Deutscher S L, Nuwayhid N, Stanley P, Briles E I, Hirschberg C B
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.
来自Lec2 CHO糖基化突变体的高尔基体囊泡膜转运CMP - 唾液酸的速率仅为野生型CHO细胞囊泡的2%。这种缺陷是特异性的，因为来自Lec2细胞的囊泡转运UDP - N - 乙酰葡糖胺、3'-磷酸5'-磷酸腺苷硫酸酯和UDP - 半乳糖的速率与来自野生型细胞的囊泡相当。互补分析表明，Lec2突变体与具有相似表型的CHO突变体克隆1021属于同一遗传互补组。与野生型细胞相比，这两种突变体先前均已显示糖蛋白和神经节苷脂的唾液酸化减少了90%。然而，1021细胞似乎具有正常水平的CMP - 唾液酸、唾液酸转移酶活性和唾液酸化的内源性受体。Lec2和1021细胞的主要缺陷似乎是它们无法将CMP - 唾液酸转运穿过高尔基体囊泡膜。
