451. Pax6-dependence of Six3, Eya1 and Dach1 expression during lens and nasal placode induction.
- Author
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Purcell P, Oliver G, Mardon G, Donner AL, and Maas RL
- Subjects
- Animals, Eye Proteins analysis, Eye Proteins genetics, Gene Expression Regulation, Developmental, Homeodomain Proteins analysis, Homeodomain Proteins genetics, Intracellular Signaling Peptides and Proteins analysis, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins metabolism, Lens, Crystalline chemistry, Lens, Crystalline metabolism, Mice, Mice, Knockout, Nasal Mucosa metabolism, Nerve Tissue Proteins analysis, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Nose chemistry, Nuclear Proteins analysis, Nuclear Proteins genetics, Nuclear Proteins metabolism, PAX6 Transcription Factor, Paired Box Transcription Factors analysis, Paired Box Transcription Factors genetics, Protein Tyrosine Phosphatases analysis, Protein Tyrosine Phosphatases genetics, Protein Tyrosine Phosphatases metabolism, Repressor Proteins analysis, Repressor Proteins genetics, Homeobox Protein SIX3, Eye Proteins metabolism, Homeodomain Proteins metabolism, Lens, Crystalline embryology, Nose embryology, Paired Box Transcription Factors metabolism, Repressor Proteins metabolism
- Abstract
The Drosophila eyeless gene plays a central role in fly eye development and controls a subordinate regulatory network consisting of the so, eya and dac genes. All three genes have highly conserved mammalian homologs, suggesting possible conservation of this eye forming regulatory network. sine oculis (so) belongs to the so/Six gene family, and Six3 is prominently expressed in the developing mammalian eye. Eya1 and Dach1 are mammalian homologs of eya and dac, respectively, and although neither Eya1 nor Dach1 knockout mice express prenatal eye defects, possibilities exist for postnatal ocular phenotypes or for functional redundancy between related family members. To examine whether expression relationships analogous to those between ey, so, eya and dac exist in early mammalian oculogenesis, we investigated Pax6, Six3, Eya1 and Dach1 protein expression in murine lens and nasal placode development. Six3 expression in the pre-placode lens ectoderm is initially Pax6-independent, but subsequently both its expression and nuclear localization become Pax6-dependent. Six3, Dach1 and Eya1 nasal expression in pre-placode ectoderm are also initially Pax6-independent, but thereafter become Pax6-dependent. Pax6, Six3, Dach1 and Eya1 are all co-expressed in the developing ciliary marginal zone, a source of retinal stem cells in some vertebrates. An in vitro protein-protein interaction is detected between Six3 and Eya1. Collectively, these findings suggest that the Pax-Eya-Six-Dach network is at best only partly conserved during lens and nasal placode development. However, the findings do not rule out the possibility that such a regulatory network acts at later stages of oculogenesis.
- Published
- 2005
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