Phenotypes associated with this allele

• Allele Symbol: Epha4^tm1Byd
• Allele Name: targeted mutation 1, Andrew W Boyd
• Allele ID: MGI:2156472
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Epha4^tm1Byd/Epha4^tm1Byd	involves: 129S1/Sv * C57BL/6	MGI:3026782
ht2	Epha4^tm1Byd/Epha4^+	involves: 129S1/Sv * C57BL/6	MGI:3694676

Genotype
MGI:3026782

hm1

• Allelic Composition: Epha4^tm1Byd/Epha4^tm1Byd
• Genetic Background: involves: 129S1/Sv * C57BL/6

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

Disruption of spinal cord architecture and the anterior commissure in Epha4^tm1Byd/Epha4^tm1Byd mice

behavior/neurological

abnormal placing response ( J:50573 )

• placing deficits of both hindlimbs

impaired limb coordination ( J:50573 )

• once mutants begin to move, there is a lack of the normal synchronous movement of each forelimb with the contralateral hindlimb

abnormal locomotor activation ( J:50573 )

• mice are hesitant in initiating locomotion

• the distance traveled by mutants in an open field test is only 30% of that in heterozygotes

abnormal gait ( J:50573 , J:67274 )

• hopping gait (J:50573)

• hopping gait (J:67274)

nervous system

nervous system phenotype ( J:87398 )

N • normal hippocampal architecture

abnormal anterior commissure morphology ( J:67274 )

• both the anterior and posterior branches of the anterior commissure are reduced in diameter, shifted ventrally, and in 6 of 13 mice fail to cross the midline

abnormal anterior commissure pars anterior morphology ( J:67274 )

abnormal anterior commissure pars posterior morphology ( J:67274 )

absent anterior commissure ( J:50573 )

• loss of the anterior commissure in 12 of 14 mutants

abnormal primary somatosensory cortex morphology ( J:115279 )

abnormal barrel cortex morphology ( J:115279 )

abnormal innervation ( J:50573 , J:115279 )

• corticospinal tract axons aberrantly cross the midline boundary of the spinal cord (J:50573)

• 43% of mice display abnormal thalamocortical (TC) projections from the ventro-posterior-medial (VPM) part of the ventro-basal nucleus (VB) to the primary somatosensory area S1, with cells located at ectopic positions with respect to the position corresponding to normal barreloid clusters (J:115279)

abnormal corticospinal tract morphology ( J:50573 , J:67274 )

• axons aberrantly cross the midline boundary of the spinal cord; in the medulla, a reduced number of axons descend into the dorsal column of the spinal cord and those axons that descend in the dorsal funiculus show an aberrant pattern of termination within the gray matter of the spinal cord (J:50573)

• in the lumbar cord, there is a reduction in the number of corticospinal axons (J:50573)

• the amount of white matter in the dorsal funiculus is reduced most prominently at the lumbar level and fibers within the dorsal funiculus re-cross the midline at the lumbar level (J:67274)

abnormal spinal cord dorsal column morphology ( J:50573 )

• dorsal funiculus is shallower in mutants than in wild-type

reduced long-term potentiation ( J:87398 )

• reduced early LTP but no significant defects of basal synaptic transmission parameters or NMDA receptor component

Genotype
MGI:3694676

ht2

• Allelic Composition: Epha4^tm1Byd/Epha4⁺
• Genetic Background: involves: 129S1/Sv * C57BL/6

nervous system

abnormal primary somatosensory cortex morphology ( J:115279 )

abnormal barrel cortex morphology ( J:115279 )

abnormal innervation ( J:115279 )

• 25% of heterozygotes show similar abnormalities in TC to homozygotes