Alterations in surface glycoproteins and level of sialyltransferase of cells transformed by a temperature-sensitive mutant of simian virus 40.

Abstract

Mouse cells [900-2K-34] transformed by a temperature-sensitive mutant of SV-40 belonging to complementation group A lost their ability to regulate cell growth when grown at the permissive temperature (35.degree. C) but showed the low saturation density of cell growth at the restrictive temperature (39.5.degree. C) that is characteristic of normal cells in vitro. Biochemical analysis of the membranes of cells grown under the restrictive and the permissive conditions demonstrated no qualitative temperature-dependent differences in neutral glycolipids or in acidic glycolipids of the cells. Plasma membrane glycoproteins labeled with radioactive glucosamine showed significantly different patterns on polyacrylamide gel electrophoresis and electrofocusing. When the levels of glycoprotein glycosyltransferases of the cells were examined, the level of sialyltransferase (CMP-N-acetylneuraminate:D-galactosyl-glycoprotein N-acetylneuraminyltransferase, EC 2.4.99.1) of the cells grown at the restrictive temperature was low compared with that of cells grown at the permissive temperature. The level of sialyltransferase may be under the control of the gene A function of SV-40 and consequently is related to alterations in the cell surface glycoproteins.