Murine Dishevelled 3 Functions in Redundant Pathways with Dishevelled 1 and 2 in Normal Cardiac Outflow Tract, Cochlea, and Neural Tube Development

S Leah Etheridge,Saugata Ray,Daniel J Sussman,Shuangding Li,Anthony Wynshaw-Boris,Joy Greer,Ping Chen,Jianbo Wang,Nardos Lijam,Natalie Kardos,Natasha S Hamblet,Michael Tsang

doi:10.1371/journal.pgen.1000259

Abstract

Dishevelled (Dvl) proteins are important signaling components of both the canonical β-catenin/Wnt pathway, which controls cell proliferation and patterning, and the planar cell polarity (PCP) pathway, which coordinates cell polarity within a sheet of cells and also directs convergent extension cell (CE) movements that produce narrowing and elongation of the tissue. Three mammalian Dvl genes have been identified and the developmental roles of Dvl1 and Dvl2 were previously determined. Here, we identify the functions of Dvl3 in development and provide evidence of functional redundancy among the three murine Dvls. Dvl3 −/− mice died perinatally with cardiac outflow tract abnormalities, including double outlet right ventricle and persistent truncus arteriosis. These mutants also displayed a misorientated stereocilia in the organ of Corti, a phenotype that was enhanced with the additional loss of a single allele of the PCP component Vangl2/Ltap (LtapLp/+). Although neurulation appeared normal in both Dvl3 −/− and LtapLp/+ mutants, Dvl3 +/−;LtapLp/+ combined mutants displayed incomplete neural tube closure. Importantly, we show that many of the roles of Dvl3 are also shared by Dvl1 and Dvl2. More severe phenotypes were observed in Dvl3 mutants with the deficiency of another Dvl, and increasing Dvl dosage genetically with Dvl transgenes demonstrated the ability of Dvls to compensate for each other to enable normal development. Interestingly, global canonical Wnt signaling appeared largely unaffected in the double Dvl mutants, suggesting that low Dvl levels are sufficient for functional canonical Wnt signals. In summary, we demonstrate that Dvl3 is required for cardiac outflow tract development and describe its importance in the PCP pathway during neurulation and cochlea development. Finally, we establish several developmental processes in which the three Dvls are functionally redundant.

Highlights

Normal mammalian development is the result of complex signaling networks that regulate and coordinate cell behavior
Conotruncal Defects in Dvl32/2 Mice Are Not Due to an Absence of cardiac neural crest (CNC) or secondary heart field (SHF) Cells Normal development of the outflow tract requires contribution from both the CNC and SHF, so we examined whether a lack of either of these tissues in Dvl32/2 mutants may be responsible for the observed conotruncal defects by lineage tracing experiments using lineage-specific Cre/LoxP recombination and a Rosa-26-lacZ Cre reporter that expresses b-galactosidase only in cells with Cre activity
A large body of evidence demonstrates that Dvl proteins function in highly conserved pathways in both vertebrates and invertebrates

Summary

Introduction

Normal mammalian development is the result of complex signaling networks that regulate and coordinate cell behavior. A non-canonical Wnt planar cell polarity (PCP) pathway, parallel to that first discovered in flies, has been described in mammals, where it regulates cell polarity and convergent extension (CE) movements In these coordinated cell movements, cells migrate medially and intercalate, producing an elongation and narrowing of the tissue along the anterior-posterior axis [3,4,5,6,7]. Dishevelled (Dvl) proteins, of which three have been identified in humans and mice [8,9,10,11,12,13] are highly conserved components of both the canonical Wnt and PCP signaling cascades.

Methods

Results

Conclusion