. Heterozygous transgenic pairs were bred, and pregnant dams were treated with ganciclovir at embryonic days 11-12 to ablate preplate cells at the time the preplate was forming. This paradigm exposed control (TK-) and experimental (TK+) littermates to exactly the same conditions. Embryological ablation of preplate cells led to an early disruption of the radial glial framework and subplate structure in the developing cortex and dramatically altered the cellular lamination and connectivity of the cortical plate. The disturbed radial glial network contributed to an impaired radial migration of neurons into the cortical plate from the ventricular zone. The cortical plate became dyslaminated, and there was a substantial reduction in short- and long-range cortical projections within the cortex and to subcortical regions. Cell death within the cortical plate and the proliferative zones was substantially increased in the ablated animals. After birth, a cortical lesion developed, which became exacerbated with the secondary onset of hydrocephaly in the second postnatal week. The results underscore the critical importance of the preplate in cortex formation, mediated through its guidance of the formation of radial glial scaffolding, subsequent neuronal migration into the incipient cortical plate, and the final arrangement of its vertical organization and cellular connectivity.
Xie
Y
Y
Developmental and Molecular Neuroscience Group, Neuropsychiatric Institute, University of California at Los Angeles, School of Medicine, Los Angeles, California 90024-1759, USA.
Skinner
E
E
Landry
C
C
Handley
V
V
Schonmann
V
V
Jacobs
E
E
Fisher
R
R
Campagnoni
A
A
D000818:Animals; D001973:Bromodeoxyuridine; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002465:Cell Movement / Q000187:drug effects; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D004628:Embryonic Structures / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D015774:Ganciclovir / Q000494:pharmacology; D006849:Hydrocephalus / Q000139:chemically induced / Q000235:genetics / Q000473:pathology; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D004676:Myelin Basic Protein / Q000235:genetics; D009421:Nervous System Malformations / Q000139:chemically induced / Q000235:genetics / Q000473:pathology; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D011401:Promoter Regions, Genetic / Q000235:genetics; D018139:Simplexvirus / Q000235:genetics; D013937:Thymidine Kinase / Q000096:biosynthesis / Q000235:genetics
D004676:Myelin Basic Protein; D013937:Thymidine Kinase; D001973:Bromodeoxyuridine; D015774:Ganciclovir