Quantitative analyses reveal extracellular dynamics of Wnt ligands in Xenopus embryos
Quantitative analyses reveal extracellular dynamics of Wnt ligands in Xenopus embryos
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定量分析揭示非洲爪蟾胚胎中 Wnt 配体的细胞外动力学
DOI：
10.1101/2020.02.20.957860
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Taira Masanori
中科院分区：
文献类型：
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作者：
Mii Yusuke;Nakazato Kenichi;Pack Chan-Gi;Sako Yasushi;Mochizuki Atsushi;Takada Shinji;Taira Masanori
Wnt配体的细胞间转运机制仍然是一个有争议的问题。为了更好地理解这个问题，我们研究了Wnt 8在Xenopus胚胎中的分布和动态。虽然在靠近Wnt产生细胞的细胞表面发现了Venus标记的Wnt 8，但我们还检测到它在15个细胞直径的距离上的分散。荧光相关光谱和定量成像的组合表明，只有一小部分Wnt 8配体自由扩散，而大多数Wnt 8分子结合到细胞表面。光转化后的荧光衰减表明，结合在细胞表面上的Wnt 8配体呈指数下降，表明结合形式的Wnt配体的动态交换。基于这种交换的数学建模概括了结合的而不是游离的Wnt配体的分级分布。基于这些结果，我们提出Wnt在组织中的分布是由其丰富的结合群体和稀有的自由群体的动态交换控制的。
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 inXenopusembryos. 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 modeling 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.