title: A lens fibre differentiation factor from calf neural retina.
abstract: During growth of the eye lens, epithelial cells differentiate into fibre cells under the influence of neural retina. The fibre differentiation factor (FDF) was partially characterized from calf retina-conditioned medium, using lens epithelial explants from young rats, to provide a bioassay for differentiation. FDF was associated with large-protein aggregates, the smallest of which eluted at approximately 500-600 kD on Sephacryl S-300 columns and migrated as a single protein band near 600 kD on gradient gels. This protein resolved into nine major peptides on SDS-polyacrylamide gels, ranging between 23 and 27 kD. Eight of these peptides were present oa four doublets, but did not appear to contain specific carbohydrate residues. The approximately 500-600 kD complex could be slightly disrupted by trypsin or heat treatment to release a less stable 90 kD component. Fractionation of FDF invariably led to loss of activity, possibly due to gradual dissociation into less active and/or less stable components. A working hypothesis suggested by these findings is that FDF is associated with a small group of peptides, each contributing an essential function to the process of fibre differentiation.
mesh_terms: D000818:Animals; D002417:Cattle; D002454:Cell Differentiation; D002478:Cells, Cultured; D003459:Crystallins / Q000096:biosynthesis; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells; D005136:Eye Proteins / Q000302:isolation & purification* / Q000502:physiology; D007908:Lens, Crystalline / Q000166:cytology*; D008970:Molecular Weight; D009924:Organ Culture Techniques; D012160:Retina / Q000032:analysis*; D012165:Retinal Ganglion Cells / Q000032:analysis*
chemical_list: D003459:Crystallins; D003470:Culture Media; D005136:Eye Proteins