Phenotypes associated with this allele

• Allele Symbol: Nkx2-9^tm1Hha
• Allele Name: targeted mutation 1, Hans-Henning Arnold
• Allele ID: MGI:2655862
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Nkx2-9^tm1Hha/Nkx2-9^tm1Hha	involves: 129/Sv * C57BL/6	MGI:2655875

Genotype
MGI:2655875

hm1

• Allelic Composition: Nkx2-9^tm1Hha/Nkx2-9^tm1Hha
• Genetic Background: involves: 129/Sv * C57BL/6

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

mortality/aging

mortality/aging ( J:81765 )

N • homozygotes are viable and fertile with no overt morphological or behavioral phenotype

nervous system

abnormal axon guidance ( J:102358 )

• at E11, dorsally directed spinal accessory motor neuron axons reach the lateral exit points but fail to exit the spinal cord at cervical levels; in contrast, normal axon projection and exit is noted at hindbrain levels

abnormal motor neuron morphology ( J:81765 )

• homozygotes show normal distribution of neuronal progenitor cells and differentiated neurons in the spinal cord, with the exception of a few motoneurons occasionally found within the Nkx2-2 domain of the neural tube at hindlimb level

increased motor neuron number ( J:81765 )

• at E10.5, homozygotes exhibit a 60-70% increase in the number of somatic motoneurons of the median motor column but show a comparable loss of branchial motoneurons of the spinal accessory nerve at the C3-C4 level

absent neuronal precursor cells ( J:81765 )

• homozygotes lack most of the migratory neuronal precursor cells that represent branchial motoneuron progenitors of the spinal accessory nerve but contain increased numbers of median motor column neurons

abnormal accessory nerve morphology ( J:81765 )

• at E10.5 and E11.5, homozygotes display significantly reduced length and thickness of the spinal accessory nerve, along with a 60-70% reduction in the number of branchial motoneurons at the C3-C4 level of the spinal cord

abnormal vagus nerve morphology ( J:81765 )

• the axon bundle of the vagal nerve is reduced

fusion of glossopharyngeal and vagus nerve ( J:81765 )

• at E10.5 and E11.5, ~50% of homozygotes display partial fusion of the glossopharyngeal (IXth) and vagal (Xth) nerves

• in contrast, the hypoglossal nerve (XIIth) and cervical motor nerves appear morphologically unchanged with normal ventral axon projections

cellular

abnormal axon guidance ( J:102358 )

• at E11, dorsally directed spinal accessory motor neuron axons reach the lateral exit points but fail to exit the spinal cord at cervical levels; in contrast, normal axon projection and exit is noted at hindbrain levels