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Allele Symbol Allele Name Allele ID |
Musktm1.1Vwi targeted mutation 1.1, Veit Witzemann MGI:3621908 |
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| Summary |
3 genotypes
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| ♀ | phenotype observed in females |
| ♂ | phenotype observed in males |
| N | normal phenotype |
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| ♀ | phenotype observed in females |
| ♂ | phenotype observed in males |
| N | normal phenotype |
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• 40% of male mice die between the second and fourth month of life
• however, female mice do not exhibit premature death
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• after 3 weeks, mice exhibit reduced muscle mass compared to wild type mice in the pelvic and scapular regions
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• muscle strength produced by single or titanic stimuli is reduced compared to in wild-type mice while the degree of fatigue remains the same
• the time to peak or contraction time and half relaxation time of a direct-evoked single twitch is prolonged compared to in wild-type muscle
• unlike in wild-type mice, the diaphragm is unable to maintain unique tentanic contractions or repetitive titanic contractions indicating reduced fatigue resistance
• the twitch to titanic ratio of the diaphragm after nerve stimulation is double wild-type
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• mice exhibit weakness of the pelvic muscle that leads to a waddling gait unlike
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• axons of the nerves innervating the diaphragm exhibit overgrowth and increased branching compared to in wild-type mice
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• axons are increased in length and extend from the main nerve trunk to the medial and/or lateral side of the diaphragm compared to in wild-type mice
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• unlike in wild-type mice, axons at the NMJs in the diaphragm exhibit sprouting and retraction bulbs and fail to form the normal Pretzel-like shaped post-synpatic structure
• as early as P0, endplates in the diaphragm NMJs are smaller and more spread out than in wild-type mice
• at P25 and P45, diaphragm neuromuscular junctions (NMJs) lack a well-defined central endplate unlike in wild-type mice
• at P45, the NMJs of the intercostals, diaphragm and tibialis anterior exhibit altered post-synaptic structures compared to in wild-type mice
• at P120, soleus NMJs exhibit few junctional folds, the distance between the post-synaptic membrane and myofibril compartment is reduced compared to in wild-type mice, mitochondria invade the subsynpatic space, subsynaptic nuclei disappear, and in many cases the sole plate is abolished
• however, extensor digitorum longus NMJs are normal
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• the amplitude of endplate potentials is 76% of wild-type
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• the mean peak frequency of miniature end plate potential of the diaphragm is reduced compared to in wild-type diaphragms
• however, the amplitudes of miniature end plate potentials is normal
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• in a rotarod test, the latency to fall is half of wild-type
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• mice exhibit a progressive loss of grip strength beginning at P21 and reaching a 30% reduction by P60 compared to wild-type mice
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• mice develop a waddling gait
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• after 3 weeks, mice exhibit deformation of the backbone and increasing kyphosis unlike in wild-type mice
• at P45, mice exhibit curvatures of the spine in the thoracic and lumbar vertebrae
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• by 2 months of age mice weigh 75% of wild-type
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• axons of the nerves innervating the diaphragm exhibit overgrowth and increased branching compared to in wild-type mice
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Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
| congenital myasthenic syndrome 9 | DOID:0110670 |
OMIM:616325 |
J:141024 | |
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| ♀ | phenotype observed in females |
| ♂ | phenotype observed in males |
| N | normal phenotype |
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• die before P30
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• at around 2 to 3 weeks of age, develop severe muscle weakness with impaired mobility and difficulty breathing, eating, and drinking
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• in older mice, phrenic nerve innervation is seen outside the central band of the diaphragm muscle
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• from P20 on, endplates in the diaphragm show decreased acetylcholine receptor densities and begin to disintegrate
• after P20 neuromuscular junction endplates are seen outside the central band where they are normally confined
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• grip strength from P12 onwards does not increase, unlike in wild-type mice
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• normal weight gain until about 3 to 4 weeks of age then weight gain stops and weight loss is seen
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Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
| congenital myasthenic syndrome 9 | DOID:0110670 |
OMIM:616325 |
J:106867 | |
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO) |
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last database update 04/16/2024 MGI 6.23 |
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