Aggregation properties of chondrocytes infected with a temperature-sensitive mutant of Rous sarcoma virus

Aggregation capacity of chicken embryo chondrocytes decreases when transformed by Rous sarcoma viruses. Cell-to-cell aggregation capacity of chondrocytes infected with a T class temperature-sensitive mutant (tsNY68) (with the temperature-sensitive lesion at the src gene) of Rous sarcoma virus is dependent upon the temperature at which these cells are grown. When grown at the permissive temperature (36 degrees C), where the transforming gene is expressed, aggregation capacity was lower than normal while infected cells grown at the non-permissive temperature (41.5 degrees C) had similar capacity to aggregate to that of normal chondrocytes. However, after a prolonged period of culture (10 days), chondrocytes transformed by wild type SR-RSV regained the normal level of aggregation capacity. Cells transformed by tsNY68 and incubated at the permissive temperature for 10 days also regained the normal level of aggregation capacity. It appears therefore that RSV-transformed chondrocytes first become less adhesive but during long-term cultivation they regain their property to aggregate. The decrease of aggregation capacity due to T class mutants of RSV at 36 degrees C is dependent on constant maintenance of protein synthesis because addition of cycloheximide restored the aggregation capacity even at the permissive temperature.