Phenotypes associated with this allele

• Allele Symbol: Nrg1^tm1Leth
• Allele Name: targeted mutation 1, Lars E Theill
• Allele ID: MGI:1928491
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Nrg1^tm1Leth/Nrg1^tm1Leth	involves: 129S1/Sv * C57BL/6	MGI:2175169
hm2	Nrg1^tm1Leth/Nrg1^tm1Leth	Not Specified	MGI:2173314
ht3	Nrg1^tm1Leth/Nrg1^+	involves: 129S1/Sv * C57BL/6	MGI:3530661

Genotype
MGI:2175169

hm1

• Allelic Composition: Nrg1^tm1Leth/Nrg1^tm1Leth
• Genetic Background: involves: 129S1/Sv * C57BL/6

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

mortality/aging

embryonic lethality during organogenesis, complete penetrance ( J:33038 )

• under resorption at E11.5

cardiovascular system

trabecula carnea hypoplasia ( J:33038 )

• severly impaired formation; lack of intertrabecular sinusiods was noted

abnormal atrioventricular cushion morphology ( J:33038 )

• less contracted appearance in mutant embryos

dilated heart ventricle ( J:33038 )

• dilated common ventricle at E10.5 before septation occurs

decreased cardiac output ( J:33038 )

• decreased emptying of the common ventricle was observed at E10.5

decreased cardiac muscle contractility ( J:33038 )

• depressed contractility was observed

decreased heart rate ( J:33038 )

• occasionally displayed

embryo

embryonic growth arrest ( J:33038 )

• arrested at E11.5

muscle

trabecula carnea hypoplasia ( J:33038 )

• severly impaired formation; lack of intertrabecular sinusiods was noted

decreased cardiac muscle contractility ( J:33038 )

• depressed contractility was observed

nervous system

abnormal cranial ganglia morphology ( J:33038 )

• the proximal part of the facio-acoustic ganglion complex is abnormal; mean area reduced by 30%

• the petrosal and nodose ganglia appear normal

• affected ganglia appear to have cells that originated in the crainal neural crest and unaffected ganglia appear to have cells that originated in the placode

abnormal trigeminal ganglion morphology ( J:33038 )

• the proximal region including the mandibular branch and CNS projection is missing

• total area of the ganglion is reduced by 66%

• disruption of cellular organization, vacuolization and karyorrhexis was seen

abnormal glossopharyngeal nerve morphology ( J:33038 )

• compromised projections to the brain stem

abnormal mandibular nerve branching ( J:33038 )

abnormal vagus nerve morphology ( J:33038 )

• compromised projections to the brain stem

Genotype
MGI:2173314

hm2

• Allelic Composition: Nrg1^tm1Leth/Nrg1^tm1Leth
• Genetic Background: Not Specified

nervous system

nervous system phenotype ( J:43309 )

N • normal appearance and numbers of Schwann cells

Genotype
MGI:3530661

ht3

• Allelic Composition: Nrg1^tm1Leth/Nrg1⁺
• Genetic Background: involves: 129S1/Sv * C57BL/6

nervous system

abnormal neuromuscular synapse morphology ( J:39800 )

• a 51% reduction in the density of acetylcholine receptors on the postsynaptic membrane was observed by [125-I] bungarotoxin staining

• no increase in size of the endplate was observed

abnormal PNS synaptic transmission ( J:39800 )

• neuromuscular synapse transmission was more sensitive to curare in heterozygotes than controls

• repetitive nerve stimulation stimulated compound muscle action potentials in heterozygous mice similar to controls, but lower doses of curare were required to decrease the amplitude compared to controls

abnormal endplate potential ( J:39800 )

• the mean evoked end plate potenital was not reduced in heterozygotes, although quantal size is reduced; compensatory mechanisms appear to increase the number of quanta released per pulse

• evoked end plate potentials decay more rapidly at heterozygous endplates than at controls

abnormal miniature endplate potential ( J:39800 )

• the mean spontaneous miniature endplate potentials were reduced by approximately 30% in heterozygous mice