Oligodendrocyte positioning in cerebral cortex is independent of projection neuron layering.
The factors affecting normal oligodendrocyte positioning in the cerebral cortex are unknown. Apart from the white matter, the highest numbers of oligodendrocytes in the rodent cortex are found in Layers V/VI, where the infragranular neurons normally reside. Few, if any, oligodendrocytes are normally found in the superficial cortical layers. To test whether or not this asymmetric positioning of oligodendrocytes is linked to the lamina positions of Layer V/VI projection neurons, mutant mice that cause neuronal layer inversion were examined. In three lines of mutant mice (Reeler, disabled-1, and p35) examined, representing two different genetic signaling pathways, the oligodendrocyte distribution was altered from an asymmetric to a symmetric distribution pattern. Unlike cortical neurons that are inverted in these mutant mice, the lack of oligodendrocyte inversion suggests a decoupling of the genetic mechanisms governing neuronal versus oligodendrocyte patterning. We conclude that oligodendrocyte positioning is not linked to the layer positions of V/VI projection neurons.
Tan
Seong-Seng
SS
Florey Neurosciences Institute and Centre for Neuroscience, The University of Melbourne, Parkville, Victoria, Australia. stan@florey.edu.au
Kalloniatis
Michael
M
Truong
Hue-Trung
HT
Binder
Michele D
MD
Cate
Holly S
HS
Kilpatrick
Trevor J
TJ
Hammond
Vicki E
VE
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000166:cytology* / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D008817:Mice, Mutant Strains; D008818:Mice, Neurologic Mutants; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D009836:Oligodendroglia / Q000166:cytology* / Q000378:metabolism; D010770:Phosphotransferases / Q000235:genetics; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; C492235:Cdk5r1 protein, rat; D015816:Cell Adhesion Molecules, Neuronal; C499786:Dab1 protein, rat; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D000091042:Reelin Protein; D010770:Phosphotransferases; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D012697:Serine Endopeptidases