Phenotypes associated with this allele

• Allele Symbol: Nefm^tm1Mvr
• Allele Name: targeted mutation 1, Mala V Rao
• Allele ID: MGI:2686958
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Nefm^tm1Mvr/Nefm^tm1Mvr	involves: 129S1/Sv * 129X1/SvJ	MGI:3842788
hm2	Nefm^tm1Mvr/Nefm^tm1Mvr	involves: 129S1/Sv * 129X1/SvJ * C57BL/6J	MGI:2686964
cx3	Nefh^tm2Dwc/Nefh^tm2Dwc Nefm^tm1Mvr/Nefm^tm1Mvr	involves: 129S1/Sv * 129X1/SvJ	MGI:3842789

Genotype
MGI:3842788

hm1

• Allelic Composition: Nefm^tm1Mvr/Nefm^tm1Mvr
• Genetic Background: involves: 129S1/Sv * 129X1/SvJ

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

nervous system

nervous system phenotype ( J:87156 )

N • despite neurofilament abnormalities, no differences in recovery from crush injury of the sciatic nerve are detected

abnormal neuron differentiation ( J:87156 )

• large myelinated fibers fail to grow in the time span between 2 and 6 months of age

abnormal axon morphology ( J:87156 )

• in ventral root axons both large and small classes of myelinated fibers have smaller diameters compared to the same class in controls

• nearest neighbor distances for neurofilaments are reduced compared to wild-type controls at 2 and 6 months of age

• axoplasm is less well organized with increased neurofilament clustering, increased variability in microtubule content, and increased mitochondrial content in the proximal axonal segments

abnormal action potential ( J:87156 )

• slower propagation of action potential in the sciatic nerve at 5 - 6 months of age

behavior/neurological

behavior/neurological phenotype ( J:87156 )

N • despite defects in axon morphology and physiology, no locomotor abnormalities are detected

cellular

abnormal neuron differentiation ( J:87156 )

• large myelinated fibers fail to grow in the time span between 2 and 6 months of age

Genotype
MGI:2686964

hm2

• Allelic Composition: Nefm^tm1Mvr/Nefm^tm1Mvr
• Genetic Background: involves: 129S1/Sv * 129X1/SvJ * C57BL/6J

nervous system

nervous system phenotype ( J:87157 )

N • despite neurofilament abnormalities, average rate of neurofilament transport is not different from controls

abnormal neuron differentiation ( J:87157 )

• severe inhibition of axonal radial growth between 2 and 6 months of age in motor axons and sensory axons

• however, no change in the total number of axons is detected

abnormal axon morphology ( J:87157 )

• about a 2 fold increase in total microtubule number

• increase in neurofilament density and decrease in nearest neighbor distances in motor axons

• crossbridges between neurofilaments are mostly short with fewer fine long crossbridges present

cellular

abnormal neuron differentiation ( J:87157 )

• severe inhibition of axonal radial growth between 2 and 6 months of age in motor axons and sensory axons

• however, no change in the total number of axons is detected

Genotype
MGI:3842789

cx3

• Allelic Composition: Nefh^tm2Dwc/Nefh^tm2Dwc; Nefm^tm1Mvr/Nefm^tm1Mvr
• Genetic Background: involves: 129S1/Sv * 129X1/SvJ

nervous system

nervous system phenotype ( J:87156 )

N • despite neurofilament abnormalities, no differences in recovery from crush injury of the sciatic nerve are detected

abnormal axon morphology ( J:87156 )

• at 2 months of age the number of motor axons with cross sections greater than 2 um is reduced by about 50% compared to mice homozygous for Nefm^tm1Mvr alone

• but by 6 months of age the size distribution of axons is indistinguishable from that of mice homozygous for Nefm^tm1Mvr alone

• nearest neighbor distances for neurofilaments are reduced compared to wild-type and single homozygous controls

• crossbridges spanning between neurofilaments are almost completely absent and neurofilaments are more curved forming wavy, irregular arrays

• axoplasm is less well organized with increased neurofilament clustering, increased variability in microtubule content, and increased mitochondrial content in the proximal axonal segments

abnormal action potential ( J:87156 )

• slower propagation of action potential in the sciatic nerve at 5 - 6 months of age

behavior/neurological

behavior/neurological phenotype ( J:87156 )

N • despite defects in axon morphology and physiology, no locomotor abnormalities are detected