title: Mutations of EFHC1, linked to juvenile myoclonic epilepsy, disrupt radial and tangential migrations during brain development.
abstract: Heterozygous mutations in Myoclonin1/EFHC1 cause juvenile myoclonic epilepsy (JME), the most common form of genetic generalized epilepsies, while homozygous F229L mutation is associated with primary intractable epilepsy in infancy. Heterozygous mutations in adolescent JME patients produce subtle malformations of cortical and subcortical architecture, whereas homozygous F229L mutation in infancy induces severe brain pathology and death. However, the underlying pathological mechanisms for these observations remain unknown. We had previously demonstrated that EFHC1 is a microtubule-associated protein (MAP) involved in cell division and radial migration during cerebral corticogenesis. Here, we show that JME mutations, including F229L, do not alter the ability of EFHC1 to colocalize with the centrosome and the mitotic spindle, but act in a dominant-negative manner to impair mitotic spindle organization. We also found that mutants EFHC1 expression disrupted radial and tangential migration by affecting the morphology of radial glia and migrating neurons. These results show how Myoclonin1/EFHC1 mutations disrupt brain development and potentially produce structural brain abnormalities on which epileptogenesis is established.
authors.affiliation: GIGA-Neurosciences, University of Liège, Liège, Belgium.
authors.forename: Laurence
authors.initials: L
authors.lastname: de Nijs
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wolkoff
authors.forename: Bernard
authors.initials: B
authors.lastname: Coumans
authors.forename: Antonio V
authors.initials: AV
authors.lastname: Delgado-Escueta
authors.forename: Thierry
authors.initials: T
authors.lastname: Grisar
authors.forename: Bernard
authors.initials: B
authors.lastname: Lakaye
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology* / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D051379:Mice; D009154:Mutation; D020190:Myoclonic Epilepsy, Juvenile / Q000196:embryology* / Q000235:genetics*; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D021381:Protein Transport; D051381:Rats; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; C489648:EFHC1 protein, human