Repository logo
 

Ectodermal Wnt signaling, cell fate determination, and polarity of the skate gill arch skeleton.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Sleight, Victoria A 
Clark, Stephen J 
Nakamura, Tetsuya 

Abstract

The gill skeleton of cartilaginous fishes (sharks, skates, rays, and holocephalans) exhibits a striking anterior-posterior polarity, with a series of fine appendages called branchial rays projecting from the posterior margin of the gill arch cartilages. We previously demonstrated in the skate (Leucoraja erinacea) that branchial rays derive from a posterior domain of pharyngeal arch mesenchyme that is responsive to Sonic hedgehog (Shh) signaling from a distal gill arch epithelial ridge (GAER) signaling centre. However, how branchial ray progenitors are specified exclusively within posterior gill arch mesenchyme is not known. Here, we show that genes encoding several Wnt ligands are expressed in the ectoderm immediately adjacent to the skate GAER, and that these Wnt signals are transduced largely in the anterior arch environment. Using pharmacological manipulation, we show that inhibition of Wnt signalling results in an anterior expansion of Shh signal transduction in developing skate gill arches, and in the formation of ectopic anterior branchial ray cartilages. Our findings demonstrate that ectodermal Wnt signalling contributes to gill arch skeletal polarity in skate by restricting Shh signal transduction and chondrogenesis to the posterior arch environment and highlights the importance of signalling interactions at embryonic tissue boundaries for cell fate determination in vertebrate pharyngeal arches.

Description

Keywords

Shh, Wnt, developmental biology, evolutionary biology, gill arch, pharyngeal arch, skate leucoraja erinacea, skeleton, Animals, Branchial Region, Wnt Signaling Pathway, Hedgehog Proteins, Ectoderm, Gills, Skates, Fish, Skeleton

Journal Title

Elife

Conference Name

Journal ISSN

2050-084X
2050-084X

Volume Title

Publisher

eLife Sciences Publications Ltd
Sponsorship
Royal Society (RG140377)
The Royal Society (uf130182)
Royal Society (URF/R/191007)
Relationships
Is previous version of: