Molecular description of eye defects in the zebrafish Pax6b mutant, sunrise, reveals a Pax6b-dependent genetic network in the developing anterior chamber

Masanari Takamiya; Benjamin D Weger; Simone Schindler; Tanja Beil; Lixin Yang; Olivier Armant; Marco Ferg; Günther Schlunck; Thomas Reinhard; Thomas Dickmeis; Sepand Rastegar; Uwe Strähle

doi:10.1371/journal.pone.0117645

Molecular description of eye defects in the zebrafish Pax6b mutant, sunrise, reveals a Pax6b-dependent genetic network in the developing anterior chamber

PLoS One. 2015 Feb 18;10(2):e0117645. doi: 10.1371/journal.pone.0117645. eCollection 2015.

Affiliations

¹ Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe, Germany.
² Eye Center, Freiburg University Medical Center, Killianstr. 5, 79106 Freiburg, Germany.

Abstract

The cornea is a central component of the camera eye of vertebrates and even slight corneal disturbances severely affect vision. The transcription factor PAX6 is required for normal eye development, namely the proper separation of the lens from the developing cornea and the formation of the iris and anterior chamber. Human PAX6 mutations are associated with severe ocular disorders such as aniridia, Peters anomaly and chronic limbal stem cell insufficiency. To develop the zebrafish as a model for corneal disease, we first performed transcriptome and in situ expression analysis to identify marker genes to characterise the cornea in normal and pathological conditions. We show that, at 7 days post fertilisation (dpf), the zebrafish cornea expresses the majority of marker genes (67/84 tested genes) found also expressed in the cornea of juvenile and adult stages. We also characterised homozygous pax6b mutants. Mutant embryos have a thick cornea, iris hypoplasia, a shallow anterior chamber and a small lens. Ultrastructure analysis revealed a disrupted corneal endothelium. pax6b mutants show loss of corneal epithelial gene expression including regulatory genes (sox3, tfap2a, foxc1a and pitx2). In contrast, several genes (pitx2, ctnnb2, dcn and fabp7a) were ectopically expressed in the malformed corneal endothelium. Lack of pax6b function leads to severe disturbance of the corneal gene regulatory programme.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Anterior Chamber / growth & development*
Anterior Chamber / metabolism*
Anterior Chamber / pathology
Endothelium, Corneal / growth & development
Endothelium, Corneal / metabolism
Endothelium, Corneal / pathology
Eye Proteins / genetics*
Eye Proteins / metabolism
Gene Expression Profiling
Gene Expression Regulation, Developmental
Gene Regulatory Networks*
Homeodomain Proteins / genetics*
Homeodomain Proteins / metabolism
Larva / genetics
Larva / growth & development
Mutation*
PAX6 Transcription Factor
Paired Box Transcription Factors / genetics*
Paired Box Transcription Factors / metabolism
Repressor Proteins / genetics*
Repressor Proteins / metabolism
Retina / growth & development
Retina / metabolism
Retina / pathology
Zebrafish / genetics*
Zebrafish / growth & development*

Substances

Eye Proteins
Homeodomain Proteins
PAX6 Transcription Factor
PAX6 protein, human
Paired Box Transcription Factors
Repressor Proteins

Grants and funding

US was funded by the Helmholtz Association; the European commission integrating project ZF-MODELS “Zebrafish Models for Human Development and Disease” (6th Framework Programme), LSHG-CT-2003-503496; the European commission EUTRACC “European Transcriptome Regulome & Cellular Commitment Consortium” LSHG-CT-2006-037445; and the European commission integrating project ZF-HEALTH “Zebrafish Regulomics for Human Health” (7th Framework Programme), FP7-HEALTH-2009-2-STAGE. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.