Isolation and characterization of rat schwannoma neurite-promoting factor: evidence that the factor contains laminin

摘要: Rat RN22 schwannoma cells in vitro release into their growth medium a macromolecular factor that, when bound to polyornithine-coated culture substrata, will stimulate neuritic regeneration from axotomized peripheral and central neurons. During the purification of this factor, neurite-promoting activity co-purifies with laminin immunoreactivity as measured by an enzyme-linked immunoadsorbent assay. The purified has per milligram protein similar that rat yolk sac tumor laminin. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions, exhibits major band at 200 kilodaltons (kD) two minor ones about 130 35 kD. 200-kD comigrates SDS- PAGE non-reducing both exhibit 900-kD range migrating slightly faster than one. (reducing conditions) (non-reducing bands are stained immunoblotting antisera raised against human partially preparation factor. On immunoblots 400-kD (a not seen preparation) also stains all three antisera. When antibodies each immobilized on A-agarose beads, beads completely remove solution neurite- promoting activities Antibodies fail block but totally In contrast, By rotary shadowing electron microscopy cross-shaped images identical those previously reported for mouse addition, contains resembling proteoglycans.