title: Repulsive guidance molecule a regulates hippocampal mossy fiber branching in vitro.
abstract: Repulsive guidance molecule a (RGMa), which binds to its receptor neogenin, has been well determined as a repulsive axon guidance molecule. However, whether RGMa affects the growth of hippocampal mossy fibers, the axons of dentate granule cells, has been unknown. In the present study, we found that the primary neurons in the hippocampus express both RGMa and neogenin in the postnatal rats. To examine the role of RGMa in the mossy fiber growth, the morphology of granule cells was clearly visualized by transfecting membrane-targeted green fluorescent protein using a single-cell electroporation method in cultured hippocampal slices. In the slice cultures, we found that intrinsic RGMa is required to inhibit excess branching of the hippocampal mossy fibers. Furthermore, hyperexcitability-induced aberrant branching of the mossy fibers in the cultured slices was blocked by applying the recombinant RGMa protein. Therefore, this study suggests that RGMa regulates the proper axonal branching of hippocampal mossy fibers.
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Shibata
authors.forename: Soichiro
authors.initials: S
authors.lastname: Nakahara
authors.forename: Emi
authors.initials: E
authors.lastname: Shimizu
authors.forename: Toshihide
authors.initials: T
authors.lastname: Yamashita
authors.forename: Norio
authors.initials: N
authors.lastname: Matsuki
authors.forename: Ryuta
authors.initials: R
authors.lastname: Koyama
mesh_terms: D000818:Animals; D018274:Electroporation; D058851:GPI-Linked Proteins; D015151:Immunoblotting; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000378:metabolism*; D019599:Mossy Fibers, Hippocampal / Q000254:growth & development*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000166:cytology; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C502259:RGM protein, rat