Chinese hamster ovary cell mutants affecting cholesterol metabolism

Chang, Ta−Yuan; Hasan, Mazahir T.; Chin, Jean; Chang, Catherine C.Y.; Spillane, Diane M.

doi:10.1097/00041433-199704000-00003

Cited by 31 publications

(10 citation statements)

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“…The mature form of the SREBPs also activates genes encoding enzymes of fatty acid biosynthesis, including acetyl coenzyme A carboxylase, fatty acid synthase, and stearoyl coenzyme A desaturase-1 (for review see reference 1). CHO cells with defects in the action of the Site-2 protease are auxotrophic for sterols and unsaturated fatty acids (2,6).…”

Section: Introductionmentioning

confidence: 99%

Elevated levels of SREBP-2 and cholesterol synthesis in livers of mice homozygous for a targeted disruption of the SREBP-1 gene.

Shimano¹,

Shimomura²,

Hammer³

et al. 1997

J. Clin. Invest.

401

302

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The synthesis of cholesterol and its uptake from plasma LDL are regulated by two membrane-bound transcription factors, designated sterol regulatory element binding protein-1 and -2 (SREBP-1 and SREBP-2). Here, we used the technique of homologous recombination to generate mice with disruptions in the gene encoding the two isoforms of SREBP-1, termed SREBP-1a and SREBP-1c. Heterozygous gene-disrupted mice were phenotypically normal, but 50-85% of the homozygous ( Ϫ / Ϫ ) mice died in utero at embryonic day 11. The surviving Ϫ / Ϫ mice appeared normal at birth and throughout life. Their livers expressed no functional SREBP-1. There was a 1.5-fold upregulation of SREBP-2 at the level of mRNA and a two-to threefold increase in the amount of mature SREBP-2 in liver nuclei. Previous studies showed that SREBP-2 is much more potent than SREBP-1c, the predominant hepatic isoform of SREBP-1, in activating transcription of genes encoding enzymes of cholesterol synthesis. Consistent with this observation, the SREBP-1 Ϫ / Ϫ animals manifested elevated levels of mRNAs for 3-hydroxy-3-methylglutaryl coenzyme A synthase and reductase, farnesyl diphosphate synthase, and squalene synthase. Cholesterol synthesis, as measured by the incorporation of

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Section: Introductionmentioning

confidence: 99%

Elevated levels of SREBP-2 and cholesterol synthesis in livers of mice homozygous for a targeted disruption of the SREBP-1 gene.

Shimano¹,

Shimomura²,

Hammer³

et al. 1997

J. Clin. Invest.

401

302

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“…One of the most pronounced abnormalities in affected cells is the accumulation of free cholesterol derived from low density lipoproteins (LDL) in lysosomes and the Golgi apparatus (3)(4)(5)(6)(7). This biochemical phenotype is displayed by cells from NPC patients (3)(4)(5)(6)(7), cells from mice homozygous for the spontaneously occurring C57BLKS͞Jspm and BALB͞c npcnih mutations (8), in addition to Chinese hamster ovary cell mutants generated in the laboratory, including the CT60 line (9)(10)(11)(12).…”

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confidence: 99%

Niemann-Pick C1 protein: Obligatory roles for N-terminal domains and lysosomal targeting in cholesterol mobilization

Watari

Blanchette‐Mackie

Dwyer

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

142

104

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Niemann-Pick type C (NPC) disease is an inherited lipid storage disorder that affects the viscera and central nervous system. A characteristic feature of NPC cells is the lysosomal accumulation of low density lipoproteinderived cholesterol. To elucidate important structural features of the recently identified NPC1 gene product defective in NPC disease, we examined the ability of wild-type NPC1 and NPC1 mutants to correct the excessive lysosomal storage of low density lipoprotein-derived cholesterol in a model cell line displaying the NPC cholesterol-trafficking defect (CT60 Chinese hamster ovary cells). CT60 cells transfected with human wild-type NPC1 contained immunoreactive proteins of 170 and 190 kDa localized to the lysosomal͞endosomal compartment. Wild-type NPC1 protein corrected the NPC cholesteroltrafficking defect in the CT60 cells. Mutation of conserved cysteine residues in the NPC1 N terminus to serine residues resulted in proteins targeted to lysosomal membranes encircling cholesterol-laden cores, whereas deletion of the Cterminal 4-aa residues containing the LLNF lysosometargeting motif resulted in the expression of protein localized to the endoplasmic reticulum. None of these mutant NPC1 proteins corrected the NPC cholesterol-trafficking defect in CT60 cells. We conclude that transport of the NPC1 protein to the cholesterol-laden lysosomal compartment is essential for expression of its biological activity and that domains in the N terminus of the NPC1 protein are critical for mobilization of cholesterol from lysosomes.

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“…It is proposed that there are three mechanisms for sterol transport: aqueous diffusion, vesicular transport and/or carrier proteins [35]. Several candidate sterol transporters have been identified in mammalian cell lines [36,37]; however, there are still many aspects that remain unclear.…”

Section: Transportmentioning

confidence: 99%

Homoeostatic systems for sterols and other lipids

Garbarino

Sturley

2005

Biochemical Society Transactions

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Fatty acids and sterols are vital components of all eukaryotic cells. Both are used as building blocks for numerous cellular processes such as membrane biosynthesis or hormone production (sterols). Furthermore, these compounds elicit a variety of effects intracellularly as they can act as signalling molecules and regulate gene expression. The metabolism of fatty acids and sterols represents a very intricate network of pathways that are regulated in a precise manner in order to maintain lipid homoeostasis within a cell. Using the budding yeast Saccharomyces cerevisiae as a model system, we touch upon some of the aspects of achieving and maintaining this lipid homoeostasis.

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Chinese hamster ovary cell mutants affecting cholesterol metabolism

Cited by 31 publications

References 0 publications

Elevated levels of SREBP-2 and cholesterol synthesis in livers of mice homozygous for a targeted disruption of the SREBP-1 gene.

Elevated levels of SREBP-2 and cholesterol synthesis in livers of mice homozygous for a targeted disruption of the SREBP-1 gene.

Niemann-Pick C1 protein: Obligatory roles for N-terminal domains and lysosomal targeting in cholesterol mobilization

Homoeostatic systems for sterols and other lipids

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