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Neurolin Ig domain 2 participates in retinal axon guidance and Ig domains 1 and 3 in fasciculation.

Leppert CA, Diekmann H, Paul C, Laessing U, Marx M, Bastmeyer M, Stuermer CA - J. Cell Biol. (1999)

Bottom Line: Repeated intraocular injections of a mAb against Ig domain 2 disturb the disk-directed growth: axons grow in aberrant routes and fail to reach the optic disk, but remain fasciculated. mAbs against Ig domains 1 and 3 disturb the formation of tight fascicles. mAb against Ig domain 2 significantly increases the incidence of growth cone departure from the disk-oriented fascicle track, while mAbs against Ig domains 1 and 3 do not.This was demonstrated by time-lapse videorecording of labeled growth cones.Thus, Ig domain 2 of neurolin is apparently essential for growth cone guidance towards the disk, presumably by being part of a receptor (or complex) for an axon guidance component.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Konstanz, D-78457 Konstanz, Germany.

ABSTRACT
The optic disk-directed growth of retinal ganglion cell axons is markedly disturbed in the presence of polyclonal antineurolin antibodies, which mildly affect fasciculation (Ott, H., M. Bastmeyer, and C.A.O. Stuermer, 1998. J. Neurosci. 18:3363-3372). New monoclonal antibodies (mAbs) against goldfish neurolin, an immunoglobulin (Ig) superfamily cell adhesion/recognition molecule with five Ig domains, were generated to assign function (guidance versus fasciculation) to specific Ig domains. By their ability or failure to recognize Chinese hamster ovary cells expressing recombinant neurolin with deletions of defined Ig domains, mAbs were identified as being directed against Ig domains 1, 2, or 3, respectively. Repeated intraocular injections of a mAb against Ig domain 2 disturb the disk-directed growth: axons grow in aberrant routes and fail to reach the optic disk, but remain fasciculated. mAbs against Ig domains 1 and 3 disturb the formation of tight fascicles. mAb against Ig domain 2 significantly increases the incidence of growth cone departure from the disk-oriented fascicle track, while mAbs against Ig domains 1 and 3 do not. This was demonstrated by time-lapse videorecording of labeled growth cones. Thus, Ig domain 2 of neurolin is apparently essential for growth cone guidance towards the disk, presumably by being part of a receptor (or complex) for an axon guidance component.

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Ig domains 1 and 3 of neurolin contribute to axonal fasciculation in vivo. (A) Wholemount of a retina injected with  mAb N100 against Ig domain 3. The positions of B and D are indicated by rectangles. (B) Dorsal segment of the retina in A. The  directed growth of young RGC axons along fascicles from the  retinal margin (rm) to the optic disk (od) is maintained and is as  orderly as in control retinae. In retinae injected with mAb N850  against Ig domain 1 (C) or mAb N100 against Ig domain 3 (D)  young RGC axons in fascicles fail to adhere tightly to each other.  The distance between neighboring axons is increased compared  to controls (F). (E) mAb N518 against domain 2 does not interfere with tight fasciculation, but causes pathfinding errors of  young RGC axons (arrow). C–F are from the temporal retina,  oriented with the retinal margin to the right, and the optic disk to  the left. Bars, B, 300 μm; C–F, 100 μm.
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Figure 3: Ig domains 1 and 3 of neurolin contribute to axonal fasciculation in vivo. (A) Wholemount of a retina injected with mAb N100 against Ig domain 3. The positions of B and D are indicated by rectangles. (B) Dorsal segment of the retina in A. The directed growth of young RGC axons along fascicles from the retinal margin (rm) to the optic disk (od) is maintained and is as orderly as in control retinae. In retinae injected with mAb N850 against Ig domain 1 (C) or mAb N100 against Ig domain 3 (D) young RGC axons in fascicles fail to adhere tightly to each other. The distance between neighboring axons is increased compared to controls (F). (E) mAb N518 against domain 2 does not interfere with tight fasciculation, but causes pathfinding errors of young RGC axons (arrow). C–F are from the temporal retina, oriented with the retinal margin to the right, and the optic disk to the left. Bars, B, 300 μm; C–F, 100 μm.

Mentions: After injections of either mAb N850 or mAb N100 (requiring the presence of Ig domains 1 and 3, respectively), the pattern of peripherocentrally oriented fascicles was preserved (Fig. 3, A and B) but the tight adherence of young axons within their fascicles was disturbed. The association of axons in loose bundles is illustrated in Fig. 3, C and D, and compared to the tighter fascicles in normal control (Fig. 3 F) and mAb N518 (Fig. 3 E) injected retinae. The defasciculation effect was most pronounced in the temporal retina and occurred in 8 out of 10 retinae after mAb N850 injections. Three retinae showed occasional (6–10) misoriented axon fascicles in the dorsal half of the retina, and two retinae appeared entirely normal.


