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Updated: Jul 9, 2026
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Isolation and Culture of Oculomotor, Trochlear, and Spinal Motor Neurons from Prenatal Islmn:GFP Transgenic Mice
Published on: November 12, 2019
Optic nerve axon number in mouse is regulated by PAX2
Ramakrishna P Alur1, Terry A Cox, Mary Alice Crawford
1Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
Summary
Mutations in the PAX2 gene reduce optic nerve axon number in mice. Tyrosinase does not appear to affect this PAX2-related phenotype, suggesting different developmental pathways.
Area of Science:
- Developmental biology
- Genetics
- Neuroscience
Background:
- Papillorenal syndrome is an autosomal-dominant disorder linked to mutations in the PAX2 transcription factor gene.
- Patients present with congenital optic nerve excavation and kidney abnormalities.
- This study utilizes a novel mouse model (C57BL/6J PAX2(A220G/+)) to investigate PAX2 haploinsufficiency effects.
Purpose of the Study:
- To determine the impact of PAX2 haploinsufficiency on optic nerve axon number in a mouse model.
- To investigate whether tyrosinase (Tyr) modifies the ocular phenotype associated with PAX2 mutations, given their mutually exclusive expression patterns during development.
Main Methods:
- Generation of four distinct mouse genotypes by crossing C57BL/6J PAX2(A220G/+) mice with C57BL/6J Tyr(c-2J/c-2J) mice.
- Clinical and histological examination of mouse optic nerves.
- Masked assessment of optic nerve axon number in all genotypes and comparison with parental strains.
Main Results:
- Mice heterozygous for the PAX2 mutation exhibited a significant reduction in optic nerve axon number compared to age-matched controls.
- Tyrosinase activity did not appear to modify the reduced optic nerve axon number phenotype observed in the PAX2 mutant mice.
Conclusions:
- PAX2 plays a crucial role in regulating optic nerve axon number during development.
- The developmental pathways influenced by tyrosinase and PAX2 mutations appear to be distinct.
