Rosenwald A G, Krag S S
Department of Biochemistry, Johns Hopkins School of Hygiene and Public Health, Baltimore, MD 21205.
J Lipid Res. 1990 Mar;31(3):523-33.
Lec9 Chinese hamster ovary cells were found previously to be defective in the synthesis of N-linked glycans. This appeared to be the result of a defect in the synthesis of oligosaccharide lipid and lipid phosphate (Rosenwald, Stanley, and Krag. 1989. Mol. Cell. Biol. 9: 914-924). In this study we analyzed the steady state levels of long-chain polyisoprenyl lipids in Lec9 cells. We found that Lec9 cells are defective in the synthesis of dolichol. They accumulated a presumed precursor to dolichol, cis-a-unsaturated polyprenol and used this lipid in the synthesis of oligosaccharide lipid. Chain lengths of the activated polyprenols in Lec9 were the same lengths as dolichols in parental cells. Lec9 cells had increased levels of monosaccharylphosphoryl lipid and decreased levels of oligosaccharylpyrophosphoryl lipid compared to parental cells. The defect in Lec9 cells was specific for dolichol synthesis, since other aspects of [3H]mevalonate metabolism in Lec9 cells were the same as in parental cells. We hypothesize that Lec9 cells are defective in polyprenol reductase activity.
之前发现Lec9中国仓鼠卵巢细胞在N-连接聚糖的合成方面存在缺陷。这似乎是由于寡糖脂和脂磷酸合成缺陷导致的（罗森瓦尔德、斯坦利和克拉格，1989年，《分子细胞生物学》9: 914 - 924）。在本研究中，我们分析了Lec9细胞中长链聚异戊二烯脂类的稳态水平。我们发现Lec9细胞在多萜醇的合成方面存在缺陷。它们积累了一种推测为多萜醇前体的顺式α-不饱和聚戊烯醇，并将这种脂类用于寡糖脂的合成。Lec9中活化聚戊烯醇的链长与亲代细胞中多萜醇的链长相同。与亲代细胞相比，Lec9细胞中单糖基磷酸脂水平升高，寡糖基焦磷酸脂水平降低。Lec9细胞中的缺陷是多萜醇合成特有的，因为Lec9细胞中[3H]甲羟戊酸代谢的其他方面与亲代细胞相同。我们推测Lec9细胞在聚戊烯醇还原酶活性方面存在缺陷。
