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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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Representative frames from time-lapse sequences  showing growing RGC axons in a noninjected control retina, and  after injections of mAb N518. The optic disk is to the right. (A  and B) DiO-labeled growth cones (arrows) elongate towards the  optic disk in association with other labeled axons of the same fascicle (control retina). (C–F) DiO-labeled growth cones (arrows)  in mAb N518-injected retinae depart from their fascicle of origin  (bright band) either obliquely (C and F), or at right angles (E),  and turn away from the optic disk (D). Bar, 20 μm.
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Figure 6: Representative frames from time-lapse sequences showing growing RGC axons in a noninjected control retina, and after injections of mAb N518. The optic disk is to the right. (A and B) DiO-labeled growth cones (arrows) elongate towards the optic disk in association with other labeled axons of the same fascicle (control retina). (C–F) DiO-labeled growth cones (arrows) in mAb N518-injected retinae depart from their fascicle of origin (bright band) either obliquely (C and F), or at right angles (E), and turn away from the optic disk (D). Bar, 20 μm.

Mentions: To quantitatively assess axonal pathfinding errors caused by each of the three mAbs and neurolin Fabs, we isolated retinae after two intraocular injections of either mAb N850, N518, N100, or neurolin Fabs, applied DiO to the retinal margin, and observed the DiO-labeled growth cones by videomicroscopic recordings for 2–6 h. We determined how many growth cones deviate for >10° from the fascicle pathway for each antibody injected and in buffer-injected and in noninjected retinae. Growth cones traveling along their fascicle and examples of errant growth cones in mAb N518-treated retinae are presented in Fig. 6. Growth cones depart from their fascicle of origin obliquely (Fig. 6, C and F), or at right angles (Fig. 6 E), cross other fascicles (Fig. 6 D), and show signs of growth in the wrong direction, i.e., away from the optic disk (Fig. 6 D).


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)

Representative frames from time-lapse sequences  showing growing RGC axons in a noninjected control retina, and  after injections of mAb N518. The optic disk is to the right. (A  and B) DiO-labeled growth cones (arrows) elongate towards the  optic disk in association with other labeled axons of the same fascicle (control retina). (C–F) DiO-labeled growth cones (arrows)  in mAb N518-injected retinae depart from their fascicle of origin  (bright band) either obliquely (C and F), or at right angles (E),  and turn away from the optic disk (D). Bar, 20 μm.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132892&req=5

Figure 6: Representative frames from time-lapse sequences showing growing RGC axons in a noninjected control retina, and after injections of mAb N518. The optic disk is to the right. (A and B) DiO-labeled growth cones (arrows) elongate towards the optic disk in association with other labeled axons of the same fascicle (control retina). (C–F) DiO-labeled growth cones (arrows) in mAb N518-injected retinae depart from their fascicle of origin (bright band) either obliquely (C and F), or at right angles (E), and turn away from the optic disk (D). Bar, 20 μm.
Mentions: To quantitatively assess axonal pathfinding errors caused by each of the three mAbs and neurolin Fabs, we isolated retinae after two intraocular injections of either mAb N850, N518, N100, or neurolin Fabs, applied DiO to the retinal margin, and observed the DiO-labeled growth cones by videomicroscopic recordings for 2–6 h. We determined how many growth cones deviate for >10° from the fascicle pathway for each antibody injected and in buffer-injected and in noninjected retinae. Growth cones traveling along their fascicle and examples of errant growth cones in mAb N518-treated retinae are presented in Fig. 6. Growth cones depart from their fascicle of origin obliquely (Fig. 6, C and F), or at right angles (Fig. 6 E), cross other fascicles (Fig. 6 D), and show signs of growth in the wrong direction, i.e., away from the optic disk (Fig. 6 D).

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.

Show MeSH
Related in: MedlinePlus