Quantitative analysis of freeze fracture morphology of mouse embryo cells treated with retinoids and phorbol esters

Abstract

Phenotypic changes in C3H/10T mouse embryo fibroblast cells, induced by retinyl acetate (RAC) or 12-0-tetradecanoylphorbol-13-acetate (TPA) treatments, were studied by freeze fracture electron microscopy. TPA accelerates transformation while RAC suppresses transformation in these cells.Unfixed cells on glass substrates were rapidly frozen in liquid propane by the sandwich method. Freeze fracture was carried out at -120°C and vacuum better than 5x10-7torr in a Polaron unit equipped with a Perkin-Elmer Ultek ion pump and Cressi ngton electron guns. Intramembraneous particle (IMP) detection and quantitation was done using a Cambridge Instrument Quantimet 920 image analyzer with a macroviewer attachment.