A direct interaction of axonin-1 with NgCAM-related cell adhesion molecule (NrCAM) results in guidance, but not growth of commissural axons.
An interaction of growth cone axonin-1 with the floor-plate NgCAM-related cell adhesion molecule (NrCAM) was shown to play a crucial role in commissural axon guidance across the midline of the spinal cord. We now provide evidence that axonin-1 mediates a guidance signal without promoting axon elongation. In an in vitro assay, commissural axons grew preferentially on stripes coated with a mixture of NrCAM and NgCAM. This preference was abolished in the presence of anti-axonin-1 antibodies without a decrease in neurite length. Consistent with these findings, commissural axons in vivo only fail to extend along the longitudinal axis when both NrCAM and NgCAM interactions, but not when axonin-1 and NrCAM or axonin-1 and NgCAM interactions, are perturbed. Thus, we conclude that axonin-1 is involved in guidance of commissural axons without promoting their growth.
Fitzli
D
D
Institute of Biochemistry, University of Zurich, Switzerland.
Stoeckli
E T
ET
Kunz
S
S
Siribour
K
K
Rader
C
C
Kunz
B
B
Kozlov
S V
SV
Buchstaller
A
A
Lane
R P
RP
Suter
D M
DM
Dreyer
W J
WJ
Sonderegger
P
P
D000818:Animals; D001369:Axons / Q000502:physiology*; D001665:Binding Sites; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules; D019062:Cell Adhesion Molecules, Neuron-Glia / Q000378:metabolism; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D058969:Contactin 2; D004627:Embryonic Induction; D020439:Growth Cones / Q000502:physiology; D005810:Multigene Family; D009434:Neural Pathways / Q000196:embryology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000601:surgery
C548674:CNTN2 protein, human; D015815:Cell Adhesion Molecules; D019062:Cell Adhesion Molecules, Neuron-Glia; D015816:Cell Adhesion Molecules, Neuronal; D058969:Contactin 2; C491152:NRCAM protein, human; D011994:Recombinant Proteins