Abstract
Purpose:
Purpose To examine the role of planar cell polarity (PCP) signaling system in mammalian eye development, we carried out gene ablation in a core PCP component, the mammalian homologue of prickle (Pk1).
Methods:
Different Pk1 mutant alleles were generated using conditional knock-in and knockout strategy with Foxg1-Cre and Sox2-Cre driver lines. Retinal function was analyzed using electoretinography (ERG). Retinal histology was examined using immunohistochemistry (IHC), and electron microscopy (EM). Retinal vasculature was visualized with IHC with antibodies and isolectin IB4 that highlight vascular endothelia or pericytes.
Results:
The targeted alleles produced a varying range of PK1 expression levels, from near complete null to severe hypomorphs, and mutant phenotypes correlated with the extent of protein loss. Mutant mice manifest eyelid defect and misorientation of eyelashes. ERG recordings show significant decrease of a- and b-wave amplitudes under both dark- and light-adapted conditions. Lens suture pattern and epithelial cell morphology are altered giving rise to congenital cataract. Photoreceptor outer segments appear disorganized. Staining for RGC markers with anti-Brain3a, anti-NeuN and anti-Neurofilament is attenuated. Retinal vasculature exhibits increased tortuosity and branching defects. Thus, reduced PK1 expression affects all layers of the neural retina, the lens and extraocular tissues.
Conclusions:
PCP signaling is critical for ocular development and function, probably through controlling establishment of correct cell polarity.
Keywords: 539 genetics •
447 cell-cell communication •
698 retinal development