Evolution of intercellular patterning mechanisms


Evolution of intercellular patterning mechanisms in deuterostomes: differential deployment of Wnt and retinoic acid signaling in sea urchin, amphioxus and lamprey development

The aim of this project is to complement the two other projects by studying the molecular interactions between retinoic acid (RA) and Wnt signaling in sea urchins, amphioxus and lampreys (Fig. 1) in relation to their biological functions during development, e.g. in embryonic axis establishment and tissue specification (Fig. 2).
Using classical microinjection- and pharmacology-based embryological experiments combined with comprehensive transcriptomic surveys, we are aiming to provide a detailed description of tissue-specific interactions of RA and Wnt signaling in our three animal models (Fig. 1). Preliminary analyses indicate, for example, that in sea urchins and amphioxus, endoderm formation relies on both Wnt and RA signaling for proper specification and anteroposterior regionalization, respectively. However, potential regulatory interactions between these two cascades in the endoderm remain to be determined, as do their functions in lampreys.
In addition, in both amphioxus and lampreys, RA signaling is required not only for regionalization of the central nervous system, but also for neuronal specification and neurogenesis. Given that these processes likely also depend on Wnt signals, the question of functional interactions between the two cascades arises. Altogether, this work will shed light on the evolution of functional interactions of these two fundamental intercellular signaling pathways in deuterostomes.


Figure 1. Simplified phylogeny of metazoan animals (modified from Campo-Paysaa et al., 2008, Genesis, 46:640-656).



Figure 2. Potential interactions of retinoic acid (RA) and Wnt signaling in deuterostomes development.

Michael Schubert - 25/09/17