Deployment of a retinal determination gene network drives directed cell migration in the sea urchin embryo.

Megan L Martik,David R Mcclay

doi:10.7554/elife.08827

Abstract

Gene regulatory networks (GRNs) provide a systems-level orchestration of an organism's genome encoded anatomy. As biological networks are revealed, they continue to answer many questions including knowledge of how GRNs control morphogenetic movements and how GRNs evolve. The migration of the small micromeres to the coelomic pouches in the sea urchin embryo provides an exceptional model for understanding the genomic regulatory control of morphogenesis. An assay using the robust homing potential of these cells reveals a 'coherent feed-forward' transcriptional subcircuit composed of Pax6, Six3, Six1/2, Eya, and Dach1 that is responsible for the directed homing mechanism of these multipotent progenitors. The linkages of that circuit are strikingly similar to a circuit involved in retinal specification in Drosophila suggesting that systems-level tasks can be highly conserved even though the tasks drive unrelated processes in different animals.

Highlights

Much research has been done to understand the cell biology underlying the events of directed cell migration; how the events are encoded in the genome and how gene regulatory networks (GRNs) control this process are works in progress
Underlying GRNs specify each of the coelomic pouch cell types and the small micromeres early in development (Oliveri et al, 2006; Peter and Davidson, 2011; Materna et al, 2012)
Given the ability to experimentally move the small micromeres to ectopic locations, we first learned that the small micromeres had a remarkable ability to home to the coelomic pouches

Summary

Introduction

Much research has been done to understand the cell biology underlying the events of directed cell migration; how the events are encoded in the genome and how gene regulatory networks (GRNs) control this process are works in progress. A near complete developmental GRN describes the specification of endomesoderm (McClay, 2011; Peter and Davidson, 2011). Studies of this specification network have made the sea urchin a viable model for extending the study of how GRNs can explain control of complex cell behaviors (Saunders and McClay, 2014).

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