Neurolin Ig domain 2 participates in retinal axon guidance and Ig domains 1 and 3 in fasciculation.

Leppert CA, Diekmann H, Paul C, Laessing U, Marx M, Bastmeyer M, Stuermer CA - J. Cell Biol. (1999)

Ig domains 1 and 3 of neurolin contribute to axonal fasciculation in vivo. (A) Wholemount of a retina injected with  mAb N100 against Ig domain 3. The positions of B and D are indicated by rectangles. (B) Dorsal segment of the retina in A. The  directed growth of young RGC axons along fascicles from the  retinal margin (rm) to the optic disk (od) is maintained and is as  orderly as in control retinae. In retinae injected with mAb N850  against Ig domain 1 (C) or mAb N100 against Ig domain 3 (D)  young RGC axons in fascicles fail to adhere tightly to each other.  The distance between neighboring axons is increased compared  to controls (F). (E) mAb N518 against domain 2 does not interfere with tight fasciculation, but causes pathfinding errors of  young RGC axons (arrow). C–F are from the temporal retina,  oriented with the retinal margin to the right, and the optic disk to  the left. Bars, B, 300 μm; C–F, 100 μm.
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Figure 3: Ig domains 1 and 3 of neurolin contribute to axonal fasciculation in vivo. (A) Wholemount of a retina injected with mAb N100 against Ig domain 3. The positions of B and D are indicated by rectangles. (B) Dorsal segment of the retina in A. The directed growth of young RGC axons along fascicles from the retinal margin (rm) to the optic disk (od) is maintained and is as orderly as in control retinae. In retinae injected with mAb N850 against Ig domain 1 (C) or mAb N100 against Ig domain 3 (D) young RGC axons in fascicles fail to adhere tightly to each other. The distance between neighboring axons is increased compared to controls (F). (E) mAb N518 against domain 2 does not interfere with tight fasciculation, but causes pathfinding errors of young RGC axons (arrow). C–F are from the temporal retina, oriented with the retinal margin to the right, and the optic disk to the left. Bars, B, 300 μm; C–F, 100 μm.
Mentions: After injections of either mAb N850 or mAb N100 (requiring the presence of Ig domains 1 and 3, respectively), the pattern of peripherocentrally oriented fascicles was preserved (Fig. 3, A and B) but the tight adherence of young axons within their fascicles was disturbed. The association of axons in loose bundles is illustrated in Fig. 3, C and D, and compared to the tighter fascicles in normal control (Fig. 3 F) and mAb N518 (Fig. 3 E) injected retinae. The defasciculation effect was most pronounced in the temporal retina and occurred in 8 out of 10 retinae after mAb N850 injections. Three retinae showed occasional (6–10) misoriented axon fascicles in the dorsal half of the retina, and two retinae appeared entirely normal.

Bottom Line: Repeated intraocular injections of a mAb against Ig domain 2 disturb the disk-directed growth: axons grow in aberrant routes and fail to reach the optic disk, but remain fasciculated. mAbs against Ig domains 1 and 3 disturb the formation of tight fascicles. mAb against Ig domain 2 significantly increases the incidence of growth cone departure from the disk-oriented fascicle track, while mAbs against Ig domains 1 and 3 do not.This was demonstrated by time-lapse videorecording of labeled growth cones.Thus, Ig domain 2 of neurolin is apparently essential for growth cone guidance towards the disk, presumably by being part of a receptor (or complex) for an axon guidance component.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Konstanz, D-78457 Konstanz, Germany.

ABSTRACT
The optic disk-directed growth of retinal ganglion cell axons is markedly disturbed in the presence of polyclonal antineurolin antibodies, which mildly affect fasciculation (Ott, H., M. Bastmeyer, and C.A.O. Stuermer, 1998. J. Neurosci. 18:3363-3372). New monoclonal antibodies (mAbs) against goldfish neurolin, an immunoglobulin (Ig) superfamily cell adhesion/recognition molecule with five Ig domains, were generated to assign function (guidance versus fasciculation) to specific Ig domains. By their ability or failure to recognize Chinese hamster ovary cells expressing recombinant neurolin with deletions of defined Ig domains, mAbs were identified as being directed against Ig domains 1, 2, or 3, respectively. Repeated intraocular injections of a mAb against Ig domain 2 disturb the disk-directed growth: axons grow in aberrant routes and fail to reach the optic disk, but remain fasciculated. mAbs against Ig domains 1 and 3 disturb the formation of tight fascicles. mAb against Ig domain 2 significantly increases the incidence of growth cone departure from the disk-oriented fascicle track, while mAbs against Ig domains 1 and 3 do not. This was demonstrated by time-lapse videorecording of labeled growth cones. Thus, Ig domain 2 of neurolin is apparently essential for growth cone guidance towards the disk, presumably by being part of a receptor (or complex) for an axon guidance component.

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Related in: MedlinePlus