TY - JOUR
T1 - New roles for Wnt and BMP signaling in neural anteroposterior patterning
AU - Polevoy, Hanna
AU - Gutkovich, Yoni E.
AU - Michaelov, Ariel
AU - Volovik, Yael
AU - Elkouby, Yaniv M.
AU - Frank, Dale
N1 - Publisher Copyright:
© 2019 The Authors
PY - 2019/6
Y1 - 2019/6
N2 - During amphibian development, neural patterning occurs via a two-step process. Spemann's organizer secretes BMP antagonists that induce anterior neural tissue. A subsequent caudalizing step re-specifies anterior fated cells to posterior fates such as hindbrain and spinal cord. The neural patterning paradigm suggests that a canonical Wnt-signaling gradient acts along the anteroposterior axis to pattern the nervous system. Wnt activity is highest in the posterior, inducing spinal cord, at intermediate levels in the trunk, inducing hindbrain, and is lowest in anterior fated forebrain, while BMP-antagonist levels are constant along the axis. Our results in Xenopus laevis challenge this paradigm. We find that inhibition of canonical Wnt signaling or its downstream transcription factors eliminates hindbrain, but not spinal cord fates, an observation not compatible with a simple high-to-low Wnt gradient specifying all fates along the neural anteroposterior axis. Additionally, we find that BMP activity promotes posterior spinal cord cell fate formation in an FGF-dependent manner, while inhibiting hindbrain fates. These results suggest a need to re-evaluate the paradigms of neural anteroposterior pattern formation during vertebrate development.
AB - During amphibian development, neural patterning occurs via a two-step process. Spemann's organizer secretes BMP antagonists that induce anterior neural tissue. A subsequent caudalizing step re-specifies anterior fated cells to posterior fates such as hindbrain and spinal cord. The neural patterning paradigm suggests that a canonical Wnt-signaling gradient acts along the anteroposterior axis to pattern the nervous system. Wnt activity is highest in the posterior, inducing spinal cord, at intermediate levels in the trunk, inducing hindbrain, and is lowest in anterior fated forebrain, while BMP-antagonist levels are constant along the axis. Our results in Xenopus laevis challenge this paradigm. We find that inhibition of canonical Wnt signaling or its downstream transcription factors eliminates hindbrain, but not spinal cord fates, an observation not compatible with a simple high-to-low Wnt gradient specifying all fates along the neural anteroposterior axis. Additionally, we find that BMP activity promotes posterior spinal cord cell fate formation in an FGF-dependent manner, while inhibiting hindbrain fates. These results suggest a need to re-evaluate the paradigms of neural anteroposterior pattern formation during vertebrate development.
KW - BMP signaling
KW - Xenopus
KW - canonical Wnt signaling
KW - hindbrain and spinal cord
KW - neural anteroposterior patterning
UR - http://www.scopus.com/inward/record.url?scp=85063674887&partnerID=8YFLogxK
U2 - 10.15252/embr.201845842
DO - 10.15252/embr.201845842
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C2 - 30936121
AN - SCOPUS:85063674887
SN - 1469-221X
VL - 20
JO - EMBO Reports
JF - EMBO Reports
IS - 6
M1 - e45842
ER -