Spatiotemporal expression of repulsive guidance molecules (RGMs) and their receptor neogenin in the mouse brain

PLoS One. 2013;8(2):e55828. doi: 10.1371/journal.pone.0055828. Epub 2013 Feb 14.

Abstract

Neogenin has been implicated in a variety of developmental processes such as neurogenesis, neuronal differentiation, apoptosis, migration and axon guidance. Binding of repulsive guidance molecules (RGMs) to Neogenin inhibits axon outgrowth of different neuronal populations. This effect requires Neogenin to interact with co-receptors of the uncoordinated locomotion-5 (Unc5) family to activate downstream Rho signaling. Although previous studies have reported RGM, Neogenin, and/or Unc5 expression, a systematic comparison of RGM and Neogenin expression in the developing nervous system is lacking, especially at later developmental stages. Furthermore, information on RGM and Neogenin expression at the protein level is limited. To fill this void and to gain further insight into the role of RGM-Neogenin signaling during mouse neural development, we studied the expression of RGMa, RGMb, Neogenin and Unc5A-D using in situ hybridization, immunohistochemistry and RGMa section binding. Expression patterns in the primary olfactory system, cortex, hippocampus, habenula, and cerebellum were studied in more detail. Characteristic cell layer-specific expression patterns were detected for RGMa, RGMb, Neogenin and Unc5A-D. Furthermore, strong expression of RGMa, RGMb and Neogenin protein was found on several major axon tracts such as the primary olfactory projections, anterior commissure and fasciculus retroflexus. These data not only hint at a role for RGM-Neogenin signaling during the development of different neuronal systems, but also suggest that Neogenin partners with different Unc5 family members in different systems. Overall, the results presented here will serve as a framework for further dissection of the role of RGM-Neogenin signaling during neural development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / growth & development
  • Brain / metabolism*
  • Brain / ultrastructure
  • COS Cells
  • Cell Adhesion Molecules, Neuronal
  • Chlorocebus aethiops
  • GPI-Linked Proteins / analysis
  • GPI-Linked Proteins / genetics
  • Gene Expression Regulation, Developmental
  • HEK293 Cells
  • Humans
  • Membrane Proteins / analysis*
  • Membrane Proteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Nerve Tissue Proteins / analysis*
  • Nerve Tissue Proteins / genetics

Substances

  • Cell Adhesion Molecules, Neuronal
  • GPI-Linked Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Rgma protein, mouse
  • Rgmb protein, mouse
  • neogenin

Grants and funding

This work was funded by the Human Frontier Science Program Organization (Career Development Award), Hersenstichting, and The Netherlands Organization for Health Research and Development (VIDI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.