Phenotypes Associated with This Genotype

Genotype
MGI:2183424

• Allelic Composition: Atoh1^tm2Hzo/Atoh1^tm2Hzo
• Genetic Background: Not Specified

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

mortality/aging

neonatal lethality, complete penetrance ( J:60393 , J:155760 )

• animals die shortly after birth (J:60393)

• reported to make occasional gasps after birth (J:155760)

• unresponsive by 30-45 minutes after birth (J:155760)

hearing/vestibular/ear

absent cochlear hair cells ( J:55694 )

absent vestibular hair cells ( J:55694 )

• hair cells were absent from utricles and cochlea

homeostasis/metabolism

cyanosis ( J:60393 )

respiratory system

decreased pulmonary respiratory rate ( J:155760 )

• diaphragmatic electromyograms indicate slow and variable respiratory rhythms involving the phrenic nerve

• rhythms also slow when recorded from hypoglossal and C4 nerves when the diaphragm is not part of the experimental preparation

• glutamatergic modulators such as dihydrokainic acid and ampakine (CX546) restore near normal rhythm and pattern in expermimental preparations

• substance P increases respiratory rhythm but does not restore normal frequency or pattern

• norepinephrin establishes a similar slow, regular pace in both mutant and control experimental preparations

respiratory failure ( J:60393 )

• animals do not breathe after birth

nervous system

nervous system phenotype ( J:60393 )

N • normal hindbrain: normal nucleus tractus solitarus, nucleus ambiguus, dorsal vagus nucleus and trigeminal ganglion

absent cochlear hair cells ( J:55694 )

absent vestibular hair cells ( J:55694 )

• hair cells were absent from utricles and cochlea

abnormal hindbrain development ( J:105186 )

• in null embryos, certain nuclei of the rostrolateral region of the hindbrain that originate in the cerebellar rhombic lip fail to form; nuclei such as the pontine nuclei and the external granule layer do not seem to form in the rostrolateral hindbrain but are present at more caudal positions in mutant brains

absent cerebellar foliation ( J:60393 )

abnormal cerebellum external granule cell layer morphology ( J:60393 )

• absent external granule layer: migrating granule cells absent as early as E14 in rhombic lip

abnormal cerebellar Purkinje cell layer ( J:60393 )

• disorganized and cells localized at periphery of cerebellum

small cerebellum ( J:60393 )