Phenotypes associated with this allele

• Allele Symbol: Limch1^em1Coop
• Allele Name: endonuclease-mediated mutation 1, Thomas A Cooper
• Allele ID: MGI:7580925
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Limch1^em1Coop/Limch1^em1Coop	FVB-Limch1^em1Coop	MGI:7595837

Genotype
MGI:7595837

hm1

• Allelic Composition: Limch1^em1Coop/Limch1^em1Coop
• Genetic Background: FVB-Limch1^em1Coop

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

behavior/neurological

decreased grip strength ( J:336773 )

• adult mice show a significantly decreased grip strength with a reduction of 31% and 29% in male and female mice, respectively

muscle

muscle phenotype ( J:336773 )

N • mice show no major changes in myofiber diameter, centralized nuclei, or fibrotic scarring in skeletal muscle tissue at 10-12 weeks and at 1 yr of age; muscle weights divided by tibia length are normal in gastrocnemius, quadriceps and soleus muscle

abnormal skeletal muscle fiber morphology ( J:336773 )

• isolated flexor digitorum brevis (FDB) myofibers show disturbed LIMCH1 localization: LIMCH1 is primarily localized throughout the sarcoplasm of the myofiber rather than preferentially localizing to the sarcolemma as in wild-type myofibers

impaired skeletal muscle contractility ( J:336773 )

• maximum force production is significantly reduced in both extensor digitorum longus (EDL, fast-twitch fibers) and soleus (slow-twitch fibers), with a stronger reduction in force generation seen at higher frequencies

• following an ex vivo isometric twitch, the rate of contraction (dp/dt) in EDL muscle is significantly lower than that in wild-type controls

• rate of contraction is not significantly altered in soleus muscle

• after repeated stimulation, fatigue and recovery remain normal in both EDL and soleus tissue

impaired muscle relaxation ( J:336773 )

• following an ex vivo isometric twitch, the rate of relaxation (-dp/dt) in EDL muscle is significantly lower than that in wild-type controls

• however, the rate of relaxation is not significantly altered in soleus muscle

muscle weakness ( J:336773 )

• adult mice exhibit significant skeletal muscle weakness

• however, no muscle wasting is noted based on muscle weights

homeostasis/metabolism

abnormal calcium ion homeostasis ( J:336773 )

• intracellular calcium handling is disrupted in skeletal muscle; average peak Fura ratio (360/380 nm) is significantly lower in both male- and female-derived flexor digitorum brevis (FDB) myofibers stimulated with a 1 Hz twitch, a 20 Hz tetanus, or a 100 Hz tetanus than in similarly stimulated wild-type myofibers

• however, T-tubule-related proteins remain structurally intact