Details

Autor(en) / Beteiligte

• Bry, Lynn
• Falk, Per G.
• Gordon, Jeffrey I.

Titel

Genetic Engineering of Carbohydrate Biosynthetic Pathways in Transgenic Mice Demonstrates Cell Cycle-Associated Regulation of Glycoconjugate Production in Small Intestinal Epithelial Cells

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 1996-02, Vol.93 (3), p.1161-1166

Ort / Verlag

United States: National Academy of Sciences of the United States of America

Erscheinungsjahr

1996

Quelle

MEDLINE

Beschreibungen/Notizen

• Proliferation, migration-associated differentiation, and cell death occur continuously and in a spatially well-organized fashion along the crypt-villus axis of the mouse small intestine, making it an attractive system for studying how these processes are regulated and interrelated. A pathway for producing glycoconjugates was engineered in adult FVB/N transgenic mice by expressing a human α 1,3/4-fucosyltransferase (α 1,3/4-FT; EC 2.4.1.65) along the length of this crypt-villus axis. The α 1,3/4-FT can use lacto-N-tetraose or lacto-neo-N-tetraose core chains to generate Lewis (Le) blood group antigens Lea or Lex, respectively, and H type 1 or H type 2 core chains to produce Leb and Ley. Single- and multilabel immunohistochemical studies revealed that expression of the α 1,3/4-FT results in production of Lea and Leb antigens in both undifferentiated proliferating crypt cells and in differentiated postmitotic villus-associated epithelial cells. In contrast, Lex antigens were restricted to crypt cells. Villus enterocytes can be induced to reenter the cell cycle by expression of simian virus 40 tumor antigen under the control of a promoter that only functions in differentiated members of this lineage. Bitransgenic animals, generated from a cross of FVB/N α 1,3/4-FT with FVB/N simian virus 40 tumor antigen mice, expand the range of Lex expression to include villus-associated enterocytes that have reentered the cell cycle. Thus, the fucosylations unveil a proliferation-dependent switch in oligosaccharide production, as defined by a monoclonal antibody specific for the Lex epitope. These findings show that genetic engineering of oligosaccharide biosynthetic pathways can be used to define markers for entry into, or progression through, the cell cycle and to identify changes in endogenous carbohydrate metabolism that occur when proliferative status is altered in a manner that is not deleterious to the system under study.