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Viegas J. Profile of Ta-Yuan Chang. Proc Natl Acad Sci U S A 2022; 119:e2205427119. [PMID: 35471907 PMCID: PMC9171342 DOI: 10.1073/pnas.2205427119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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2
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Zhang M, Cao TT, Wei ZG, Zhang YQ. Silk Sericin Hydrolysate is a Potential Candidate as a Serum-Substitute in the Culture of Chinese Hamster Ovary and Henrietta Lacks Cells. JOURNAL OF INSECT SCIENCE (ONLINE) 2019; 19:5300249. [PMID: 30690536 PMCID: PMC6346402 DOI: 10.1093/jisesa/iey137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Indexed: 05/05/2023]
Abstract
The silk sericin hydrolysate (SSH) from the waste of silk processing as a substitute of fetal bovine serum (FBS) was used for the culture of Chinese hamster ovary (CHO) cells and Henrietta Lacks (Hela) strain of human cervical cancer cells. The survival ratio of these cells cultured in SSH media were similar to or higher than those in FBS media. Especially after the serum was replaced by low concentration of SSH at 15.0 μg/ml for 5 d, the proliferation of both cells was also similar to or higher than that of FBS group; the percentages of CHO and Hela cells in S-phase were 28.9 and 28.0%, respectively. The former is nearly two times that of FBS group, the latter is also higher than the control group. Reverse transcription-polymerase chain reaction (RT-PCR) revealed that among the differentially expressed genes, the relative expression of CXCL12 gene of CHO cells in SSH group increased, was three times that of serum group, and the relative expression of LCN2 gene of Hela cells increased 2.8 times, indicating that these related genes were activated to promote cell growth and proliferation. These results fully illustrated the hydrolysated sericin has a potential use as serum substitutes in cell culture.
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Affiliation(s)
- Meng Zhang
- Silk Biotechnology Laboratory, School of Biology and Basic Medical Sciences, Soochow University; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, PR China
| | - Ting-Ting Cao
- Silk Biotechnology Laboratory, School of Biology and Basic Medical Sciences, Soochow University; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, PR China
| | - Zheng-Guo Wei
- Silk Biotechnology Laboratory, School of Biology and Basic Medical Sciences, Soochow University; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, PR China
| | - Yu-Qing Zhang
- Silk Biotechnology Laboratory, School of Biology and Basic Medical Sciences, Soochow University; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, PR China
- Corresponding author, e-mail: (Y.-Q. Zhang)
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3
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Liu L, Wang J, Duan S, Chen L, Xiang H, Dong Y, Wang W. Systematic evaluation of sericin protein as a substitute for fetal bovine serum in cell culture. Sci Rep 2016; 6:31516. [PMID: 27531556 PMCID: PMC4987615 DOI: 10.1038/srep31516] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/21/2016] [Indexed: 12/22/2022] Open
Abstract
Fetal bovine serum (FBS) shows obvious deficiencies in cell culture, such as low batch to batch consistency, adventitious biological contaminant risk, and high cost, which severely limit the development of the cell culture industry. Sericin protein derived from the silkworm cocoon has become increasingly popular due to its diverse and beneficial cell culture characteristics. However, systematic evaluation of sericin as a substitute for FBS in cell culture medium remains limited. In this study, we conducted cellular morphological, physiological, and transcriptomic evaluation on three widely used mammalian cells. Compared with cells cultured in the control, those cultured in sericin-substitute medium showed similar cellular morphology, similar or higher cellular overall survival, lower population doubling time (PDT), and a higher percentage of S-phase with similar G2/G1 ratio, indicating comparable or better cell growth and proliferation. At the transcriptomic level, differentially expressed genes between cells in the two media were mainly enriched in function and biological processes related to cell growth and proliferation, reflecting that genes were activated to facilitate cell growth and proliferation. The results of this study suggest that cells cultured in sericin-substituted medium perform as well as, or even better than, those cultured in FBS-containing medium.
