Phenotypes associated with this allele

• Allele Symbol: Egr3^tm1Jmi
• Allele Name: targeted mutation 1, Jeffrey Milbrandt
• Allele ID: MGI:2180063
• Summary: 6 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Egr3^tm1Jmi/Egr3^tm1Jmi	involves: C57BL/6	MGI:5489936
hm2	Egr3^tm1Jmi/Egr3^tm1Jmi	Not Specified	MGI:3688874
cn3	Egr3^tm1Jmi/Egr3^tm2.1Wgt Tg(DBH-cre,-taulacZ)1Wgt/0	involves: 129P2/OlaHsd * C57BL/6 * SJL	MGI:5489937
cn4	Egr3^tm1Jmi/Egr3^tm1Jmi Gt(ROSA)26Sor^tm1(CAG-taulacZ)Bene/Gt(ROSA)26Sor^+ Tg(Dbh-cre)KH212Gsat/0	involves: C57BL/6 * FVB/NTac	MGI:5489938
cx5	Egr3^tm1Jmi/Egr3^tm1Jmi Gfra1^tm3Jmi/Gfra1^+	involves: 129X1/SvJ	MGI:4456173
cx6	Egr3^tm1Jmi/Egr3^tm1Jmi Gfra1^tm3Jmi/Gfra1^+ Tg(Hlxb9-GFP)1Tmj/0	involves: 129X1/SvJ * C57BL/6 * SJL	MGI:4456172

Genotype
MGI:5489936

hm1

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm1Jmi
• Genetic Background: involves: C57BL/6

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

behavior/neurological

abnormal gait ( J:243559 )

• impaired gait that is less severe than in Runx3 null mice

skeleton

scoliosis ( J:243559 )

• develops between P40 and P90

• severity is reduced compared to Runx3 mice

nervous system

abnormal sympathetic neuron morphology ( J:196371 )

• superior cervical ganglion neurons grown in dissociated culture treated with NGF have fewer neurite branch points, decreased total neurite length and a reduction in length of the longest neurite compared to cultured wild-type neurons

Genotype
MGI:3688874

hm2

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm1Jmi
• Genetic Background: Not Specified

mortality/aging

postnatal lethality, incomplete penetrance ( J:49575 )

• born in expected numbers but 40% are dead by weaning

nervous system

abnormal cholinergic neuron morphology ( J:160727 )

• at birth, mice exhibit a modest loss of all sizes of cholinergic motor neurons compared with wild-type mice

• at P5, mice exhibit increased motor neuron loss compared with wild-type mice due to loss of small diameter gamma-motor neurons

• at P10, loss of gamma-motor neurons is more complete with a 25% loss of gamma-motor neurons compared with wild-type mice

• at P20, mice exhibit a loss of small diameter cholinergic motor neurons compared with wild-type mice

decreased motor neuron number ( J:160727 )

• at birth, mice exhibit a modest loss of all sizes of cholinergic motor neurons compared with wild-type mice

• at P5, mice exhibit increased motor neuron loss compared with wild-type mice due to loss of small diameter gamma-motor neurons

• at P10, loss of gamma-motor neurons is more complete with a 25% loss of gamma-motor neurons compared with wild-type mice

• at P20, mice exhibit a loss of small diameter cholinergic motor neurons compared with wild-type mice

abnormal somatic sensory system morphology ( J:49575 )

abnormal muscle spindle morphology ( J:76256 )

• number of muscle spindles is normal at birth but progressively disassemble

• only about 1/3 of normal numbers are present at 12 days of age and those are about 50% smaller than normal

• spindle response to stimulation is defective

absent muscle spindles ( J:49575 )

• adult skeletal muscles lack muscle spindles

• normal numbers of type I extrafusal fibers

abnormal dorsal root ganglion morphology ( J:49575 )

• 75% loss of large myelinated fibers and 90% loss of small myelinated fibers from the L4 dorsal root ganglion

abnormal proprioceptive neuron morphology ( J:49575 , J:76256 )

• normal numbers of proprioceptive neurons in newborn mice but the neurons are smaller in size (J:49575)

• numbers of myelinated neurons drops to 75% of control numbers in adults (J:76256)

• neuron loss is primarily type Ia and II sensory as well as gamma motor neurons (J:76256)

• type Ib sensory neurons are unaffected (J:76256)

abnormal nervous system physiology ( J:76256 )

abnormal somatic nervous system physiology ( J:76256 )

• type Ia neurons function normally during first week of life but synaptic connection to motoneurons is lost at 2 days of age

abnormal excitatory postsynaptic potential ( J:76256 )

