Binding of dextran sulfate by virus-transformed cells, with reference to altered growth behavior by its treatment

Binding of ³H-labeled dextran sulfate on transformed and untransformed cells was studied in relation to the altered growth of transformed cells by this treatment. 3T3 and SV3T3 cells, and the isolated cells (SV3T3-R5) insensitive to dextran sulfate treatment were used. The rate of binding of ³H-dextran sulfate on SV3T3 cells was dose-dependent when examined by the liquid scintillation method. It was revealed in autoradiographic analysis that there was no difference in the binding capacity of ³H-dextran sulfate among 3T3, SV3T3, and SV3T3-R5 cells. The rate of binding proceeded linearly during the first 10 hr and then tended to decline. Thin sections (0.3-0.5 μm) of SV3T3 cells were autoradiographed to examine the site of localization of ³H-dextran sulfate. Depending on the incubation time with the cells, ³H-dextran sulfate was located first on the cell surface and then in the cytoplasm when incubated further. Finally, silver grains were detected even in the nucleus of SV3T3 cells. This process of localization was similar in 3T3 cells. Binding of ³H-dextran sulfate on SV3T3 cells was independent of the presence of calf serum in the medium.