biostudies-literatureKentache TUniversité Catholique de LouvainBaillet Latour FundMizutani Foundation for GlycoscienceEuropean Research CouncilKU Leuven Research CouncilFondation Médicale Reine ElisabethFrench National Research AgencyNIHFund for Scientific ResearchResearch Foundation Flanders107875https://www.ebi.ac.uk/biostudies/studies/S-EPMC11607601biostudies-literatureUnknown300(12)Glycosylation-deficient Chinese hamster ovary cell lines have been instrumental in the discovery of N-glycosylation machinery. Yet, the molecular causes of the glycosylation defects in the Lec5 and Lec9 mutants have been elusive, even though for both cell lines a defect in dolichol formation from polyprenol was previously established. We recently found that dolichol synthesis from polyprenol occurs in three steps consisting of the conversion of polyprenol to polyprenal by DHRSX, the reduction of polyprenal to dolichal by SRD5A3, and the reduction of dolichal to dolichol, again by DHRSX. This led us to investigate defective dolichol synthesis in Lec5 and Lec9 cells. Both cell lines showed increased levels of polyprenol and its derivatives, concomitant with decreased levels of dolichol and dThe Journal of biological chemistryAbsence of the dolichol synthesis gene DHRSX leads to N-glycosylation defects in Lec5 and Lec9 Chinese hamster ovary cells.PMC11607601771704Contessa JNBommer GTWilson MPCaligiore FSchulz CGraff JPieters EStanley PSouche EKentache TAlthoff CRMatthijs GVan Schaftingen EFoulquier FfalseAbsence of the dolichol synthesis gene DHRSX leads to N-glycosylation defects in Lec5 and Lec9 Chinese hamster ovary cells.Glycosylation-deficient Chinese hamster ovary cell lines have been instrumental in the discovery of N-glycosylation machinery. Yet, the molecular causes of the glycosylation defects in the Lec5 and Lec9 mutants have been elusive, even though for both cell lines a defect in dolichol formation from polyprenol was previously established. We recently found that dolichol synthesis from polyprenol occurs in three steps consisting of the conversion of polyprenol to polyprenal by DHRSX, the reduction of polyprenal to dolichal by SRD5A3, and the reduction of dolichal to dolichol, again by DHRSX. This led us to investigate defective dolichol synthesis in Lec5 and Lec9 cells. Both cell lines showed increased levels of polyprenol and its derivatives, concomitant with decreased levels of dolichol and d2024-01-01T00:00:00Z2024 Dec2026-06-01T07:09:46.477Z2025-04-04T01:23:59.896ZS-EPMC116076013939580210.1016/j.jbc.2024.107875