Pax6 heterozygous eyes show defects in chamber angle differentiation that are associated with a wide spectrum of other anterior eye segment abnormalities

Daniela C. Baulmann, Andreas Ohlmann, Cassandra Flügel-Koch, Sumanta Goswami, Ales Cvekl, Ernst R. Tamm

Research output: Contribution to journalArticle

118 Scopus citations

Abstract

The development of the chamber angle was studied in the eyes of heterozygous Pax6lacZ/+ mutant mice (Nature 387 (1997) 406). Mutations in PAX6 cause aniridia, a condition that is frequently associated with glaucoma, a blinding disease that may be associated with chamber angle defects. Mesenchymal cells were seen in the chamber angle at P1-P5. In wild-type mice, these cells differentiated into typical trabecular meshwork (TM) cells next to Schlemm's canal. In Pax6lacZ/+ mice, TM cells remained undifferentiated and Schlemm's canal was absent. From P1 to P4, staining for β-galactosidase and immunoreactivity for Pax6 were observed in chamber angle mesenchyme, but were absent later. Cultured murine TM cells expressed Pax6. The defects in chamber angle and TM differentiation were associated with a wide spectrum of other anterior eye defects, which included various degrees of iris hypoplasia and corneal haze, isolated iridocorneal adhesions and atypical coloboma, and a vascularized cornea in all adult animals. A third of the animals showed Peters' anomaly including corneal opacity and iridocorneal adhesions. The separation of the lens from the cornea was incomplete, and epithelial layers of lens and cornea were continuous. Pax6 activity is directly required for differentiation of the chamber angle. Variations in phenotype of Pax6lacZ/+ mice appear not to involve direct dominant-negative or dose-dependent effects.

Original languageEnglish (US)
Pages (from-to)3-17
Number of pages15
JournalMechanisms of Development
Volume118
Issue number1-2
DOIs
StatePublished - Oct 1 2002

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Keywords

  • Cornea
  • Iris
  • Pax6
  • Peters' anomaly
  • Schlemm's canal
  • Trabecular meshwork

ASJC Scopus subject areas

  • Embryology
  • Developmental Biology

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