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The Journal of Neuroscience, February 18, 2009, 29(7):2009-2021; doi:10.1523/JNEUROSCI.5025-08.2009
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Development/Plasticity/Repair
Involvement of the Cytoplasmic C-Terminal Domain of Connexin43 in Neuronal Migration
Cima Cina,1 Karen Maass,2 Martin Theis,3 Klaus Willecke,4 John F. Bechberger,1 andChristian C. Naus1 1Department of Cellular and Physiological Sciences, The Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3, 2Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, New York 13210, 3Institute of Cellular Neuroscience, University of Bonn, D-53105 Bonn, Germany, and 4Institut für Genetik, Universität Bonn, D-53117 Bonn, Germany
Correspondence should be addressed to Dr. Christian C. Naus, Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3. Email: cnaus{at}interchange.ubc.ca
During brain development, young neurons closely associate with radial glial while migrating from the ventricular zone (VZ) to the cortical plate (CP) of the neocortex. It has been shown previously that gap junctions are needed for this migration to occur properly, but the precise mechanism responsible is still in question. Here, we used Cre recombinase, driven by the nestin promoter, to conditionally knock-out a floxed coding DNA of the connexin43 (Cx43) gene in mice. Radial glia in the VZ normally express connexin43. They undergo divisions that produce neurons and astrocytes and serve as migratory guides for the daughter cells that they produce. Based on histological analysis, we suggest that removing Cx43 from radial glia alters the normal lamination of the mouse neocortex. To monitor newborn neurons during development, we introduced a plasmid containing green fluorescent protein driven by a neuronal (T
1 tubulin) promoter into the embryonic neocortex using in utero electroporation. The transfected migrating neurons remain in the VZ/intermediate zone (IZ) of the Cx43 conditional knock-out (Cx43cKO) animals, whereas in Cx43fl/fl mice, neurons migrate through the IZ into the CP, indicating that deletion of Cx43 from nestin-positive cells disrupts neuronal migration. We were able to rescue migration of Cx43cKO neurons by electroporating a cytomegalovirus–Cx43 expression plasmid into the embryonic cortex. In contrast, a C-terminal truncated form of Cx43 failed to rescue neuronal migration. In addition, Cx43K258stop mice, in which Cx43 lacks the last 125 amino acid residues of the cytoplasmic C-terminal domain, gave results similar to those seen with the Cx43cKO mice. This study illustrates that deletion of the C-terminal domain of Cx43 alters neuronal migration in the neocortex.
Key words: development; cortex; gap junction; migration; glia; neuron
Received Oct. 16, 2008; revised Dec. 15, 2008; accepted Dec. 30, 2008.
Correspondence should be addressed to Dr. Christian C. Naus, Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3. Email: cnaus{at}interchange.ubc.ca
This article has been cited by other articles:
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Physiology, August 1, 2009; 24(4): 219 - 230.
[Abstract] [Full Text] [PDF]
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