• loss of monosynaptic excitatory postsynaptic potential normally generated by stimulation of proprioceptive neurons of muscles

behavior/neurological

tremors ( J:49575 )

• prominent resting tremors

ataxia ( J:49575 )

abnormal limb posture ( J:49575 )

• abnormal limb position when stationary

abnormal gait ( J:49575 )

• waddling, uncoordinated gait

muscle

abnormal muscle spindle morphology ( J:76256 )

• number of muscle spindles is normal at birth but progressively disassemble

• only about 1/3 of normal numbers are present at 12 days of age and those are about 50% smaller than normal

• spindle response to stimulation is defective

absent muscle spindles ( J:49575 )

• adult skeletal muscles lack muscle spindles

• normal numbers of type I extrafusal fibers

vision/eye

blepharoptosis ( J:49575 )

skeleton

scoliosis ( J:49575 )

Genotype
MGI:5489937

cn3

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm2.1Wgt; Tg(DBH-cre,-taulacZ)1Wgt/0
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6 * SJL

nervous system

superior cervical ganglion degeneration ( J:196371 )

• conditional mutants display neuron loss in the superior cervical ganglion (SCG), similar to that described in germline Egr3 mutants

abnormal sympathetic neuron innervation pattern ( J:196371 )

• peripheral sympathetic target tissue innervation is abnormal in conditional mutants, closely resembling defects described in germline Egr3 mutants; innervation to the heart, spleen, kidney, and pineal gland is reduced

vision/eye

blepharoptosis ( J:196371 )

• sympathetic nervous system abnormalities like blepharoptosis are evident in conditional mutants, similar to defects described in germline Egr3 mutants

behavior/neurological

behavior/neurological phenotype ( J:196371 )

N • mice lack the scoliosis and gait ataxia observed in Egr3 germline mutants

Genotype
MGI:5489938

cn4

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm1Jmi; Gt(ROSA)26Sor^{tm1(CAG-taulacZ)Bene}/Gt(ROSA)26Sor⁺; Tg(Dbh-cre)KH212Gsat/0
• Genetic Background: involves: C57BL/6 * FVB/NTac

nervous system

nervous system phenotype ( J:196371 )

N • no significant differences are detected in sympathetic axon guidance; axon guidance to the submandibular gland is similar in mutants and controls

abnormal sympathetic neuron morphology ( J:196371 )

• (lacZ-labeled) mutant neurons have fewer primary dendrites compared to controls in the superior cervical ganglion (SCG) and stellate ganglion; labeled neurons have decreased total dendrite length and decrease in maximum extent of the dendritic arbor in the SCG

• neurons are significantly atrophic compared with control (decreased mean soma area)

Genotype
MGI:4456173

cx5

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm1Jmi; Gfra1^tm3Jmi/Gfra1⁺
• Genetic Background: involves: 129X1/SvJ

nervous system

abnormal cholinergic neuron morphology ( J:160727 )

• mice exhibit selective loss of small cholinergic neurons unlike wild-type mice

• total numbers of cholinergic neurons in the L4-5 section of the spinal cord is decreased compared to in wild-type mice

decreased motor neuron number ( J:160727 )

• total numbers of cholinergic neurons in the L4-5 section of the spinal cord is decreased compared to in wild-type mice

Genotype
MGI:4456172

cx6

• Allelic Composition: Egr3^tm1Jmi/Egr3^tm1Jmi; Gfra1^tm3Jmi/Gfra1⁺; Tg(Hlxb9-GFP)1Tmj/0
• Genetic Background: involves: 129X1/SvJ * C57BL/6 * SJL

nervous system

abnormal cholinergic neuron morphology ( J:160727 )

• mice exhibit a loss of small diameter cholinergic motor neurons compared with wild-type mice

abnormal motor neuron morphology ( J:160727 )

• surviving Gfra1+ motor neurons exhibit somatic shrinkage and morphological evidence of degeneration unlike in wild-type mice

decreased motor neuron number ( J:160727 )

• Gfra1+, cholinergic, Gfa1+ HB9-GFP-, and Gfra1+ HB9-GFP+ motor neurons are reduced compared to in wild-type mice

• mice exhibit a loss of small diameter cholinergic motor neurons compared with wild-type mice

• however, the number of large diameter motor neurons is normal

motor neuron degeneration ( J:160727 )

• surviving Gfra1+ motor neurons exhibit somatic shrinkage and morphological evidence of degeneration unlike in wild-type mice