Role of Sialic Acid and Sialyltransferase

Following treatment of the fucose-labeled glycopeptides derived from the surfaces of RSV-BHK cells with neuraminidase, the radioactive products appeared similar to glycopeptides from normal cells (Warren et al., 19726). These results suggested that increased sialic acid content may account for the higher molecular weight of the glycopeptides from transformed cells. When sialyltransferase activity was as- 

Sialyltransferase activities in normal and virally transformed mouse 3T3 cells have also been measured with specific endogenous acceptors (Bosmann, 1972a). The acceptors were prepared by incubating the intact cells with neuraminidase and then trypsin. The desialylated material released from the cells was used to measure sialyltransferase activity in crude detergent extracts of the cells. Cells transformed by MSV, RSV, or Py had more acceptor and transferase activity than normal 3T3 cells. Surface sialyltransferase activity as measured by the ability of intact cells to transfer sialic acid- C from CMP-NANA- C to undefined surface acceptors was also higher in the transformed lines (Bosmann, 1972 ). 

The block in ganglioside biosynthesis observed in a variety of SV40- and Py-transformed mouse cells suggests that the alteration is related to some function common to both of these DNA tumor viruses (Mora et al., 1971). Several considerations have to be explored. 

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