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XB-ART-42478
Dev Biol February 15, 2011; 350 (2): 441-50.
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The involvement of Eph-Ephrin signaling in tissue separation and convergence during Xenopus gastrulation movements.

Park EC , Cho GS , Kim GH , Choi SC , Han JK .


Abstract
In Xenopus gastrulation, the involuting mesodermal and non-involuting ectodermal cells remain separated from each other, undergoing convergent extension. Here, we show that Eph-ephrin signaling is crucial for the tissue separation and convergence during gastrulation. The loss of EphA4 function results in aberrant gastrulation movements, which are due to selective inhibition of tissue constriction and separation. At the cellular levels, knockdown of EphA4 impairs polarization and migratory activity of gastrulating cells but not specification of their fates. Importantly, rescue experiments demonstrate that EphA4 controls tissue separation via RhoA GTPase in parallel to Fz7 and PAPC signaling. In addition, we show that EphA4 and its putative ligand, ephrin-A1 are expressed in a complementary manner in the involuting mesodermal and non-involuting ectodermal layers of early gastrulae, respectively. Depletion of ephrin-A1 also abrogates tissue separation behaviors. Therefore, these results suggest that Eph receptor and its ephrin ligand might mediate repulsive interaction for tissue separation and convergence during early Xenopus gastrulation movements.

PubMed ID: 21147090
Article link: Dev Biol


Species referenced: Xenopus
Genes referenced: actl6a adam10 bcr cdc42 chrd.1 efna1 epha4 fzd7 gal.2 gsc pcdh8.2 rac1 rhoa tbxt
Morpholinos: efna1 MO1 epha4 MO2


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