Sialic Acid and Sialyltransferase Activity in Transformed Cells

Sialic Acid and Sialyltransferase Activity in Transformed Cells 

Total sialic acid content was found to be lower in several SV40-transformed clones of Swiss 3T3 mouse cells (Ohta et aL, 1968). The plasma membrane as well as other membrane fractions of similar cell lines had reduced amounts of sialic acid (Wu et aL, 1969). Isolated plasma membranes from Py-BHK cells had 60% less sialic acid than membranes from normal BHK cells (Makita and Seyama, 1971). These changes appear to be associated with reduced sialyltransferase activities in the transformed cells. Grimes (1970) determined the levels of sialic acid and sialyltransferase activity in normal and SV40-transformed Swiss and Balb 3T3 mouse cells. There was a close correlation between sialic acid content and sialyltransferase activity in each cell line even though enzyme levels were measured with exogenous acceptors such as desialylated fetuin or bovine submaxillary mucin. This correlation has been extended to a number of other cell lines (Grimes, 1973). 

There is also an inverse correlation between the sialic content and saturation density of various Swiss 3T3 lines (Culp et aL, 1971). Untransformed and flat revertant cell lines had the highest content of 

Glucosamine-labeled plasma membranes obtained from normal, SV40-, and Py-transformed Swiss 3T3 cells have been compared by coelectrophoresis on SDS-polyacrylamide gels (Sheinin and Onodera, 

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A. Sialic Acid and Sialyltransferase Activity in Transformed Cells... 

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