We analysed the role of Notch signalling during the specification of the dorsal midline in Xenopus embryos. By activating or blocking the pathway we found that Notch expands the floor plate domain of sonic hedgehog and pintallavis and represses the notochordal markers chordin and brachyury, with a concomitant reduction of the notochord size. We propose that within a population of the early organiser with equivalent potential to develop either as notochord or floor plate, Notch activation favours floor plate development at the expense of the notochord,preferentially before mid gastrula. We present evidence that sonic hedgehog down-regulates chordin, suggesting that secreted Sonic hedgehog may be involved or reinforcing the cell-fate switch executed by Notch. We also show that Notch signalling requires Presenilin to modulate this switch.
Notch activates sonic hedgehog and both are involved in the specification of dorsal midline cell-fates in Xenopus
These authors have contributed equally to this work and are listed in alphabetical order
These authors have contributed equally to this work and are listed in alphabetical order
These authors have contributed equally to this work and are listed in alphabetical order
These authors have contributed equally to this work and are listed in alphabetical order
Silvia L. López, Alejandra R. Paganelli, María V. Rosato Siri, Oscar H. Ocaña, Paula G. Franco, Andrés E. Carrasco; Notch activates sonic hedgehog and both are involved in the specification of dorsal midline cell-fates in Xenopus. Development 15 May 2003; 130 (10): 2225–2238. doi: https://doi.org/10.1242/dev.00443
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