# An Integrated Canonical and Non-Canonical Wnt Signaling Network Controls Early Anterior–Posterior Axis Formation in Sea Urchin Embryos

## TL;DR

This paper explores how Wnt signaling pathways work together to form the front-to-back body axis in sea urchin embryos, offering insights into a conserved developmental process across animals.

## Contribution

The study reveals an interconnected network of three Wnt pathways in sea urchin embryos that controls early anterior-posterior axis formation.

## Key findings

- Three Wnt signaling pathways (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC) form an interconnected network in sea urchin embryos.
- The Wnt signaling network specifies and patterns the anterior-posterior axis during early development.
- Aspects of the sea urchin Wnt network are conserved across a wide range of metazoans.

## Abstract

Wnt signaling is an ancient developmental mechanism that drives the initial specification and patterning of the primary axis in many metazoan embryos. Yet, it is unclear how exactly the various Wnt components interact in most Wnt-mediated developmental processes as well as in the molecular mechanism regulating adult tissue homeostasis. Recent work in invertebrate deuterostome sea urchin embryos indicates that three different Wnt signaling pathways (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC) form an interconnected Wnt signaling network that specifies and patterns the primary anterior–posterior (AP) axis. Here, we detail our current knowledge of this critical regulatory process in sea urchin embryos. We also illustrate examples from a diverse group of metazoans, from cnidarians to vertebrates, that suggest aspects of the sea urchin AP Wnt signaling network are deeply conserved. We explore how the sea urchin is an excellent model to elucidate a detailed molecular understanding of AP axis specification and patterning that can be used for identifying unifying developmental principles across animals.