Phenotypes Associated with This Genotype

Genotype
MGI:2682062

• Allelic Composition: Ext1^tm1Yama/Ext1^tm1Yama; Tg(Nes-cre)1Kln/0
• Genetic Background: involves: 129S5/SvEvBrd * C57BL/6 * SJL

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

mortality/aging

neonatal lethality, complete penetrance ( J:86465 )

• all mice die within 1 day of birth

nervous system

abnormal axon guidance ( J:86465 )

• 60-67% of retinal axons project ectopically into the contralateral optic nerve

• axons from the cortex fail to approach the midline and instead extend ventrally unlike wild-type axons that turn to the midline and cross toward the contralateral side

• axons emerging from the external capsule extend straight toward the ventral surface of the forebrain instead of turning towards the midline to form the anterior commissure

abnormal brain development ( J:86465 )

• differentiation of the caudal midbrain and cerebellum initiated but failed to form the distinct inferior colliculus and cerebellum

abnormal brain commissure morphology ( J:86465 )

• absence of the major commissure tracts

absent corpus callosum ( J:86465 )

absent hippocampal commissure ( J:86465 )

absent anterior commissure ( J:86465 )

absent inferior colliculus ( J:86465 )

abnormal cerebral cortex morphology ( J:86465 )

• overall size and thickness is reduced

• cell proliferation in the cortex is reduced by about 30% compared with controls

thin cerebral cortex ( J:86465 )

absent olfactory bulb ( J:86465 )

absent cerebellum ( J:86465 )

cellular

abnormal axon guidance ( J:86465 )

• 60-67% of retinal axons project ectopically into the contralateral optic nerve

• axons from the cortex fail to approach the midline and instead extend ventrally unlike wild-type axons that turn to the midline and cross toward the contralateral side

• axons emerging from the external capsule extend straight toward the ventral surface of the forebrain instead of turning towards the midline to form the anterior commissure