Sialic acid content and growth control of mouse cells transformed by a temperature-sensitive mutant of SV40

The sialic acid content of mouse cells transformed by a temperature-sensitive mutants (ts-mutant) of Simian virus 40 (SV40) was measured, and proved to be derived from changes in the sialic acid content in the plasma membrane which resulted from changes in the microsomal sialytransferase activity. Plasma membrane glycoproteins of ts-mutant transformed cells showed significantly different patterns on electrofocusing, but when treated with neuraminidase, differences of elution patterns were extinguished. It was concluded that there was a positive correlation between sialic acid content and loss of contact inhibition in the cell line examined.