Phenotypes associated with this allele

• Allele Symbol: Myh3^tm1.2Sajm
• Allele Name: targeted mutation 1.2, Sam J Mathew
• Allele ID: MGI:6695299
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Myh3^tm1.2Sajm/Myh3^tm1.2Sajm	involves: 129S1/Sv * 129S4/SvJaeSor * C57BL/6J	MGI:6695906
cn2	Myh3^tm1.2Sajm/Myh3^tm1.1Sajm Pax7^tm1(cre)Mrc/Pax7^+	involves: 129S1/Sv * 129S4/SvJaeSor * 129X1/SvJ * C57BL/6J	MGI:6695908
cn3	Myh3^tm1.2Sajm/Myh3^tm1.1Sajm Pax3^tm1(cre)Joe/Pax3^+	involves: 129S1/Sv * 129S4/SvJaeSor * C57BL/6J	MGI:6695907

Genotype
MGI:6695906

hm1

• Allelic Composition: Myh3^tm1.2Sajm/Myh3^tm1.2Sajm
• Genetic Background: involves: 129S1/Sv * 129S4/SvJaeSor * C57BL/6J

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

cellular

increased myoblast apoptosis ( J:287755 )

• at age P0

growth/size/body

decreased body weight ( J:287755 )

• low birth weight

mortality/aging

prenatal lethality, incomplete penetrance ( J:287755 )

• mice are born at about half the expected Mendelian ratio

muscle

increased myoblast apoptosis ( J:287755 )

• at age P0

abnormal muscle precursor cell morphology ( J:287755 )

• reduction in Pax7+ myogenic precursor cells and in levels of committed myoblast marker MyoD peptide in E16.5 embryos

• normal number of Pax7+ myogenic precursor cells at age P0

decreased skeletal muscle fiber diameter ( J:287755 )

• in soleus at age P0, tibialis anterior (TA) and gastrocnemius at ages P15 and P30 and EDL at P15

• in extensor digitorum longus (EDL) at ages P0 and P30

increased skeletal muscle fiber number ( J:287755 )

• in extensor digitorum longus (EDL) and soleus at age P0

decreased skeletal muscle weight ( J:287755 )

• of tibialis anterior (TA), gastrocnemius and quadriceps at ages P15 and P30

abnormal skeletal muscle fiber type ratio ( J:287755 )

• increased number of MYH7+ (MyHC-slow) fibers in hind limb at age P0 and tibialis anterior (TA) and gastrocnemius at age P15

• in extensor digitorum longus (EDL) at age P15 and tibialis anterior (TA) and gastrocnemius at age P30

Genotype
MGI:6695908

cn2

• Allelic Composition: Myh3^tm1.2Sajm/Myh3^tm1.1Sajm; Pax7^tm1(cre)Mrc/Pax7⁺
• Genetic Background: involves: 129S1/Sv * 129S4/SvJaeSor * 129X1/SvJ * C57BL/6J

muscle

abnormal muscle precursor cell morphology ( J:287755 )

• reduction in myogenic precursor marker Pax7 peptide level and 50% reduction in Pax7+ myogenic precursor cells in E16.5 embryos

• significantly reduced levels of committed myoblast markers MyoD and myogenin peptide levels and 60% reduction in MyoD+ myoblasts in E16.5 embryos

• 7x increased MyHC-slow peptide levels in E16.5 embryos

cellular

cellular phenotype ( J:287755 )

N • normal apoptosis in E16.5 embryos

Genotype
MGI:6695907

cn3

• Allelic Composition: Myh3^tm1.2Sajm/Myh3^tm1.1Sajm; Pax3^tm1(cre)Joe/Pax3⁺
• Genetic Background: involves: 129S1/Sv * 129S4/SvJaeSor * C57BL/6J

muscle

abnormal muscle precursor cell morphology ( J:287755 )

• 50% reduction in myogenic precursor marker Pax7 peptide level in E13.5 embryos

• significantly increased levels of committed myoblast markers MyoD and myogenin peptide levels in E13.5 embryos