Transfection with fragments of the adenovirus 12 gene induces tumorigenicity-associated alteration of N-linked sugar chains in rat cells

Abstract

N-linked sugar chains of rat 3Y1 cells and their poorly tumorigenic (E1Y cells) and highly tumorigenic (CY1 cells) transformants carrying various adenovirus 12 gene fragments were quantitatively released as oligosaccharides from their membrane preparations by hydrazinolysis. After being fractionated by a series of immobilized lectin column chromatography, structures of oligosaccharides in each fraction were studied by sequential glycosidase digestion in combination with methylation analysis. All cells contain bi-, tri-, and tetraantennary complex-type oligosaccharides as well as high mannose-type oligosaccharides in different molar ratio. Expression of 2,4-branched triantennary oligosaccharides increased in both transformed cells. However, their contents were rather higher in poorly tumorigenic E1Y cells than in highly tumorigenic CY1 cells. In contrast, the increase of 2,6-branched triantennary and tetraantennary oligosaccharides was positively correlated to the tumorigenic potential of the transformed cells. The data indicate that glycosylation of cellular proteins is differently affected by the expression of specific regions of the adenovirus genome, and the combined action of E1 and E4 gene products is important for the expression of the GlcNAcβ1→ 6Man group associated with tumorigenicity of the cells.