Project: Research project

Project Details


In order to investigate structure/function relationships of animal cell
carbohydrates, as series of glycosylation mutants of Chinese hamster ovary
(CHO) cells have been isolated. All of the mutants exhibit altered
carbohydrate biosynthesis and express new carbohydrate structures at the
cell surface. Twenty-five distinct phenotypes have been identified and
classified into seven dominant types and fourteen recessive complementation
groups. They have been used by many laboratories to study the roles of
carbohydrate moieties in the biosynthesis, compartmentalization and
functions of endogeneous or introduced glycoproteins. Recent studies in
this laboratory have shown that the altered carbohydrates synthesized by
Lec9 CHO mutants correlate directly with their reduced tumorigenicity in
nude mice.

The CHO glycosylation mutants provide an avenue to the isolation of
glycosylation genes and the determination of mechanisms that control their
expression. It is proposed to isolate new glycosylation mutants and
revertants using lectins as selective agents so that all the genes involved
in carbohydrate biosynthesis are identified. Studies on molecular
mechanisms that regulate glycosylation gene expression will focus on the
three dominant mutants, LEC10, LEC11 and LEC12. Their phenotypes appear to
be the result of gene activation since each of them expresses a novel
glycosyltransferase activity not detected in parental CHO. The abilities
of reagents that cause mutations and epigenetic changes such as
hypomethylation to alter the rates of appearance of these mutants and their
revertants will be examined. Co-transfection of genomic DNA with a plasmid
carrying a dominant selectable marker will be used to isolate the genes and
their expression will be compared in parental and mutant cells. These
studies should reveal mechanisms that regulate glycosylation gene
expression in CHO cells and provide probes to investigate the changes in
carbohydrate synthesis that occur during development, differentiation and
oncogenic transformation.
Effective start/end date1/1/902/29/00


  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute
  • National Cancer Institute


  • Genetics
  • Molecular Biology
  • Cancer Research


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