Phenotypes associated with this allele

• Allele Symbol: Chn1^tm1.2Ece
• Allele Name: targeted mutation 1.2, Elizabeth C Engle
• Allele ID: MGI:6406376
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
cx1	Chn1^tm1.2Ece/Chn1^tm1.2Ece Tg(Hlxb9-GFP)1Tmj/0	involves: 129S1/Sv * 129S6/SvEvTac * C57BL/6J	MGI:6406400
cx2	Chn1^tm1.2Ece/Chn1^tm1.2Ece Epha4^tm1.2Bzh/Epha4^tm1.2Bzh Tg(Hlxb9-GFP)1Tmj/0	involves: 129S/Sv * C57BL/6J * CD-1 * FVB/N	MGI:6406415
cx3	Chn1^tm1.2Ece/Chn1^+ Epha4^tm1.2Bzh/Epha4^tm1.2Bzh Tg(Hlxb9-GFP)1Tmj/0	involves: 129S/Sv * C57BL/6J * CD-1 * FVB/N	MGI:6406417

Genotype
MGI:6406400

cx1

• Allelic Composition: Chn1^tm1.2Ece/Chn1^tm1.2Ece; Tg(Hlxb9-GFP)1Tmj/0
• Genetic Background: involves: 129S1/Sv * 129S6/SvEvTac * C57BL/6J

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

nervous system

abnormal innervation ( J:243785 )

• abducens nerve exits with an increased number of defasciculated bundles within the hindbrain, some of which wander dorsally toward the hindbrain or ventrally to track along the developing buccal branch of the facial nerve

• however, a subset of abducens nerve bundles successfully fasciculate within the midway between the hindbrain and orbit and innervate the extraocular muscle anlage at the orbit

• trochlear nerve and first spine projections are unaffected

abnormal abducens nerve morphology ( J:243785 )

• abducens nerve diameter is greater

• however, abducens nerve length is normal

vision/eye

vision/eye phenotype ( J:243785 )

N • mice do not exhibit globe retraction and do not have Duane retraction syndrome

Genotype
MGI:6406415

cx2

• Allelic Composition: Chn1^tm1.2Ece/Chn1^tm1.2Ece; Epha4^tm1.2Bzh/Epha4^tm1.2Bzh; Tg(Hlxb9-GFP)1Tmj/0
• Genetic Background: involves: 129S/Sv * C57BL/6J * CD-1 * FVB/N

nervous system

abnormal innervation ( J:243785 )

• 2 of 5 embryos show orbital innervation failure by abducens nerve

• abducens nerve shows enhanced wandering of abducens bundles

• however, embryos show normalized abducens exit and fasciculation

• embryos show increased abducens nerve stalling compared to homozygous Chn1^tm1.1Ece homozygotes and similar abducens nerve wandering compared to Epha4^tm1.2Bzh homozygotes

• stalled projections do not stay within normal nerve boundaries and instead wander to track with the mandibular and cervical branches of the facial nerve

• the abducens nerve fails to innervate the lateral rectus at E16.5, which instead is innervated by aberrant branches of the oculomotor nerve; this phenotype is worse than seen in single Epha4^tm1.2Bzh homozygotes

abnormal abducens nerve morphology ( J:243785 )

• embryos show a reduction in abducens nerve length and diameter at the orbit

Genotype
MGI:6406417

cx3

• Allelic Composition: Chn1^tm1.2Ece/Chn1⁺; Epha4^tm1.2Bzh/Epha4^tm1.2Bzh; Tg(Hlxb9-GFP)1Tmj/0
• Genetic Background: involves: 129S/Sv * C57BL/6J * CD-1 * FVB/N

nervous system

abnormal innervation ( J:243785 )

• while embryos show normalized abducens exit and fasciculation, abducens nerve stalling is increased in the abducens fasciculation region, with both reduced abducens nerve length and thinner nerve diameter near the orbit

• stalled projections do not stay within normal nerve boundaries and instead wander to track with the mandibular and cervical branches of the facial nerve

abnormal abducens nerve morphology ( J:243785 )

• abducens nerve length is reduced in embryos and nerve diameter is thinner near the orbit