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Updated: Jun 21, 2026
Induction of Protein Deletion Through In Utero Electroporation to Define Deficits in Neuronal Migration in Transgenic Models
Published on: January 12, 2015
Cortical migration defects in mice expressing A-RAF from the B-RAF locus
Guadalupe Camarero1, Oleg Yu Tyrsin, Chaomei Xiang
1Institut für Medizinische Strahlenkunde und Zellforschung, Bayerische Julius-Maximilians-Universität, Versbacher-Str. 5, D-97078 Würzburg, Germany.
Abstract:
We have previously shown that mice lacking the protein kinase B-RAF have defects in both neural and endothelial cell lineages and die around embryonic day 12 (E12). To delineate the function of B-RAF in the brain, B-RAF KIN/KIN mice lacking B-RAF and expressing A-RAF under the control of the B-RAF locus were created. B-RAF KIN/KIN embryos displayed no vascular defects, no endothelial and neuronal apoptosis, or gross developmental abnormalities, and a significant proportion of these animals survived for up to 8 weeks. Cell proliferation in the neocortex was reduced from E14.5 onwards. Newborn cortical neurons were impaired in their migration toward the cortical plate, causing a depletion of Brn-2-expressing pyramidal neurons in layers II, III, and V of the postnatal cortex. Our data reveal that B-RAF is an important mediator of neuronal survival, migration, and dendrite formation and that A-RAF cannot fully compensate for these functions.
Insights
Protein kinase B-RAF is crucial for brain development, specifically neuronal survival and migration. Its absence impairs neuron development, and the related A-RAF protein cannot fully compensate for these vital functions.
Area of Science:
- Neuroscience
- Molecular Biology
- Developmental Biology
Background:
- Protein kinase B-RAF (BRAF) is essential for embryonic development, with BRAF-deficient mice exhibiting severe defects and early lethality.
- Previous studies indicated BRAF's role in neural and endothelial cell lineages.
Purpose of the Study:
- To investigate the specific function of BRAF in brain development.
- To determine if A-RAF can compensate for the loss of BRAF function in the central nervous system.
Main Methods:
- Generation of B-RAF KIN/KIN mice, which lack BRAF but express A-RAF under the BRAF locus control.
- Analysis of embryonic and postnatal development, focusing on vascularization, apoptosis, cell proliferation, and neuronal migration.
Main Results:
- B-RAF KIN/KIN mice survived beyond embryonic day 12, showing no vascular defects or widespread apoptosis.
- Reduced neocortical cell proliferation and impaired neuronal migration were observed from E14.5 onwards.
- A significant depletion of Brn-2-expressing pyramidal neurons in specific cortical layers was noted in postnatal brains.
Conclusions:
- BRAF is a critical mediator of neuronal survival, migration, and dendrite formation in the developing brain.
- A-RAF cannot fully compensate for the loss of BRAF's essential functions in neurodevelopment.
- These findings highlight the indispensable role of BRAF in establishing proper cortical architecture.
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