Human genetics : possibilities and realities.

  • Symposium on Genetics and Human Biology: Possibilities and Realities (1978 : London, England)
Date:
1979
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Human genetics : possibilities and realities. Source: Wellcome Collection.

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    332 DISCUSSION for revertants. In some of the cell lines, no revertants have been reported. Brenner: A likely explanation is that there are multiple isozymes of glucose transport which happen to have different glycosylation patterns and that one particular one has been switched on in tumour cells. I cannot see any other way of looking at the results as long as you assure us that the change in glycosylation is not global. It could depend in some way on the amino acid sequence of the protein itself. Henry Harris: I would think it does. Milstein: Not necessarily. It could be the ratio of the different glycosylating enzymes. Brenner: But then I think you would find that many proteins would be altered. Perhaps this is a special isozyme with insulin resistance or other physiological properties. Perhaps it is needed by the cell for malignant growth in animals. Henry Harris: On some of the tumours one certainly gets what people call microheterogeneity in that region. You get multiple peaks, and there is evidence that they may be due to differences in the polysaccharide components of the proteins. Milstein: In some cases they are. Henry Harris: Yes, but in this case we don't know. We do, however, have evidence that these multiple peaks are functionally homologous. Harry Harris: Have you ever looked at two-dimensional gels after treating the preparations with neuraminidase? You are talking about a low isoelectric point and if there are a lot of siahc acids, these could largely determine the isoelectric point. If you remove them, you might see differences. Henry Harris: Mike Bramwell has tried neuraminidase, but not a really pure neuraminidase. When cells are treated with commercial neuraminidase you lose a great deal of the material that binds wheat-germ agglutinin on the cell surface. But you do not convert the high wheat-germ agglutinin binding in the 100 ООО molecular mass protein to a high concanavalin-binding configuration. So the difference between malignant and non-malignant cells is not merely due to terminal sialic acid. References Boyd, Y. & Harris, H. (1973) Correction of genetic defects in mammalian cells by the input of small amounts of foreign genetic material. J. Cell Sci. 13, 841-861 Goss, S.J. & Harris, H. (1977ö) Gene transfer by means of cell fusion. I. Statistical mapping of the human X-chromosome by analysis of radiation-induced gene segregation. J. Cell Sci. 25, 17-37