First published online September 9, 2004
Development 131, 1905e (2004)
© The Company of Biologists Limited
Setting morphogen gradients
Morphogen gradients provide cells in developing organisms with essential
positional information. But do gradients form through extracellular morphogen
diffusion alone or is intracellular trafficking also involved? On p.
4843, Kruse and
colleagues address this controversial issue and conclude that in the
Drosophila developing wing epithelium, extracellular diffusion is not
sufficient to establish the Decapentaplegic (Dpp) morphogen gradient.
Transient `shadows' of Dpp signalling are known to occur behind clones of
endocytosis-defective cells, and the researchers calculate that if Dpp
gradients were established through diffusion alone, the endocytosis-defective
cells would have to upregulate Dpp receptor cell surface expression to cause
these shadows. Yet, when Kruse et al. use specific antibodies to measure Dpp
receptors on such cells, there is no receptor upregulation. Further
experiments are now needed to determine the relative importance of different
transport methods for Dpp spreading, say the researchers.
Related articles in Development:
- Dpp gradient formation by dynamin-dependent endocytosis: receptor trafficking and the diffusion model
- Karsten Kruse, Periklis Pantazis, Tobias Bollenbach, Frank Jülicher, and Marcos González-Gaitán
Development 2004 131: 4843-4856.
[Abstract]
[Full Text]
