Interpretation of the FGF8 morphogen gradient is regulated by endocytic trafficking

Abstract

The cellular mechanisms that modulate morphogen gradient interpretation in tissue have been debated. In vivo fluorescence correlation spectroscopy and automated image analysis show that modulation of endocytic trafficking affects FGF8 target-gene expression without an effect on the FGF8 gradient itself. Forty years ago, it was proposed that during embryonic development and organogenesis, morphogen gradients provide positional information to the individual cells within a tissue leading to specific fate decisions1,2. Recently, much insight has been gained into how such morphogen gradients are formed and maintained; however, which cellular mechanisms govern their interpretation within target tissues remains debated3. Here we used in vivo fluorescence correlation spectroscopy and automated image analysis to assess the role of endocytic sorting dynamics on fibroblast growth factor 8 (Fgf8) morphogen gradient interpretation. By interfering with the function of the ubiquitin ligase Cbl, we found an expanded range of Fgf target gene expression and a delay of Fgf8 lysosomal transport. However, the extracellular Fgf8 morphogen gradient remained unchanged, indicating that the observed signalling changes are due to altered gradient interpretation. We propose that regulation of morphogen signalling activity through endocytic sorting allows fast feedback-induced changes in gradient interpretation during the establishment of complex patterns.

Cite this article

Nowak, M., Machate, A., Yu, S. et al. Interpretation of the FGF8 morphogen gradient is regulated by endocytic trafficking. Nat Cell Biol 13, 153–158 (2011). https://doi.org/10.1038/ncb2155

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