Affiliation:
1. Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences
2. Laboratory for Neurogenetics, RIKEN Center for Brain Science
3. Department of Physiology, Nippon Medical School
4. Laboratory for Behavioral Genetics, RIKEN Center for Brain Science
Abstract
Expressions of voltage-gated sodium channels Nav1.1 and Nav1.2, encoded by SCN1A and SCN2A genes, respectively, have been reported to be mutually exclusive in most brain regions. In juvenile and adult neocortex, Nav1.1 is predominantly expressed in inhibitory neurons while Nav1.2 is in excitatory neurons. Although a distinct subpopulation of layer V (L5) neocortical excitatory neurons were also reported to express Nav1.1, their nature has been uncharacterized. In hippocampus, Nav1.1 has been proposed to be expressed only in inhibitory neurons. By using newly generated transgenic mouse lines expressing Scn1a promoter-driven green fluorescent protein (GFP), here we confirm the mutually exclusive expressions of Nav1.1 and Nav1.2 and the absence of Nav1.1 in hippocampal excitatory neurons. We also show that Nav1.1 is expressed in inhibitory and a subpopulation of excitatory neurons not only in L5 but all layers of neocortex. By using neocortical excitatory projection neuron markers including FEZF2 for L5 pyramidal tract (PT) and TBR1 for layer VI (L6) cortico-thalamic (CT) projection neurons, we further show that most L5 PT neurons and a minor subpopulation of layer II/III (L2/3) cortico-cortical (CC) neurons express Nav1.1 while the majority of L6 CT, L5/6 cortico-striatal (CS), and L2/3 CC neurons express Nav1.2. These observations now contribute to the elucidation of pathological neural circuits for diseases such as epilepsies and neurodevelopmental disorders caused by SCN1A and SCN2A mutations.
Funder
Japan Society for the Promotion of Science
RIKEN Center for Brain Science
Japan Agency for Medical Research and Development
Ministry of Education, Culture, Sports, Science and Technology
Takeda Science Foundation
Kiyokun Foundation
Japan Epilepsy Research Foundation
Publisher
eLife Sciences Publications, Ltd
Subject
General Immunology and Microbiology,General Biochemistry, Genetics and Molecular Biology,General Medicine,General Neuroscience
Cited by
2 articles.
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