First published online September 28, 2006
Development 133, 2003e (2006)
© The Company of Biologists Limited
Caudal: an ancestral master organiser
The establishment of the anteroposterior axis is an important early event
in embryogenesis. Many of the molecular components of this process are
conserved through evolution. However, Bicoid - the master organiser of
anterior development in Drosophila - is not present in non-dipteran
insects. So, to study the evolution of body plan patterning, Olesnicky and
co-workers have turned to the wasp Nasonia (see
p. 3973). Wasps lack
Bicoid but their embryos are patterned completely within a syncytial
environment like fly embryos. The researchers report that a gradient of
localised caudal mRNA directs posterior patterning in
Nasonia embryos in contrast to Drosophila embryos, in which
the translational repression of caudal mRNA by Bicoid establishes a
gradient of Caudal protein. The researchers also show that Nasonia
caudal activates the expression of gap genes, which then activate
pair-rule gene expression; in Drosophila, caudal mostly regulates
pair-rule gene expression. These results suggest that caudal is an
ancestral master organiser of patterning but that its role has been reduced in
dipterans.
Related articles in Development:
- A caudal mRNA gradient controls posterior development in the wasp Nasonia
- Eugenia C. Olesnicky, Ava E. Brent, Lori Tonnes, Megan Walker, Mary Anne Pultz, David Leaf, and Claude Desplan
Development 2006 133: 3973-3982.
[Abstract]
[Full Text]