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Affiliation(s)
- Liyuan Liu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650223, China
| | - Jinhuan Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Shengchang Duan
- Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming 650500, China
| | - Lei Chen
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650223, China
| | - Hui Xiang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- South China Normal University, Guangzhou, 510631, China
| | - Yang Dong
- Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming 650500, China
| | - Wen Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming 650500, China
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4
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Maeda M, Ishida A, Ni L, Kobayashi A. Isolation of CHO-K1 clones defective in cAMP-dependent proteolysis, as determined by the stability of exogenously expressed GATA-6. Biochem Biophys Res Commun 2005; 329:140-6. [PMID: 15721285 DOI: 10.1016/j.bbrc.2005.01.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Indexed: 12/01/2022]
Abstract
Degradation of the GATA-6(Delta50) protein expressed in a CHO-K1 clone (tc1-17a) is stimulated in the presence of dbcAMP through proteasome without new protein synthesis [FEBS Lett. 408 (1997) 301], whereas the intrinsic GC-box-binding protein was stable. To examine the cellular mechanism responsible for this specific degradation of GATA-6(Delta50), we initially introduced the blasticidin-S deaminase gene carrying a promoter with GATA motifs that are recognized by GATA-6. The resulting cell line (tc2G2) grew in the presence of blasticidin S. However, the presence of both blasticidin S and dbcAMP was lethal due to degradation of GATA-6. Cells resistant to such lethality were isolated by chemical mutagenesis. The GATA-6(Delta50) in these resistant cells was stable in the presence of dbcAMP in contrast to that in the parent tc2G2 cells, as determined by gel-mobility shift analysis and Western blotting. These clones could be beneficial for identification and characterization of the components participating in the signaling pathway for both protein degradation and cAMP-dependent biological processes.
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Affiliation(s)
- Masatomo Maeda
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan.
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5
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Goldstein JL, Rawson RB, Brown MS. Mutant mammalian cells as tools to delineate the sterol regulatory element-binding protein pathway for feedback regulation of lipid synthesis. Arch Biochem Biophys 2002; 397:139-48. [PMID: 11795864 DOI: 10.1006/abbi.2001.2615] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The tools of somatic cell genetics have been instrumental in unraveling the pathway by which sterol regulatory element-binding proteins (SREBPs) control lipid metabolism in animal cells. SREBPs are membrane-bound transcription factors that enhance the synthesis and uptake of cholesterol and fatty acids. The activities of the SREBPs are controlled by the cholesterol content of cells through feedback inhibition of proteolytic processing. When cells are replete with sterols, SREBPs remain bound to membranes of the endoplasmic reticulum (ER) and are therefore inactive. When cells are depleted of sterols, the SREBPs move to the Golgi complex where two proteases release the active portions of the SREBPs, which then enter the nucleus and activate transcription of target genes. This processing requires three membrane proteins-a sterol-sensing escort protein (SCAP) that transports SREBPs from the ER to the Golgi and two Golgi-located proteases (S1P and S2P) that release SREBPs from membranes. The existence of all three proteins was revealed through analysis of mutant mammalian cells in tissue culture. Their cDNAs and genes were isolated by genetic complementation or by expression cloning. The somatic cell genetic approach described in this article should prove useful for unraveling other complex biochemical pathways in animal cells.
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Affiliation(s)
- Joseph L Goldstein
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046, USA.
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6
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Plemenitas A, Watson JA. Down-regulation of mammalian 3-hydroxy-3-methylglutaryl coenzyme A reductase activity with highly purified liposomal cholesterol. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 266:317-26. [PMID: 10561571 DOI: 10.1046/j.1432-1327.1999.00829.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chinese hamster ovary-215 cells (CHO-215) cannot synthesize C27 and C28 sterols because of a defect in the reaction that decarboxylates 4-carboxysterols [Plemenitas, A., Havel, C.M. & Watson, J.A. (1990) J. Biol. Chem. 265, 17012-17017]. Thus, CHO-215 cell growth is dependent on an exogenous metabolically functional source of cholesterol. We used CHO-215 cells to (a) determine whether highly purified (> 99.5%) cholesterol, in egg lecithin liposomes, could down-regulate derepressed 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity and if so (b) determine whether the loss in reductase catalytic activity correlated kinetically with the synthesis and accumulation of detectable oxycholesterol derivatives. Liposomal cholesterol (26-39 microM) supported maximum CHO-215 growth and initiated suppression of HMG-CoA reductase activity at concentrations greater than 50 microM. Maximum suppression (50-60%) of reductase activity was achieved with 181.3 microM liposomal cholesterol in 6 h. Also, regulatory concentrations of highly purified liposomal [3H]cholesterol were not converted (biologically or chemically) to detectable levels of oxy[3H]cholesterol derivatives during 3-6 h incubations. Lastly, a broad-spectrum cytochrome P450 inhibitor (miconazole) had no effect on liposomal cholesterol-mediated suppression of HMG-CoA reductase activity. These observations established that (a) highly purified cholesterol, incorporated into egg lecithin liposomes, can signal the down-regulation of derepressed mammalian cell HMG-CoA reductase activity and (b) if oxycholesterol synthesis was required for liposomal cholesterol-mediated down-regulation, the products had to be more potent than 24-, 25-, or 26-/27-hydroxycholesterol.
