ABSTRACT
The differentiation of tissues and organs requires that cells exchange information in space and time. Spatial information is often conveyed by morphogens: molecules that disperse across receiving cells to generate signalling gradients. Cells translate such concentration gradients into space-dependent patterns of gene expression and cellular behaviour. But could morphogen gradients also convey developmental time? Here, by investigating the developmental role of Hh on a component of the Drosophila visual system, the ocellar retina, we have discovered that ocellar cells use the non-linear gradient of Hh as a temporal cue, collectively performing the biological equivalent of a mathematical logarithmic transformation. In this way, a morphogen diffusing from a non-moving source is decoded as a wave of differentiating photoreceptors that travels at constant speed throughout the retinal epithelium.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: D.G.M., F.C.; Methodology: D.G.-M., T.N.; Software: D.G.M.; Formal analysis: T.N., D.G.M.; Investigation: D.G.-M., A.I., F.C.; Resources: P.S.P.; Data curation: D.G.-M., F.C.; Writing - original draft: D.G.M., F.C.; Writing - review & editing: D.G.-M., T.N., D.G.M., F.C.; Visualization: D.G.-M., T.N., A.I., F.C.; Supervision: F.C.; Project administration: F.C.; Funding acquisition: D.G.M., F.C.
Funding
Research was funded through grants BFU2015-66040-P and MDM-2016-0687 (to F.C.) and BFU2014-53299-P (to D.G.M.) from the Ministerio de Ciencia, Innovación y Universidades (Spain).
Supplementary information
Supplementary information available online at http://dev.biologists.org/lookup/doi/10.1242/dev.176933.supplemental
- Received February 14, 2019.
- Accepted March 19, 2019.
Article navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Other journals from The Company of Biologists
Kathryn Virginia Anderson (1952-2020)
Developmental geneticist Kathryn Anderson passed away at home on 30 November 2020. Tamara Caspary, a former postdoc and friend, remembers Kathryn and her remarkable contribution to developmental biology.
Zooming into 2021
In a new Editorial, Editor-in-Chief James Briscoe and Executive Editor Katherine Brown reflect on the triumphs and tribulations of the last 12 months, and look towards a hopefully calmer and more predictable year.
Read & Publish participation extends worldwide
Over 60 institutions in 12 countries are now participating in our Read & Publish initiative. Here, James Briscoe explains what this means for his institution, The Francis Crick Institute. Find out more and view our full list of participating institutions.
Upcoming special issues
Imaging Development, Stem Cells and Regeneration
Submission deadline: 30 March 2021
Publication: mid-2021
The Immune System in Development and Regeneration
Guest editors: Florent Ginhoux and Paul Martin
Submission deadline: 1 September 2021
Publication: Spring 2022
Both special issues welcome Review articles as well as Research articles, and will be widely promoted online and at key global conferences.
Development presents...
Our successful webinar series continues into 2021, with early-career researchers presenting their papers and a chance to virtually network with the developmental biology community afterwards. Sign up to join our next session:
10 February
Time: 13:00 (GMT)
Chaired by: preLights