Location of procollagen in chick corneal and tendon fibroblasts with ferritin-conjugated antibodies

Three distinct antiprocollagen preparations were characterized and used in immunocytochemical staining of chick embryo corneal and tendon cells. The several ferritin-conjugated antibody preparations permitted similar location of procollagen in the cisternae of the rough endoplasmic reticulum and in Golgi elements in both cell types. The ability to demonstrate and interpret specific ferritin staining was dependent on the extent of membrane breakage in each of those organelles, coupled with adequate retention of cell morphology. Corneal fibroblasts appeared to suffer more extensive intracellular membrane damage under controlled conditions of homogenization than tendon fibroblasts, facilitating the identification of procollagen in Golgi vacuoles of these cells. None of the labeled material appeared to by cytoplasmic in origin since ferritin was observed in the cytoplasm only in the vicinity of Golgi elements that were extensively broken. This study extends previous immunological evidence for the presence of procollagen in the Golgi complex and calls attention to the problems to be encountered in locating the antigen in small Golgi vesicles and lamellae.