Phenotypes Associated with This Genotype

Genotype
MGI:3654907

• Allelic Composition: Myog^tm1Whk/Myog^tm1Whk
• Genetic Background: involves: 129S7/SvEvBrd

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

cellular

abnormal myoblast differentiation ( J:22984 )

• at E12.5 desmin staining is weaker and myosin heavy polypeptide staining is absent suggesting a delay in myoblast differentiation

• at E14.5 myoblasts appear to persist in muscle forming regions suggesting incomplete differentiation

mortality/aging

neonatal lethality, complete penetrance ( J:110733 )

muscle

abnormal laryngeal muscle morphology ( J:110733 )

• undetectable

abnormal muscle development ( J:22984 )

abnormal myogenesis ( J:22984 )

• after E15.5 somitic muscle forming regions are greatly reduced in mass, myofibers are more diffuse and stain less intensely for myosin heavy polypeptide and at E16.5 myofiber numbers are reduced compared to wild-type

abnormal myoblast differentiation ( J:22984 )

• at E12.5 desmin staining is weaker and myosin heavy polypeptide staining is absent suggesting a delay in myoblast differentiation

• at E14.5 myoblasts appear to persist in muscle forming regions suggesting incomplete differentiation

thin diaphragm muscle ( J:110733 )

• thin and fibrous but intact

muscle hypoplasia ( J:110733 , J:22984 )

• at E18.5 muscles in the back, ventral-lateral body wall, and forelimb have far fewer muscle fibers compared to control littermates; however, the ratio of fast to slow fibers is similar to controls and all muscle groups that make up the crural region of the hindlimb are present despite the reduction in fiber number (J:22984)

growth/size/body

abnormal laryngeal muscle morphology ( J:110733 )

• undetectable

respiratory system

abnormal laryngeal muscle morphology ( J:110733 )

• undetectable

abnormal lung development ( J:110733 )

• at E20, lungs appear to have arrested at the canalicular stage and retain cuboidal respiratory epithelium

• at E20, increased apoptosis is seen primarily in the bronchial or mesenchymal cells; however no change in apoptosis is seen in the heart or liver

pulmonary hypoplasia ( J:110733 )

• ratio of wet lung weight to body weight is reduced at E14, E17, and E20; however lung lobe structure is similar to wild-type

• at E14, intrathoracic spaces are about 30% smaller compared to age-matched littermates

• at E14 and E17, BrdU and PCNA labeling indicate a decrease in proliferation and proliferation rates in the mesenchymal and epithelial compartments are similar unlike in control littermates

• DNA content at term (E20) is reduced by about 20% compared to control littermates

respiratory failure ( J:110733 )

• no respiratory movements

behavior/neurological

abnormal reflex ( J:110733 )

• lack withdrawal reflexes at E17, E19, and E20 (full term)

no spontaneous movement ( J:110733 )

homeostasis/metabolism

cyanosis ( J:110733 )

• develops within seconds of birth

skeleton

kyphosis ( J:110733 )

embryo

embryo phenotype ( J:110733 )

N • amniotic fluid volume appears normal