Phenotypes associated with this allele

• Allele Symbol: Mag^tm1Mtg
• Allele Name: targeted mutation 1, Dirk Montag
• Allele ID: MGI:2384092
• Summary: 5 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Mag^tm1Mtg/Mag^tm1Mtg	B6N.129S2-Mag^tm1Mtg	MGI:5902383
hm2	Mag^tm1Mtg/Mag^tm1Mtg	either: (involves: 129S2/SvPas) or (involves: 129S2/SvPas * C57BL/6)	MGI:4355931
hm3	Mag^tm1Mtg/Mag^tm1Mtg	involves: 129S2/SvPas	MGI:4355932
cn4	Cmtm6^tm1c(EUCOMM)Wtsi/Cmtm6^tm1c(EUCOMM)Wtsi Mag^tm1Mtg/Mag^tm1Mtg Tg(Dhh-cre)1Mejr/0	involves: 129S2/SvPas * 129S4/SvJaeSor * C57BL/6N * FVB/N	MGI:6511254
cx5	Mag^tm1Mtg/Mag^tm1Mtg Ncam1^tm1Cgn/Ncam1^tm1Cgn	involves: 129P2/OlaHsd * 129S2/SvPas	MGI:4355933

Genotype
MGI:5902383

hm1

• Allelic Composition: Mag^tm1Mtg/Mag^tm1Mtg
• Genetic Background: B6N.129S2-Mag^tm1Mtg

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

nervous system

tomacula ( J:236408 )

♂

dysmyelination ( J:236408 )

♂ • hypomyelination with swellings of the inner tongue of myelin

Genotype
MGI:4355931

hm2

• Allelic Composition: Mag^tm1Mtg/Mag^tm1Mtg
• Genetic Background: either: (involves: 129S2/SvPas) or (involves: 129S2/SvPas * C57BL/6)

nervous system

nervous system phenotype ( J:19475 )

N • despite abnormalities in myelin, no defects in nerve conduction are detected

abnormal axon morphology ( J:19475 )

• unlike in wild-type controls, very few axons have periaxonal cytoplasmic collars that extend more than half the circumference of the myelin sheath

abnormal myelin sheath morphology ( J:19475 )

• at 2 - 4 months of age in the optic nerve, oligodendrocytes contain regions with cytoplasm within the compact myelin that upon closer examination reveal more than one concentric myelin sheath associated with an axon

• some axons are associated with up to 4 individual myelin sheaths

abnormal myelination ( J:19475 )

• at P10 and P11 in the retinal ganglion, fewer myelinated axons are seen suggesting a delay in myelination

Genotype
MGI:4355932

hm3

• Allelic Composition: Mag^tm1Mtg/Mag^tm1Mtg
• Genetic Background: involves: 129S2/SvPas

nervous system

abnormal oligodendrocyte morphology ( J:38760 )

• at 8 and 9 months of age in the spinal cord, oligodendrocyte processes are enlarged and contain myelin like vesicles and multivesiculated bodies

• in severely enlarged processes amorphous and granular osmiophilic material appeared side by side with vesicular inclusions or mitochondria

abnormal Schwann cell morphology ( J:106609 )

• at 8 months of age, Schwann cells with contorted myelin sheaths or myelin debris and Schwann cells not in contact with axons are seen

• at 8 months of age, Schwann cells occasionally contain degenerating myelin and axonal debris

abnormal axon morphology ( J:38760 , J:78646 , J:106609 , J:296495 )

• at 8 and 9 months of age in the spinal cord, scattered thickened myelinated fibers with moderately osmiophillic material between the myelin sheath and the axon are seen (J:38760)

• at 26 weeks of age, onion bulb like structures are seen in the femoral quadriceps nerve (J:78646)

• at 8 months of age, onion bulbs consisting of myelinating Schwann cells and concentrically arranged Schwann cell processes each covered by a basal lamina are seen (J:106609)

• decreased diameter of sciatic nerve axons (J:296495)

axon degeneration ( J:78646 , J:106609 )

• at 26 weeks of age, degenerating axons and degenerating myelin are seen in the femoral quadriceps nerve (J:78646)

• however, at 26 weeks of age very few degenerating fibers are seen in the cutaneous (saphenous) nerve branch (J:78646)

• at 8 months of age, many axons show signs of degeneration (J:106609)

• degenerating axons have small diameters and high electron density or axoplasm containing numerous small vesicles and/or cellular debris (J:106609)

demyelination ( J:106609 )

• presence of onion bulb structures indicates demyelination induced Schwann cell proliferation

Genotype
MGI:6511254

cn4

• Allelic Composition: Cmtm6^{tm1c(EUCOMM)Wtsi}/Cmtm6^{tm1c(EUCOMM)Wtsi}; Mag^tm1Mtg/Mag^tm1Mtg; Tg(Dhh-cre)1Mejr/0
• Genetic Background: involves: 129S2/SvPas * 129S4/SvJaeSor * C57BL/6N * FVB/N

nervous system

abnormal axon morphology ( J:296495 )

• increased diameter of sciatic nerve axons

Genotype
MGI:4355933

cx5

• Allelic Composition: Mag^tm1Mtg/Mag^tm1Mtg; Ncam1^tm1Cgn/Ncam1^tm1Cgn
• Genetic Background: involves: 129P2/OlaHsd * 129S2/SvPas

nervous system

abnormal axon morphology ( J:78646 )

• at 4 weeks of age, onion bulb like structures are seen in the pectineus and quadriceps nerves

abnormal myelin sheath morphology ( J:78646 )

• at 8 weeks of age in single fiber preparations many fibers show signs of myelin degeneration

• degeneration is preferentially associated with the paranodal regions of the fibers

axon degeneration ( J:78646 )

• at 4 weeks of age, degenerating axons and degenerating myelin are seen in the femoral quadriceps nerve

• at 8 weeks of age the number of abnormal axons is increased compared to mice at 4 weeks of age