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Phenotypes Associated with This Genotype
Genotype
MGI:3843807
Allelic
Composition
Erbb2tm1Haus/Erbb2tm1Klee
Myf5tm3(cre)Sor/Myf5+
Genetic
Background
involves: 129S4/SvJae * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Erbb2tm1Haus mutation (0 available); any Erbb2 mutation (59 available)
Erbb2tm1Klee mutation (0 available); any Erbb2 mutation (59 available)
Myf5tm3(cre)Sor mutation (1 available); any Myf5 mutation (17 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• mice show a flexed posture when inverted
• mice exhibit a wide-based, ataxic gait

nervous system
• only rudimentary muscle spindles with a single Egr3-positive myofiber are seen in tibialis anterior muscles at P3 in contrast to spindles in controls which have multiple Egr3+ intrafusal myofibers
• on P4 muscle spindles, few mutant spindles have the complex annulospiral afferent terminal seen around the equatorial region of intrafusal myofibers in control muscle; muscle spindle afferent terminal morphology is simple compared to controls
• spindle development fails to progress beyond E18 and mature spindles do not form
• in tibialis anterior (TA) muscle, muscle spindle numbers are decreased 70% from those of controls
• innervation of muscle spindles is simpler than observed in controls, but spindle afferent projection to the ventral spinal cord shows normal pattern
• monosynaptic inputs from muscle spindle afferent to motor neurons are functional but reduced in amplitude; EPSPs evoked by dorsal root stimulation or evoked by muscle nerve stimulation are reduced from those of controls by similar amounts (to about 22-26% of wild-type amplitudes)

muscle
• only rudimentary muscle spindles with a single Egr3-positive myofiber are seen in tibialis anterior muscles at P3 in contrast to spindles in controls which have multiple Egr3+ intrafusal myofibers
• on P4 muscle spindles, few mutant spindles have the complex annulospiral afferent terminal seen around the equatorial region of intrafusal myofibers in control muscle; muscle spindle afferent terminal morphology is simple compared to controls
• spindle development fails to progress beyond E18 and mature spindles do not form
• in tibialis anterior (TA) muscle, muscle spindle numbers are decreased 70% from those of controls


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
03/25/2025
MGI 6.24
The Jackson Laboratory