title: Bilateral subcortical heterotopia with partial callosal agenesis in a mouse mutant.
abstract: Cognition and behavior depend on the precise placement and interconnection of complex ensembles of neurons in cerebral cortex. Mutations that disrupt migration of immature neurons from the ventricular zone to the cortical plate have provided major insight into mechanisms of brain development and disease. We have discovered a new and highly penetrant spontaneous mutation that leads to large nodular bilateral subcortical heterotopias with partial callosal agenesis. The mutant phenotype was first detected in a colony of fully inbred BXD29 mice already known to harbor a mutation in Tlr4. Neurons confined to the heterotopias are mainly born in midgestation to late gestation and would normally have migrated into layers 2-4 of overlying neocortex. Callosal cross-sectional area and fiber number are reduced up to 50% compared with coisogenic wildtype BXD29 substrain controls. Mutants have a pronounced and highly selective defect in rapid auditory processing. The segregation pattern of the mutant phenotype is most consistent with a two-locus autosomal recessive model, and selective genotyping definitively rules out the Tlr4 mutation as a cause. The discovery of a novel mutation with strong pleiotropic anatomical and behavioral effects provides an important new resource for dissecting molecular mechanisms and functional consequences of errors of neuronal migration.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. grosen@bidmc.harvard.edu
authors.forename: G D
authors.initials: GD
authors.lastname: Rosen
authors.forename: N G
authors.initials: NG
authors.lastname: Azoulay
authors.forename: E G
authors.initials: EG
authors.lastname: Griffin
authors.forename: A
authors.initials: A
authors.lastname: Newbury
authors.forename: L
authors.initials: L
authors.lastname: Koganti
authors.forename: N
authors.initials: N
authors.lastname: Fujisaki
authors.forename: E
authors.initials: E
authors.lastname: Takahashi
authors.forename: P E
authors.initials: PE
authors.lastname: Grant
authors.forename: D T
authors.initials: DT
authors.lastname: Truong
authors.forename: R H
authors.initials: RH
authors.lastname: Fitch
authors.forename: L
authors.initials: L
authors.lastname: Lu
authors.forename: R W
authors.initials: RW
authors.lastname: Williams
mesh_terms: D000161:Acoustic Stimulation; D061085:Agenesis of Corpus Callosum / Q000150:complications* / Q000235:genetics*; D000704:Analysis of Variance; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D008297:Male; D018782:Maze Learning / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity / Q000235:genetics; D009154:Mutation / Q000235:genetics; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009421:Nervous System Malformations / Q000150:complications* / Q000235:genetics*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000235:genetics
chemical_list: C000624101:Cux1 protein, mouse; D018398:Homeodomain Proteins; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D001973:Bromodeoxyuridine