The repulsive guidance molecule RGMa is involved in the formation of afferent connections in the dentate gyrus.
In the developing dentate gyrus, afferent fiber projections terminate in distinct laminas. This relies on an accurately regulated spatiotemporal network of guidance molecules. Here, we have analyzed the functional role of the glycosylphosphatidylinositol (GPI)-anchored repulsive guidance molecule RGMa. In situ hybridization in embryonic and postnatal brain showed expression of RGMa in the cornu ammonis and hilus of the hippocampus. In the dentate gyrus, RGM immunostaining was confined to the inner molecular layer, whereas the outer molecular layers targeted by entorhinal fibers remained free. To test the repulsive capacity of RGMa, different setups were used: the stripe and explant outgrowth assays with recombinant RGMa, and entorhino-hippocampal cocultures incubated either with a neutralizing RGMa antibody (Ab) or with the GPI anchor-digesting drug phosphatidylinositol-specific phospholipase C. Entorhinal axons were clearly repelled by RGMa in the stripe and outgrowth assays. After disrupting the RGMa function, the specific laminar termination pattern in entorhino-hippocampal cocultures was lost, and entorhinal axons entered inappropriate hippocampal areas. Our data indicate an important role of RGMa for the layer-specific termination of the perforant pathway as a repulsive signal that compels entorhinal fibers to stay in their correct target zone.
Brinks
Henriette
H
Neuroscience Research Center, Institute of Cell Biology and Neurobiology, Charité Central Campus, 10098 Berlin, Germany.
Conrad
Sabine
S
Vogt
Johannes
J
Oldekamp
Judit
J
Sierra
Ana
A
Deitinghoff
Lutz
L
Bechmann
Ingo
I
Alvarez-Bolado
Gonzalo
G
Heimrich
Bernd
B
Monnier
Philippe P
PP
Mueller
Bernhard K
BK
Skutella
Thomas
T
D000344:Afferent Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D018891:Dentate Gyrus / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D018728:Entorhinal Cortex / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D058851:GPI-Linked Proteins; D006624:Hippocampus / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008024:Ligands; D051379:Mice; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D016501:Neurites / Q000502:physiology; D014162:Transfection
D000906:Antibodies; D058851:GPI-Linked Proteins; D008024:Ligands; D009419:Nerve Tissue Proteins; C483496:Rgma protein, mouse