Blocks in Ganglioside Synthesis in Transformed Hamster Cells and Their Revertants

Hamster cells transformed by polyoma virus or by treatment with the chemical carcinogen dimethylnitrosamine and revertants from these transformed cells were examined for UDP-N-acetylgalactosamine:hematoside N-acetylgalactosaminyltransferase activity and for their types of gangliosides. Compared to normal cells, both the transformed and revertant cells showed 3 to 12% of the enzyme activity and a simplification of the ganglioside pattern. The presence of similar blocks in glycosyltransferase activity and ganglioside synthesis in these transformed cells and their revertants indicates that these blocks were not associated with the regulation of cell growth, but may be due to a common genetic change in transformed cells and their revertants that is not found in normal cells.