Elsevier

Developmental Biology

Volume 382, Issue 2, 15 October 2013, Pages 496-503
Developmental Biology

The distribution of Dishevelled in convergently extending mesoderm

https://doi.org/10.1016/j.ydbio.2013.07.012Get rights and content
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Highlights

  • Bipolar enrichment of Dvl in Xenopus convergently extending mesoderm is non-specific.

  • Bulk Dvl co-localises with yolk-free-cytoplasm-filling Dextran.

  • Cortical Dvl shows monopolar enrichment in notochord–somite-boundary-directed protrusions.

  • Monopolar Dvl enrichment declines with distance from the NSB.

  • Dvl accumulation is not absolutely (at least not uniquely) coupled to protrusion.

Abstract

Convergent extension (CE) is a conserved morphogenetic movement that drives axial lengthening of the primary body axis and depends on the planar cell polarity (PCP) pathway. In Drosophila epithelia, a polarised subcellular accumulation of PCP core components, such as Dishevelled (Dvl) protein, is associated with PCP function. Dvl has long been thought to accumulate in the mediolateral protrusions in Xenopus chordamesoderm cells undergoing CE. Here we present a quantitative analysis of Dvl intracellular localisation in Xenopus chordamesoderm cells. We find that, surprisingly, accumulations previously observed at mediolateral protrusions of chordamesodermal cells are not protrusion-specific but reflect yolk-free cytoplasm and are quantitatively matched by the distribution of the cytoplasm-filling lineage marker dextran. However, separating cell cortex-associated from bulk Dvl signal reveals a statistical enrichment of Dvl in notochord–somite boundary-(NSB)-directed protrusions, which is dependent upon NSB proximity. Dvl puncta were also observed, but only upon elevated overexpression. These puncta showed no statistically significant spatial bias, in contrast to the strongly posteriorly-enriched GFP-Dvl puncta previously reported in zebrafish. We propose that Dvl distribution is more subtle and dynamic than previously appreciated and that in vertebrate mesoderm it reflects processes other than protrusion as such.

Keywords

Planar cell polarity
Dishevelled
Xenopus
Convergent extension
Localisation
Image analysis
QuimP

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1

These authors contributed equally to this work.