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Int J Dev Biol 2023 Jan 01;673:79-90. doi: 10.1387/ijdb.230123rw.
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Polarized contact behavior in directionally migrating Xenopus gastrula mesendoderm.

Nagel M , Winklbauer R .

The control of cell-cell adhesion and detachment is essential for collective migration and cell rearrangement. Here, we have used the contact behavior of Xenopus gastrula mesoderm explants migrating directionally on ectoderm conditioned substratum to study the regulation of active cell-cell detachment. When colliding laterally, explants repelled each other, whereas they fused front-to-back when aligned in the direction of migration. For this mesoderm polarization by the substratum, we identified three control modules. First, PDGF-A signaling normally suppresses contact-induced collapse of lamellipodia in a polarized manner. Disruption of PDGF-A function, or of Xwnt6, decreased the polarization of explant contact behavior. Second, the Wnt receptor Xfz7 acted upstream of the kinase Pak1 to control explant fusion independently of PDGF-A-promoted lamellipodia stability. Third, ephrinB1 acted with Dishevelled (Dvl) in front-to-back explant fusion. The second and third modules have been identified previously as regulators of tissue separation at the ectoderm-mesoderm boundary. On non-polarizing, fibronectin-coated substratum, they controlled repulsion between explants in the same way as between tissues during boundary formation. However, explant repulsion/fusion responses were reversed on conditioned substratum by the endogenous guidance cues that also control oriented contact inhibition of lamellipodia. Together, control modules and substratum-bound guidance cues combine preferential front-back adhesion and diminished lateral adhesion of cells to promote collective directional mesoderm migration.

PubMed ID: 37732810
Article link: Int J Dev Biol

Species referenced: Xenopus laevis
Genes referenced: bcr dvl1 dvl2 efnb1 fn1 fzd7 fzd8 pak1 pdgfa wnt11 wnt5a wnt6
GO keywords: cell adhesion [+]
Morpholinos: dvl1 MO3 efnb1 MO1 fzd7 MO4 prickle1 MO1 wnt5a MO1 wnt6 MO3

Article Images: [+] show captions