Compartmentation of the Golgi complex: brefeldin-A distinguishes trans- Golgi cisternae from the trans-Golgi network

Chinese hamster ovary (CHO) clone 13, clone 15B, and clone 1021 cells were originally obtained from Dr. S. Kornfeld by Dr. J. Rothman, who provided them to our laboratory. CHO clone 13 cells cannot translocate UDP-galactose into the Golgi and display an apparent defect in galactosyltransferase (6); CHO 15B cells lack GlcNAc transferase I activity (20) ; clone 1021 cells lack CMP-sialic acid translocase activity, and thus cannot add sialic acid to oligosaccbaride chains (6, 8) . CHO clone 15B and clone 1021 cell lines were grown as monolayers in c~MEM containing 7.5% fetal calf serum and antibiotics. CHO wild-type and clone 13 cells were grown in suspension culture in the same media.