A
ganglioside GM1-specific alpha 1-->2fucosyltransferase is induced during the early stages of chemical
carcinogenesis with N-2-acetylaminofluorene (AAF) in rat liver hepatocytes. The induction of this
enzyme gives rise to the expression of a
fucose-containing
ganglioside with the same determinant structure as
blood group B on a
GM1 ganglioside core. Fucoganglioside synthesis is not found in normal rat liver but is elevated in premalignant liver and is often highly expressed in derived rat
hepatoma cell lines. Based upon the consensus sequence from portions of previously cloned human, rabbit, and rat alpha 1-->2fucosyltransferase
enzymes, primers were designed which were used in RT-PCR experiments with rat
hepatoma H35 cell total
RNA to generate cDNAs encoding the extracellular, catalytic domain of the H35 cell alpha 1-->2fucosyltransferase. Sequencing of these PCR fragments showed them to encode a novel
enzyme with high homology to other cloned
enzymes, particularly secretor alpha 1-->2fucosyltransferases. The derived sequence indicated that the 3' portion of the gene was virtually identical to the alpha 1-->2fucosyltransferase B (FTB) fragment reported earlier in rat PROb
colon-adenocarcinoma cells (J-P. Piau et al. Biochem. J. 300, 623-626, 1994). A PCR product corresponding to the H35 cell alpha 1-->2fucosyltransferase was obtained from total
RNA isolated from F344 rat liver after 0.03% N-2-acetylaminofluorene administration. No PCR product was obtained from total
RNA isolated from normal F344 liver using PCR primers for the H35 cell alpha 1-->2fucosyltransferase. The H35 cell alpha 1-->2fucosyltransferase was expressed in the pPROTA vector and the derived fusion
protein demonstrated the ability to transfer
fucose to
ganglioside GM1 but not to the neolacto-series acceptor nLcOse4Cer.