Phenotypes associated with this allele

• Allele Symbol: Isl2⁺
• Allele Name: wild type
• Allele ID: MGI:2434242
• Summary: 4 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
ht1	Isl2^tm3.1(Mnx1-Lhx3)Slp/Isl2^+	Not Specified	MGI:3767808
cn2	Nrg1^tm1Cbm/Nrg1^tm3Cbm Isl2^tm1Arbr/Isl2^+	involves: 129P2/OlaHsd * 129S7/SvEvBrd * C57BL/6J	MGI:3723120
cn3	Mnx1^tm4(cre)Tmj/Mnx1^+ Isl2^tm1Arbr/Isl2^+	involves: 129S7/SvEvBrd * C57BL/6J	MGI:3583819
cx4	Isl2^tm3.1(Mnx1-Lhx3)Slp/Isl2^+ Tg(Mnx1-GFP)1Slp/?	Not Specified	MGI:3767837

Genotype
MGI:3767808

ht1

• Allelic Composition: Isl2^{tm3.1(Mnx1-Lhx3)Slp}/Isl2⁺
• Genetic Background: Not Specified

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

mortality/aging

neonatal lethality, complete penetrance ( J:63774 )

• mice die at birth due to respiratory failure

nervous system

abnormal motor neuron morphology ( J:63774 )

• several markers of motor neurons are absent (Lhx4, Lhx1 and Er81) indicating that motor neurons have adopted a axial-innervating identity (medial half of median motor column)

• at E15.5, no Isl1+ cells in the intermediolateral position of the preganglionic motor column (PGC) motor neurons are detected in the thorax compared to 12+/-2 intermediolateral PGC cells in control mice

• fewer motor neurons project to their target

• lateral motor column (LMC) motor neurons fail to migrate from the ventral spinal cord to their normal intermediolateral position

abnormal motor neuron innervation pattern ( J:63774 )

• axial innervations are increased whereas limb innervations are decreased

abnormal axon morphology ( J:63774 , J:122940 )

• while axons arbourize extensively the ramus visceralis branch is nearly absent (J:63774)

• explants exhibit an increased in the number of axons attracted to the dermomyotome compared with explants from wild-type mice (J:122940)

respiratory system

respiratory failure ( J:63774 )

Genotype
MGI:3723120

cn2

• Allelic Composition: Nrg1^tm1Cbm/Nrg1^tm3Cbm; Isl2^tm1Arbr/Isl2⁺
• Genetic Background: involves: 129P2/OlaHsd * 129S7/SvEvBrd * C57BL/6J

mortality/aging

neonatal lethality, incomplete penetrance ( J:69623 )

• ~90% of mice die at birth, with phenotype similar to Nrg1^tm1Cbm homozygous embryos

nervous system

absent Schwann cells ( J:69623 )

• Schwann cells are absent from intramuscular motor axons between E13.5-E16.5

abnormal nervous system development ( J:69623 )

abnormal motor neuron morphology ( J:69623 )

• motor neurons are defasciculated and disorganized

abnormal motor neuron innervation pattern ( J:69623 )

• in developing muscle, motor axons largely retract by birth; by E18.5, motor axons and terminals are absent

abnormal neuromuscular synapse morphology ( J:69623 )

• at diaphragm synapses, band of acetylcholine receptors (AChRs) is wider (17.5% of muscle length) than in wild-type muscle (7% of muscle length)

cellular

absent Schwann cells ( J:69623 )

• Schwann cells are absent from intramuscular motor axons between E13.5-E16.5

Genotype
MGI:3583819

cn3

• Allelic Composition: Mnx1^tm4(cre)Tmj/Mnx1⁺; Isl2^tm1Arbr/Isl2⁺
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6J

nervous system

abnormal motor neuron morphology ( J:69623 , J:76364 )

• mice lack motor neurons when examined from E12 to E16.9 (J:69623)

Genotype
MGI:3767837

cx4

• Allelic Composition: Isl2^{tm3.1(Mnx1-Lhx3)Slp}/Isl2⁺; Tg(Mnx1-GFP)1Slp/?
• Genetic Background: Not Specified

nervous system

abnormal motor neuron morphology ( J:122940 )

• the increased number of axons attracted to the dermomyotome is due to an increase in GFP+ neurons and not other neuronal types