The zebrafish Pard3 ortholog is required for separation of the eye fields and retinal lamination

Abstract

The vertebrate retina develops from a sheet of neuroepithelial cells. Because adherens and tight junctions are critical for epithelial and neuronal differentiation in a variety of eukaryotic systems, we examined the role of Par-3, a PDZ scaffold protein that is critical in cellular membrane junction formation. We cloned the zebrafish Par-3 ortholog (pard3), which encodes two Pard3 proteins (150 and 180 kDa) that differ in their carboxyl-terminus. Immunohistochemistry revealed that Pard3 localized to the apical region of the retinal and brain neuroepithelium, partially overlapping the adherens junction-associated actin bundles. After retinal lamination, the Pard3 protein was restricted to the outer limiting membrane and the outer and inner plexiform layers in the retina. Reducing Pard3 expression with antisense morpholinos caused loss of the retinal pigmented epithelia, disruption of retinal lamination, and cell death in the ventral diencephalon, which resulted in cyclopia. Overexpressing Pard3 by injection of wild-type pard3 mRNA resulted in cyclopia and eyeless embryos. Thus, Pard3 plays a critical role in the origination and separation of zebrafish eye fields and retinal lamination.

Atp6ap2/(Pro)renin Receptor Interacts with Par3 as a Cell Polarity Determinant Required for Laminar Formation during Retinal Development in Mice

“…Electroretinography (ERG) recordings were performed as described previously (Yuki et al, 2011). In brief, male mice at the age of 4 weeks were dark-adapted overnight, and then anesthetized with an intramuscular injection of 70 mg/kg pentobarbital sodium and the pupils were dilated with a mixed solution of 0.5% tropicamide and 0.5% phenylephrine (Mydrin-P, Santen) just before light exposure.…”

“…The partitioning defective 3 homolog (Par3)-Par6-atypical protein kinase C (aPKC) complex (i.e., the Par-aPKC system) interacts with adherens junctions for the establishment and maintenance of cell polarity during retinal development. Genetic ablation of each of those adhesion and polarity molecules has been reported to result in severe disorganization of the retinal architecture (Horne-Badovinac et al, 2001;Wei and Malicki, 2002;Malicki et al, 2003;Masai et al, 2003;Wei et al, 2004;Koike et al, 2005).…”

Zebrafish: A model system for the study of eye genetics

“…In the mutant embryos, mitotic activity was not restricted to the apical margin but rather was distributed across the width of the neuroepithelium. Subsequent cloning revealed that several of the mutations disrupted genes involved in epithelial junctional complexes, demonstrating the importance of maintaining epithelial polarity for the appropriate radial arrangement of neuroprogenitors and lamination of the retina (Jensen and Westerfield, 2004;Malicki, et al, 2003;Wei and Malicki, 2002;Wei et al, 2004).…”

Lengsin expression and function during zebrafish lens formation

“…A control morpholino (mmC) with 5 mismatches relative to the MorfA sequence was also used: 5′-GGATTgCTCTcATTgTTcCATcATG-3′. The morpholinos were resuspended in nuclease-free water (0.5 mM) and approximately 5 nL (~7 ng) was microinjected into 1-4 cell-stage embryos as previously described (Wei et al, 2004;Shi et al, 2005;Shi et al, 2006). The control and morpholino-injected embryos were raised at 28.5°C and were screened at 24 hpf to remove unfertilized eggs and those embryos exhibiting developmental delays due to morpholino toxicity or non-specific effects.…”