Reconstitution of morphogen shuttling circuits
Developing tissues form spatial patterns by establishing concentration gradients of diffusible signaling proteins called morphogens. The bone morphogenetic protein (BMP) morphogen pathway uses a family of extracellular modulators to reshape signaling gradients by actively "shuttling" ligands to different locations. It has remained unclear what circuits are sufficient to enable shuttling, what other patterns they can generate, and whether shuttling is evolutionarily conserved. Here, using a synthetic, bottom-up approach, we compared the spatiotemporal dynamics of different extracellular circuits. Three proteins—Chordin, Twsg, and the BMP-1 protease—successfully displaced gradients by shuttling ligands away from the site of production. A mathematical model explained the different spatial dynamics of this and other circuits. Last, combining mammalian and Drosophila components in the same system suggests that shuttling is a conserved capability. Together, these results reveal principles through which extracellular circuits control the spatiotemporal dynamics of morphogen signaling.
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© 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).
We thank P. Li and S. Wang for sharing sequential plating protocol and codes for analyzing gradients, as well as for many suggestions on the project; H. Klumpe for sharing the BMP receiver cell line; F. Ding, E. Hui and A. Curtis for scientific inputs on the projects; N. Barkai, U. Alon, A. Eldar, J. Briscoe, B. Shilo, D. Sprinzak, A. McMahon, and M. Wilson for insights and discussions; J. Bois for teaching and sharing Caltech BE150 course materials for mathematical modeling; Z. Chen, J. M. Linton., Y. Takei, D. Li, B. Gu., and D. M. Chadly for critical feedback on the manuscript; and other members of the Elowitz laboratory for scientific input and support. J.S.M. was affiliated with California Institute of Technology at the time of this study and is currently affiliated with Novo Ventures. N.N. was affiliated with California Institute of Technology at the time of this study and is currently affiliated with the Department of Systems Biology, Harvard Medical School. R.Z. was affiliated with California Institute of Technology at the time of this study and is currently affiliated with Gladstone-UCSF Institute of Genomic Immunology and Department of Genetics, Stanford University. M.B.E. is a Howard Hughes Medical Institute investigator.
This work was supported by the NSF (EFRI 1137269) and the Institute for Collaborative Biotechnologies through grant W911NF-09-0001 from the U.S. Army Research Office. The content of the information does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred. This work was also supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the NIH under award number F32AR067103 (to J.S.M.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH; N.N. was a Howard Hughes Medical Institute International Student Research fellow; J.G. was supported by the Boehringer Ingelheim Fonds PhD fellowship. This article is subject to HHMI's Open Access to Publication policy. HHMI laboratory heads have previously granted a nonexclusive CC BY 4.0 license to the public and a sublicensable license to HHMI in their research articles. Pursuant to those licenses, the author-accepted manuscript of this article can be made freely available under a CC BY 4.0 license immediately upon publication.
R.Z., J.S.M., N.N., and M.B.E. conceived the project. R.Z., L.A.S., J.S.M., N.N., J.G., and M.B.E. designed the experiments. R.Z., L.A.S., J.S.M., N.N., and J.G. performed the experiments. R.Z., L.A.S., J.S.M., N.N., J.G., and M.B.E. analyzed data. R.Z., J.S.M., and M.B.E. did mathematical modeling. R.Z., L.A.S., and M.B.E. wrote the manuscript with input from all authors.
All DNA constructs (table S2) and cell lines (table S3) are available from M.B.E. or through the Addgene repository under a material transfer agreement with California Institute of Technology. All data generated and all the computational and data analysis and modeling codes used in the current study are available at data.caltech.edu/records/0sdrn-73r13. All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.
Conflict of Interest
The authors declare that they have no competing interests.