Calpain processing of brain microtubules from the Atlantic Cod,Gadus morhua

Viral infection of cultured cells with transforming viruses causes an increase in cell-surface N-linked 1-6 (GlcNAc1-6Man) branching of complex-type oligosaccharides. Similar observations have been made after transfection of cells with activated oncogenes, which is associated with an induction of tumorigenic and metastatic properties. In this study, the effects of transfection of both activated and proto-Ha-ras oncogenes into NIH3T3 cells were analyzed. The results showed that, in comparison with NIH3T3 cells, bothras transfectants have increased sensitivity to the cytotoxic action of L-PHA. An increase in 1-6 branching and an increased level of N-acetylglucosaminyltransferase V (GlcNAc-T V), the enzyme which initiates the 1-6 branching were also observed. The levels of GlcNAc-T I and 1-4 Gal-T remained unchanged in activated Ha-ras transfected NIH3T3 cells. These data suggest that a specific induction of GlcNAc-T V occurs after transfection with either the proto- or activated Ha-ras oncogenes, which is responsible for the increased 1-6 branching previously observed. (Mol Cell Biochem122: 85–92, 1993)Abbreviations Asn Asparagine - BHK Baby Hamster Kidney (cells) - 1-4 Gal-T or Gal-T 1-4 Galactosyltransferase - BSL-II Banderia Simplifolia Lectin II - CHO Chinese Hamster Ovary (cells) - ConA Concanavalin A - D-MEM Dulbecco's Modified Eagle's Medium - E-PHA Erythroagglutinin of Phytohemagglutinin - Fuc Fucose - Gn or GlcNAc N-acetylglucosamine - GlcNAc-T I N-acetylglucosaminyltransferase I - LCA Lens Culinaris Agglutinin - L-PHA Leukoagglutinin of Phytohemagglutinin - M or Man Mannose - PBS Phosphate-Buffered Saline - PL Pea Lectin - RIC Ricin - SDS-PAGE Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis - UDP-Gal Uridine-Diphosphate-Galactose - UDP-Gn Uridine-Diphosphate-N-acetylglucosamine - WGA Wheat Germ Agglutinin