RT Journal Article
SR Electronic
T1 Nodal and <em>churchill1</em> position the expression of a notch ligand during <em>Xenopus</em> germ layer segregation
JF Life Science Alliance
JO Life Sci. Alliance
FD Life Science Alliance LLC
SP e202201693
DO 10.26508/lsa.202201693
VO 5
IS 12
A1 María Belén Favarolo
A1 Diego R Revinski
A1 Matías J Garavaglia
A1 Silvia L López
YR 2022
UL https://www.life-science-alliance.org/content/5/12/e202201693.abstract
AB In vertebrates, Nodal signaling plays a major role in endomesoderm induction, but germ layer delimitation is poorly understood. In avian embryos, the neural/mesoderm boundary is controlled by the transcription factor CHURCHILL1, presumably through the repressor ZEB2, but there is scarce knowledge about its role in other vertebrates. During amphibian gastrulation, Delta/Notch signaling refines germ layer boundaries in the marginal zone, but it is unknown the place this pathway occupies in the network comprising Churchill1 and Nodal. Here, we show that Xenopus churchill1 is expressed in the presumptive neuroectoderm at mid-blastula transition and during gastrulation, upregulates zeb2, prevents dll1 expression in the neuroectoderm, and favors neuroectoderm over endomesoderm development. Nodal signaling prevents dll1 expression in the endoderm but induces it in the presumptive mesoderm, from where it activates Notch1 and its target gene hes4 in the non-involuting marginal zone. We propose a model where Nodal and Churchill1 position Dll1/Notch1/Hes4 domains in the marginal zone, ensuring the delimitation between mesoderm and neuroectoderm.