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Affiliation(s)
- A Plemenitas
- Institute of Biochemistry, Medical Faculty of the University of Ljubljana, Slovenia
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7
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Rietveld A, Simons K. The differential miscibility of lipids as the basis for the formation of functional membrane rafts. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1376:467-79. [PMID: 9805010 DOI: 10.1016/s0304-4157(98)00019-7] [Citation(s) in RCA: 410] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The formation of sphingolipid-cholesterol microdomains in cellular membranes has been proposed to function in sorting and transport of lipids and proteins as well as in signal transduction. An increasing number of cell biological and biochemical studies now supports this concept. Here we discuss the structural properties of lipids in a cell biological context. The sphingolipid-cholesterol microdomains or rafts are described as dispersed liquid ordered phase domains. These domains are dynamic assemblies to which specific proteins are selectively sequestered while others are excluded. The proteins associated to rafts can act as organizers and can modulate raft size and function.
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Affiliation(s)
- A Rietveld
- European Molecular Biology Laboratory, Cell Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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8
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7-Dehydrocholesterol down-regulates cholesterol biosynthesis in cultured Smith-Lemli-Opitz syndrome skin fibroblasts. J Lipid Res 1998. [DOI: 10.1016/s0022-2275(20)33302-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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9
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Ruan B, Gerst N, Emmons GT, Shey J, Schroepfer GJ. Sterol synthesis. A timely look at the capabilities of conventional and silver ion high performance liquid chromatography for the separation of C27 sterols related to cholesterol biosynthesis. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)30045-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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10
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Ruan B, Shey J, Gerst N, Wilson WK, Schroepfer GJ. Silver ion high pressure liquid chromatography provides unprecedented separation of sterols: application to the enzymatic formation of cholesta-5,8-dien-3 beta-ol. Proc Natl Acad Sci U S A 1996; 93:11603-8. [PMID: 8876182 PMCID: PMC38104 DOI: 10.1073/pnas.93.21.11603] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We report that silver ion HPLC provides remarkable separations of C27 sterols differing only in the number or location of olefinic double bonds. This technique has been extended to LC-MS, analysis of purified components by GC, GC-MS, and 1H NMR, and to its use on a semipreparative scale. The application of this methodology for the demonstration of the catalysis, by rat liver microsomes, of the conversion of 7-dehydrocholesterol to cholesta-5,8-dien-3 beta-ol is also presented.
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Affiliation(s)
- B Ruan
- Department of Chemistry, Rice University, Houston, TX 77251-1892, USA
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11
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Izumi A, Pinkerton F, Nelson S, Pyrek J, Neill P, Smith JH, Schroepfer G. Inhibitors of sterol synthesis. Submicromolar 14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta, 15 alpha-diol causes a major modification of the sterol composition of CHO-K1 cells and a marked change in cell morphology. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)39968-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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12
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Loss of transcriptional activation of three sterol-regulated genes in mutant hamster cells. Mol Cell Biol 1993. [PMID: 8102788 DOI: 10.1128/mcb.13.9.5175] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholesterol biosynthesis and uptake are controlled by a classic end product-feedback mechanism whereby elevated cellular sterol levels suppress transcription of the genes encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, and the low-density lipoprotein receptor. The 5'-flanking region of each gene contains a common cis-acting element, designated the sterol regulatory element (SRE), that is required for transcriptional regulation. In this report, we describe mutant Chinese hamster ovary (CHO) cell lines that lack SRE-dependent transcription. Mutant cell lines were isolated on the basis of their ability to survive treatment with amphotericin B, a polyene antibiotic that kills cells by interacting with cholesterol in the plasma membrane. Four mutant lines (SRD-6A, -B, -C, and -D) were found to be cholesterol auxotrophs and demonstrated constitutively low levels of mRNA for all three sterol-regulated genes even under conditions of sterol deprivation. The mutant cell lines were found to be genetically recessive, and all four lines belonged to the same complementation group. When transfected with a plasmid containing a sterol-regulated promoter fused to a bacterial reporter gene, SRD-6B cells demonstrated constitutively low levels of transcription, in contrast to wild-type CHO cells, which increased transcription under conditions of sterol deprivation. Mutation of the SREs in this plasmid prior to transfection reduced the level of expression in wild-type CHO cells deprived of sterols to the level of expression found in SRD-6B cells. The defect in SRD-6 cells is limited to transcriptional regulation, since posttranscriptional mechanisms of sterol-mediated regulation were intact: the cells retained the ability to posttranscriptionally suppress HMG-CoA reductase activity and to stimulate acyl-CoA:cholesterol acyltransferase activity. These results suggest that SRD-6 cells lack a factor required for SRE-dependent transcriptional activation. We contrast these cells with a previously isolated oxysterol-resistant cell line (SRD-2) that lacks a factor required for SRE-dependent transcriptional suppression and propose a model for the role of these genetically defined factors in sterol-mediated transcriptional regulation.
