Quantitative analyses reveal extracellular dynamics of Wnt ligands in Xenopus embryos
- National Institute for Basic Biology, Japan
- RIKEN, Japan
- University of Tokyo, Japan
- Kyoto University, Japan
- National Institutes of Natural Sciences, Japan
Abstract
The mechanism of intercellular transport of Wnt ligands is still a matter of debate. To better understand this issue, we examined the distribution and dynamics of Wnt8 in Xenopus embryos. While Venus-tagged Wnt8 was found on the surfaces of cells close to Wnt-producing cells, we also detected its dispersal over distances of 15 cell diameters. A combination of fluorescence correlation spectroscopy and quantitative imaging suggested that only a small proportion of Wnt8 ligands diffuses freely, whereas most Wnt8 molecules are bound to cell surfaces. Fluorescence decay after photoconversion showed that Wnt8 ligands bound on cell surfaces decrease exponentially, suggesting a dynamic exchange of bound forms of Wnt ligands. Mathematical modelling based on this exchange recapitulates a graded distribution of bound, but not free, Wnt ligands. Based on these results, we propose that Wnt distribution in tissues is controlled by a dynamic exchange of its abundant bound and rare free populations.
Data availability
Sequence data for anti-HA IgG genes have been deposited in Genbank/DDBJ under accession codes LC522514 and LC522515.
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Author details
Funding
Japan Science and Technology Agency (JPMJPR194B)
- Yusuke Mii
Japan Society for the Promotion of Science (24870031)
- Yusuke Mii
Japan Society for the Promotion of Science (15K14532)
- Yusuke Mii
Japan Society for the Promotion of Science (18K14720)
- Yusuke Mii
Japan Society for the Promotion of Science (17K19418)
- Shinji Takada
Japan Society for the Promotion of Science (24657147)
- Yusuke Mii
- Masanori Taira
National Institutes of Natural Sciences (1311608,01311801)
- Yusuke Mii
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All experiments using Xenopus laevis were approved by the Institutional Animal Care and Use Committee, National Institutes of Natural Sciences (Permit Number 18A038, 19A062, 20A053), or the Office for Life Science Research Ethics and Safety, University of Tokyo.
Copyright
© 2021, Mii et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Quantitative analyses reveal extracellular dynamics of Wnt ligands in Xenopus embryos
eLife 10:e55108.
https://doi.org/10.7554/eLife.55108
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