Diverging roles for Lrp4 and Wnt signaling in neuromuscular synapse development during evolution
- Leonor Remédio1,
- Katherine D. Gribble2,
- Jennifer K. Lee1,
- Natalie Kim1,
- Peter T. Hallock1,
- Nicolas Delestrée3,4,5,
- George Z. Mentis3,4,5,
- Robert C. Froemke1,
- Michael Granato2 and
- Steven J. Burden1
- 1Molecular Neurobiology Program, Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, New York University Medical School, New York, New York 10016, USA;
- 2Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA;
- 3Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10032, USA;
- 4Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA;
- 5Department of Neurology, Columbia University, New York, New York 10032, USA
- Corresponding authors: steve.burden{at}med.nyu.edu, leonor.remedio{at}med.nyu.edu
Abstract
Motor axons approach muscles that are prepatterned in the prospective synaptic region. In mice, prepatterning of acetylcholine receptors requires Lrp4, a LDLR family member, and MuSK, a receptor tyrosine kinase. Lrp4 can bind and stimulate MuSK, strongly suggesting that association between Lrp4 and MuSK, independent of additional ligands, initiates prepatterning in mice. In zebrafish, Wnts, which bind the Frizzled (Fz)-like domain in MuSK, are required for prepatterning, suggesting that Wnts may contribute to prepatterning and neuromuscular development in mammals. We show that prepatterning in mice requires Lrp4 but not the MuSK Fz-like domain. In contrast, prepatterning in zebrafish requires the MuSK Fz-like domain but not Lrp4. Despite these differences, neuromuscular synapse formation in zebrafish and mice share similar mechanisms, requiring Lrp4, MuSK, and neuronal Agrin but not the MuSK Fz-like domain or Wnt production from muscle. Our findings demonstrate that evolutionary divergent mechanisms establish muscle prepatterning in zebrafish and mice.
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Footnotes
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Supplemental material is available for this article.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.279745.116.
- Received February 17, 2016.
- Accepted March 31, 2016.
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