Immunofluorescent localization of protein synthesis components in mouse embryo fibroblasts

The distribution of initiation factor 2(eIF-2) and elongation factor 2(EF-2) in cultured mouse embryo fibroblasts was studied and compared with the distribution of ribosomes. We used immunofluorescence microscopy with monospecific antibodies to eIF-2, EF-2, and proteins S3a and S7 of the small ribosomal subunit. Ribosomes and factors eIF-2 and EF-2 were found mainly in the vicinity of the cell nucleus. This perinuclear zone coincides with the endoplasm - the central part of the cell containing numerous membraneous organelles and inclusions. Besides the perinuclear zone, small stained regions could be seen at the periphery of some cells. After treatment of the cells with Triton X-100 in a buffer conditions, that stabilizes the major cytoskeletal structures, some of the ribosomes, eIF-2, and EF-2 remained bound to the insoluble material. These components were found near the nucleus and some were located along the microfilament bundles.