Fig. 8. TN-R cooperates with immobilized brevican and contactin 1 on the tectal cell surface to induce neurite outgrowth. (A-F) Petriperm dishes were coated with brevican overnight and blocked, and tectal cells were cultivated for 40 hours in the (A) absence or (B,D-F) presence of TN-R (10 µg/ml) together with (D) Fab fragments of pAb against contactin 1 (500 µg/ml), (E) Fab fragments of pAb against TN-R FNIII domains 4-A (500 µg/ml) or (F) aggrecan (20 µg/ml). Bar, 50 µm. Cell attachment and neurite outgrowth on a brevican substrate are induced in the presence of TN-R and depend on the simultaneous interaction of TN-R with immobilized brevican and contactin 1 on the tectal cell surface. (C) Schematic illustration of the proposed sandwich that mediates neurite outgrowth.