Phenotypes associated with this allele

• Allele Symbol: Mybpc2^tm1Ssad
• Allele Name: targeted mutation 1, Sakthivel Sadayappan
• Allele ID: MGI:7331608
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Mybpc2^tm1Ssad/Mybpc2^tm1Ssad	involves: C57BL/6 * FVB/N	MGI:7662526

Genotype
MGI:7662526

hm1

• Allelic Composition: Mybpc2^tm1Ssad/Mybpc2^tm1Ssad
• Genetic Background: involves: C57BL/6 * FVB/N

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

behavior/neurological

decreased grip strength ( J:309473 )

• maximum grip strength is reduced

impaired exercise endurance ( J:309473 )

• treadmill running times are reduced

muscle

abnormal extensor digitorum longus morphology ( J:309473 )

• slight decrease in the percentage of EDL type I fibers

abnormal skeletal muscle fiber morphology ( J:309473 )

• EDL muscle shows reduced quasi-helical ordering of the myosin heads around the thick filament backbone under resting conditions

centrally nucleated skeletal muscle fibers ( J:309473 )

• increase in central nucleation and embryonic MHC+ fibers are seen in EDL muscle, indicating muscle regeneration and/or degeneration and thus mild muscle stress or damage

• plantaris muscles exposed to mechanical overload show increased number of fibers containing central nucleation

abnormal muscle physiology ( J:309473 )

• isolated intact extensor digitorum longus (EDL) (fast-type) muscle shows decreased peak isometric tetanic force and specific force

• force-frequency analysis of isolated intact EDL muscle shows lower isometric tetanic force at both maximal and submaximal stimulation frequencies

• however, no difference in the rate of contraction is seen

• however, slow-type soleus (SOL) muscle shows normal peak isometric tetanic force and specific force and maximum isometric twitch force is normal in EDL and SOL

• EDL muscles produce less steady-state isometric force both in the absence and presence of dextran and this reduction extends to lower concentrations of activating calcium

• EDL muscles generate less maximal force at pCa4.5 and although dextran increases maximal force production, EDL muscles still produce less maximal, steady-state isometric force

• myofilament calcium sensitivity (pCa50) is reduced in EDL and EDL still shows a decrease in myofilament calcium sensitivity in response to dextran

• rate of force redevelopment following a slack and restretch test is greater in EDL fibers at submaximal calcium concentrations, however rate of force redevelopment at maximal stead-state isometric activation is similar to wild-type mice

• restoration of in vivo myofilament lattice spacing with dextran results in a greater relative increase of force generation and maximal sinusoidal stiffness in EDL muscle compared to wild-type muscle

• plantaris muscle exposed to mechanical overload is less hypertrophied after 2 weeks of overload, the number of fibers containing central nucleation is increased, and muscle shows an increased number of eMHC+ fibers and greater area occupied by fibrotic tissue, indicating maladaptation to mechanical overload

abnormal muscle contractility ( J:309473 )

• isotonic speed of EDL contraction is slower at high relative force, 60 and 80% of peak isometric tetanic force

• however, isotonic speed of contraction in SOL is normal at all ranges of applied tension

impaired skeletal muscle contractility ( J:309473 )

• EDL muscle shows a reduction in the ratio of maximal active stiffness to rigor stiffness in both the absence and presence of dextran, indicating that muscles have proportionately fewer force-producing cross-bridges during active contraction

impaired muscle relaxation ( J:309473 )

• rate of relaxation is reduced in isolated intact EDL muscle over a range of stimulation frequencies

hypotonia ( J:309473 )

• EDL muscles show less sinusoidal muscle stiffness at all levels of calcium activation in both the absence or presence of dextran

muscle weakness ( J:309473 )

• plantar flexor muscle strength, measured as maximum isometric tetanic force, is reduced

limbs/digits/tail

abnormal extensor digitorum longus morphology ( J:309473 )

• slight decrease in the percentage of EDL type I fibers

homeostasis/metabolism

impaired exercise endurance ( J:309473 )

• treadmill running times are reduced

cardiovascular system

cardiovascular system phenotype ( J:309473 )

N • mice show no differences in cardiac function or cardiac muscle mass

growth/size/body

growth/size/body region phenotype ( J:309473 )

N • mice show no gross changes in body weight and appearance