Cell mutants oligosaccharides

Still another approach to solving the problem of detecting intenne-diates in the assembly of the lipid-linked oligosaccharide comes from the use of cell mutants having defects in the synthesis of an essential intermediate. This approach has proved productive (see later). 

There are many glycosylation mutants of cultured mammalian cells and yeast. They have been selected as rare survivors of treatments that kill cells expressing a particular carbohydrate or glycoprotein at the cell surface. For example, plants produce a variety of proteins, called lectins, which bind to cell surface oligosaccharides. Lectins are toxic to mammalian cells. They can be used to select for mutants that no longer bind the lectin because they lack a particular carbohydrate at the cell surface. Such glycosylation mutants have low amounts of glycoproteins that require carbohydrates for stable expression. 

Dennis, J. W., Laferte, S., Fukuda, M., Dell, A., and Carver, J. P., 1986, Asn-linked oligosaccharides in lectin-resistant tumor-cell mutants with varying metastatic potential, Eur. J. Biochem. 161 359-373. 

Numerous lectins have been purified and are commercially available three plant lectins that have been widely used experimentally are listed in Table 47-7. Among many uses, lectins have been employed to purify specific glycoproteins, as tools for probing the glycoprotein profiles of cell surfaces, and as reagents for generating mutant cells deficient in certain enzymes involved in the biosynthesis of oligosaccharide chains. 

Other mutants of Chinese-hamster ovary-cells having decreased amounts of lipid-linked oligosaccharides are known, although they are less well characterized. G-Protein of vesicular stomatitis virus grown in one of these mutants appeared to contain fewer, but full-sized rather than truncated, oligosaccharide side-chains. There may be insufficient amounts of oligosaccharide precursor available for transfer to nascent glycoproteins.172... 

O-Linked Oligosaccharides Are Responsible for Different Blood Group Types Specific Inhibitors and Mutants Are Used to Explore the Roles of Glycoprotein Carbohydrates Bacterial Cell Wall Synthesis... 

Dennis, J. W., Carver, J. P. and Schachter, H. (1984). Asparagine-linked oligosaccharides in murine tumor cells comparison of a WGA-resistant (WGAr) nonmetastatic mutant and a related WGA-sensitive (WGAs) metastatic line. J. Cell Biol. 99, 1034-1044. 

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