GLYCOSYLATION DEFECTS OF LECTIN-RESISTANT TUMOR CELLS

Project: Research project

Project Details

Description

The aim is the in-depth biochemical characterization of several Chinese
hamster ovary (CHO) glycosylation mutants recently-isolated by this
laboratory. The mutants were selected for resistance to plant lectins and
exhibit properties typical of those that we have previously shown to arise
from altered carbohydrate biosynthesis. Genetic studies have shown that
each mutant type is novel and thus would be expected to express biochemical
defects previously undescribed in CHO cells.

The experimental approach is to define the structural carbohydrate change
expressed by each mutant type and, based on this knowledge, to assay for
the activity that might be responsible for the observed glycosylation
phenotype. The mutants to be studied with highest priority include four
dominant mutants (LEC14, LEC16, LEC17 and LEC 8) and four recessive mutants
(Lec9, Lec19, Lec20 and Lec21). The biochemical bases of dominance are of
interest to mechanisms by which cells may change their array of
carbohydrates in a single step. The characterization of Lec9 mutants is
important because they are the only mutant in our repertoire to exhibit
markedly-reduced tumorigenicity in the nude mouse.

Carbohydrates from the glycoproteins of animal viruses such as vesicular
stomatitis virus or from the cell surface will be radiolabeled and
structurally characterised by lectin-affinity and gel filtration
chromatography with the aid of specific glycosidases. Additional
structural information will be obtained from designated species by 1H-NMR
spectroscopy at 500 MHz. Once the structural changes expressed by a mutant
are known, assays for glycosyltransferases and other enzyme activities will
be developed to pinpoint the enzymic basis of each defect.
StatusFinished
Effective start/end date1/1/901/1/90

Funding

  • National Cancer Institute

ASJC

  • Oncology
  • Cancer Research

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