Designing the Bodyplan: Developmental Mechanisms
A workshop sponsored by:
The Lorentz Center, University of Leiden
EU Network of excellence “Cells Into Organs”
The extent to which functional developmental modules are conserved in evolution and re-used repeatedly in embryonic development has been a revelation. These define “Developmental Mechanisms” which implement the embryo's body plan. We discuss and evaluate key aspects in the context of making the embryo’s main body axis. Some aspects are:
a/ Concentration gradients. A key mechanism is that cells respond to quantitatively different concentration ranges in a concentration gradient of an extracellular signal molecule and this causes them to express qualitatively different genes. Graded quantitative information is thereby converted into qualitative information, This provides a mechanism which can generate sequential zones of different cell types, for example, along the embryo’s main axis. Wnts, retinoids and FGF’s have been proposed to mediate gradients in the main body axis.
b/ Timing mechanisms. A biological clock can also generate a spatial pattern. A key example here is the somitogenesis clock, a mechanism in which an oscillating system of gene expression is measured off in time and space to deliver repeating units (somites) along the main body axis
2/ The Hox module: One way of generating qualitatively different zones along an axis is where a chromosomal complex acts as a functional unit such that the physical order of the genes in the complex provides information for timing and/or for spatial location of gene expression. The classical examples here are the Hox gene complexes. We will examine how Hox complexes are regulated and how these function in delivering patterning information along the main body axis.
3/ Coordinated cell movements. One of the least well investigated aspects of embryonic development is how embryos develop their shape (morphogenesis) via coordinated cell movements. We will investigate fundamental principles underlying this aspect during main body axis development. An exciting new discovery here is that directional cell movement to a signal source (chemotaxis) mediates morphogenesis of the embryo during axis formation
Markus Affolter, Jacqueline Deschamps, Denis Duboule, Antony Durston, Stephen Gaunt, Walter Gehring, Ray Keller, Hans Meinhardt, Olivier Pourquie, Alain Prochiantz, Claudio Stern, Cornelis Weijer, Lewis Wolpert.
Participation is limited to 60. If you are interested in participating, please contact:
Martje Kruk, Lorentz Center, University of Leiden. Email: Kruk@lorentzcenter.nl