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ECB-ART-50709
Curr Biol 2021 Nov 20;3124:5633-5641.e4. doi: 10.1016/j.cub.2021.10.022.
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Polarized Dishevelled dissolution and reassembly drives embryonic axis specification in sea star oocytes.

Swartz SZ , Tan TH , Perillo M , Fakhri N , Wessel GM , Wikramanayake AH , Cheeseman IM .


Abstract
The organismal body axes that are formed during embryogenesis are intimately linked to intrinsic asymmetries established at the cellular scale in oocytes.1 However, the mechanisms that generate cellular asymmetries within the oocyte and then transduce that polarity to organismal scale body axes are poorly understood outside of select model organisms. Here, we report an axis-defining event in meiotic oocytes of the sea star Patiria miniata. Dishevelled (Dvl) is a cytoplasmic Wnt pathway effector required for axis development in diverse species,2-4 but the mechanisms governing its function and distribution remain poorly defined. Using time-lapse imaging, we find that Dvl localizes uniformly to puncta throughout the cell cortex in Prophase I-arrested oocytes but becomes enriched at the vegetal pole following meiotic resumption through a dissolution-reassembly mechanism. This process is driven by an initial disassembly phase of Dvl puncta, followed by selective reformation of Dvl assemblies at the vegetal pole. Rather than being driven by Wnt signaling, this localization behavior is coupled to meiotic cell cycle progression and influenced by Lamp1+ endosome association and Frizzled receptors pre-localized within the oocyte cortex. Our results reveal a cell cycle-linked mechanism by which maternal cellular polarity is transduced to the embryo through spatially regulated Dvl dynamics.

PubMed ID: 34739818
PMC ID: PMC8692449
Article link: Curr Biol
Grant support: [+]

Genes referenced: LOC584189
Antibodies: LOC584189 Ab4 LOC590586 Ab3
Morpholinos: LOC584189 MO2 fzd2 MO3

References [+] :
Bienz, Head-to-Tail Polymerization in the Assembly of Biomolecular Condensates. 2020, Pubmed