Hairy 2A promotes floor plate fates at expense of the notochord, blocking involution in the Xenopus organiser

LÓPEZ S; ROSATO SIRI, MV; PAGANELLI, A.R; FRANCO, P.G; RAIMONDI, P; CARRASCO A

San Francisco USA

Congreso; Society for developmental Biology, 64th annual meeting; 2005

Society for developmental Biology

We have previously shown that the early Xenopus organiser contains cells equally potent to give rise to notochord or floor plate, and that Notch signalling triggers a binary decision, favouring the floor plate fate at the expense of the notochord. Now, we present evidence that Delta1 is the ligand that triggers the binary switch, which is executed through the Notch-mediated activation of hairy2a in the surrounding cells within the organiser, impeding their involution through the blastopore and promoting their incorporation into the hairy2a+ notoplate precursors (future floor-plate cells) in the dorsal non-involuting marginal zone.