Phenotypes associated with this allele

• Allele Symbol: Enah^tm1Fbg
• Allele Name: targeted mutation 1, Frank B Gertler
• Allele ID: MGI:3056050
• Summary: 4 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Enah^tm1Fbg/Enah^tm1Fbg	involves: 129S4/SvJaeSor	MGI:3718220
cx2	Enah^tm1Fbg/Enah^tm1Fbg Evl^tm1Fbg/Evl^tm1Fbg Vasp^tm1Ref/Vasp^tm1Ref	involves: 129 * BALB/c * C57BL/6	MGI:3764997
cx3	Enah^tm1Fbg/Enah^+ Evl^tm1Fbg/Evl^tm1Fbg Vasp^tm1Ref/Vasp^tm1Ref	involves: 129 * BALB/c * C57BL/6	MGI:3764998
cx4	Enah^tm1Fbg/Enah^tm1Fbg Pfn1^tm1Wit/Pfn1^+	involves: 129S4/SvJae	MGI:3718223

Genotype
MGI:3718220

hm1

• Allelic Composition: Enah^tm1Fbg/Enah^tm1Fbg
• Genetic Background: involves: 129S4/SvJaeSor

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

growth/size/body

decreased body size ( J:53259 )

• smaller than their wild-type or heterozygous littermates until adulthood

behavior/neurological

decreased locomotor activity ( J:53259 )

• reduced activity in home cage

nervous system

abnormal axon guidance ( J:53259 )

• fibers in the corpus callosum appeared to reach a point just medial to the cingulum bundle but failed to project medially and cross the midline

• most of the fibers formed dense neuromas

abnormal brain commissure morphology ( J:53259 )

• defects in midline fiber crossing in the pons

• no defects were observed in other commissures, including spinal motor neuron tracts, or in cortical lamination

absent corpus callosum ( J:53259 )

• observed in 11 out of 20 homozygous mutant mice but was never observed in 20 littermate control animals

• the defects is not from an effect of genetic background of 129sv strain

abnormal hippocampal commissure morphology ( J:53259 )

• fibers of the hippocampal commissure are abnormal

• instead of crossing contralaterally, they appeared to reach the midline and project ipsilaterally

• in more caudal sections hippocampal commissure fibers crossed the midline

cellular

abnormal axon guidance ( J:53259 )

• fibers in the corpus callosum appeared to reach a point just medial to the cingulum bundle but failed to project medially and cross the midline

• most of the fibers formed dense neuromas

Genotype
MGI:3764997

cx2

• Allelic Composition: Enah^tm1Fbg/Enah^tm1Fbg; Evl^tm1Fbg/Evl^tm1Fbg; Vasp^tm1Ref/Vasp^tm1Ref
• Genetic Background: involves: 129 * BALB/c * C57BL/6

mortality/aging

lethality throughout fetal growth and development, complete penetrance ( J:127447 )

• mice die between E16.5 and P0 with a number of defects including intraamniotic hemorrhage, hydrops fetalis and frequent exencephaly

nervous system

abnormal radial glial cell morphology ( J:127447 )

• aberrant extensions of radial processes into ectopic growths are observed

abnormal cortical intermediate zone morphology ( J:127447 )

• mice lack uDTI staining in the intermediate zone (IZ) indicating an absence of organized axon tracts

• the IZ is thinner than in wild-type mice

• IZ cortices are nearly devoid of neurofilament protein + axons Tau-1 staining is reduced

abnormal cortical plate morphology ( J:127447 )

• the cortices show cortical neurons pouring through gaps in the pial membrane and spreading tangentially within the subarachnoid space compared to the well organized cortical plate and intact pial membrane in wild-type mice

• however, laminin staining surrounding ectopias is normal and in regions without ectopias cortical plate architecture is preserved

hydrocephaly ( J:127447 )

• mice display hydrocephalus ex vacuo

enlarged brain ventricles ( J:127447 )

• at E18.5, mice display enlarged ventricle size

abnormal brain white matter morphology ( J:127447 )

• all cortical fiber tracts are missing from the brain, including all major forebrain commissures and the internal capsule

absent brain internal capsule ( J:127447 )

abnormal brain pia mater morphology ( J:127447 )

• gaps in the pial membrane allow spread of cortical neurons into the subarachnoid space

abnormal subarachnoid space morphology ( J:127447 )

• contains ectopic cortical neurons

exencephaly ( J:127447 )

• between E16.5 and P0, mice frequently display exenchephaly

abnormal neurite morphology ( J:127447 )

• after 48 hours in culture, 74% of neuritis are at stage 2 of neuritogenesis with only 2% at stage 3 compared to 10% of wild-type cells at stage 1 and 69% at stage 3

• however, axonal polarization is normal

ectopic cortical neuron ( J:127447 )

• at E18.5, mice exhibit cortical ectopias

homeostasis/metabolism

hydrops fetalis ( J:127447 )

• between E16.5 and P0

cardiovascular system

hemorrhage ( J:127447 )

• between E16.5 and P0 mice exhibit intraaminotic hemorrhage

cellular

abnormal radial glial cell morphology ( J:127447 )

• aberrant extensions of radial processes into ectopic growths are observed

Genotype
MGI:3764998

cx3

• Allelic Composition: Enah^tm1Fbg/Enah⁺; Evl^tm1Fbg/Evl^tm1Fbg; Vasp^tm1Ref/Vasp^tm1Ref
• Genetic Background: involves: 129 * BALB/c * C57BL/6

mortality/aging

lethality during fetal growth through weaning, incomplete penetrance ( J:127447 )

• while mice are present at E16.5, fewer than expected are recovered at P10

Genotype
MGI:3718223

cx4

• Allelic Composition: Enah^tm1Fbg/Enah^tm1Fbg; Pfn1^tm1Wit/Pfn1⁺
• Genetic Background: involves: 129S4/SvJae

mortality/aging

perinatal lethality, complete penetrance ( J:53259 )

• no viable animals of expected genotype from double heterozygous cross

• present in expected Mendelian frequencies at E9.5 and E16

embryo

decreased embryo size ( J:53259 )

• at E9.5

incomplete rostral neuropore closure ( J:53259 )

• cephalic neural tube failed to close in half of embryo

growth/size/body

decreased embryo size ( J:53259 )

• at E9.5

nervous system

incomplete rostral neuropore closure ( J:53259 )

• cephalic neural tube failed to close in half of embryo

anencephaly ( J:53259 )

• at E16.5 in 1 of 9 embryos

exencephaly ( J:53259 )

• at E16.5 in 4 of 9 embryos