Translocation across Golgi vesicle membranes: a CHO glycosylation mutant deficient in CMP-sialic acid transport

Cell. 1984 Dec;39(2 Pt 1):295-9. doi: 10.1016/0092-8674(84)90007-2.


Golgi vesicle membranes from the Lec2 CHO glycosylation mutant translocate CMP-sialic acid at only 2% the rate of vesicles from wild-type CHO cells. The deficiency is specific, because vesicles from Lec2 cells can translocate UDP-N-acetylglucosamine, adenosine 3'-phosphate 5'-phosphosulfate, and UDP-galactose at rates comparable to those of vesicles from wild-type cells. Complementation analyses show that Lec2 mutants belong to the same genetic complementation group as clone 1021, a CHO mutant of similar phenotype. Both mutants have previously been shown to have a 90% reduction in the sialylation of glycoproteins and gangliosides compared with wild-type cells. However, 1021 cells appear to have normal levels of CMP-sialic acid, sialyltransferase activity, and endogenous acceptors for sialylation. It seems likely that the primary defect in Lec2 and 1021 cells is their inability to translocate CMP-sialic acid across Golgi vesicle membranes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Transport
  • Cell Fractionation
  • Cell Line
  • Cricetinae
  • Cricetulus
  • Cytidine Monophosphate N-Acetylneuraminic Acid / metabolism
  • Female
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • Intracellular Membranes / metabolism*
  • Kinetics
  • Mutation
  • Ovary


  • Cytidine Monophosphate N-Acetylneuraminic Acid