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BioMed Research International
Volume 2016 (2016), Article ID 2456062, 12 pages
http://dx.doi.org/10.1155/2016/2456062
Research Article

Neurotrophin, p75, and Trk Signaling Module in the Developing Nervous System of the Marine Annelid Platynereis dumerilii

1Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
2Institute for Biological and Medical Imaging and Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 München, Germany

Received 11 September 2015; Revised 30 November 2015; Accepted 1 December 2015

Academic Editor: Sidi Chen

Copyright © 2016 Antonella Lauri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In vertebrates, neurotrophic signaling plays an important role in neuronal development, neural circuit formation, and neuronal plasticity, but its evolutionary origin remains obscure. We found and validated nucleotide sequences encoding putative neurotrophic ligands (neurotrophin, NT) and receptors (Trk and p75) in two annelids, Platynereis dumerilii (Errantia) and Capitella teleta (Sedentaria, for which some sequences were found recently by Wilson, 2009). Predicted protein sequences and structures of Platynereis neurotrophic molecules reveal a high degree of conservation with the vertebrate counterparts; some amino acids signatures present in the annelid Trk sequences are absent in the basal chordate amphioxus, reflecting secondary loss in the cephalochordate lineage. In addition, expression analysis of NT, Trk, and p75 during Platynereis development by whole-mount mRNA in situ hybridization supports a role of these molecules in nervous system and circuit development. These annelid data corroborate the hypothesis that the neurotrophic signaling and its involvement in shaping neural networks predate the protostome-deuterostome split and were present in bilaterian ancestors.