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13
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Evans MJ, Metherall JE. Loss of transcriptional activation of three sterol-regulated genes in mutant hamster cells. Mol Cell Biol 1993; 13:5175-85. [PMID: 8102788 PMCID: PMC360206 DOI: 10.1128/mcb.13.9.5175-5185.1993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cholesterol biosynthesis and uptake are controlled by a classic end product-feedback mechanism whereby elevated cellular sterol levels suppress transcription of the genes encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, and the low-density lipoprotein receptor. The 5'-flanking region of each gene contains a common cis-acting element, designated the sterol regulatory element (SRE), that is required for transcriptional regulation. In this report, we describe mutant Chinese hamster ovary (CHO) cell lines that lack SRE-dependent transcription. Mutant cell lines were isolated on the basis of their ability to survive treatment with amphotericin B, a polyene antibiotic that kills cells by interacting with cholesterol in the plasma membrane. Four mutant lines (SRD-6A, -B, -C, and -D) were found to be cholesterol auxotrophs and demonstrated constitutively low levels of mRNA for all three sterol-regulated genes even under conditions of sterol deprivation. The mutant cell lines were found to be genetically recessive, and all four lines belonged to the same complementation group. When transfected with a plasmid containing a sterol-regulated promoter fused to a bacterial reporter gene, SRD-6B cells demonstrated constitutively low levels of transcription, in contrast to wild-type CHO cells, which increased transcription under conditions of sterol deprivation. Mutation of the SREs in this plasmid prior to transfection reduced the level of expression in wild-type CHO cells deprived of sterols to the level of expression found in SRD-6B cells. The defect in SRD-6 cells is limited to transcriptional regulation, since posttranscriptional mechanisms of sterol-mediated regulation were intact: the cells retained the ability to posttranscriptionally suppress HMG-CoA reductase activity and to stimulate acyl-CoA:cholesterol acyltransferase activity. These results suggest that SRD-6 cells lack a factor required for SRE-dependent transcriptional activation. We contrast these cells with a previously isolated oxysterol-resistant cell line (SRD-2) that lacks a factor required for SRE-dependent transcriptional suppression and propose a model for the role of these genetically defined factors in sterol-mediated transcriptional regulation.
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Affiliation(s)
- M J Evans
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235
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14
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Ladenson R, Monsey J, Allin J, Silbert D. Utilization of exogenously supplied sphingosine analogues for sphingolipid biosynthesis in Chinese hamster ovary and mouse LM cell fibroblasts. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53007-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Complete replacement of membrane cholesterol with 4,4',14-trimethyl sterols in a human T cell line defective in lanosterol demethylation. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50353-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Abstract
The U.S. pharmaceutical industry has been criticized because its products are perceived to be too expensive, yet prescription medicines remain the least expensive form of therapy. At this time, we are experiencing a dramatic increase in the risks and costs of pharmaceutical research and development (R&D). An example may be seen in the R&D history of lovastatin. The U.S. pharmaceutical industry continues to lead the world in the discovery and development of important new medicines because it assumes greater financial risk and invests more of its sales dollar in R&D than virtually any other industry. Where such a risk is posed, there must continue to be the potential for profits. Pharmaceutical companies must set responsible prices, must keep price increases down, and must help improve access to important medicines.
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17
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Plemenitas A, Havel CM, Watson JA. Sterol-mediated regulation of mevalonic acid synthesis. Accumulation of 4-carboxysterols as the predominant sterols synthesized in a Chinese hamster ovary cell cholesterol auxotroph (mutant 215). J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)44861-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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18
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Maillot-Vernier P, Schaller H, Benveniste P, Belliard G. In Vitro Selection of Calli Resistant to a Triazole Cytochrome-P-450-Obtusifoliol-14-Demethylase Inhibitor from Protoplasts of Nicotiana tabacum L. cv Xanthi. PLANT PHYSIOLOGY 1990; 93:1190-5. [PMID: 16667577 PMCID: PMC1062650 DOI: 10.1104/pp.93.3.1190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The selection of biochemical mutants has been undertaken in order to elucidate regulatory and functional aspects of sterol biosynthesis in plants. 2-(4-Chlorophenyl)-3-phenyl-1-(1H-1,2,4- triazol-1-yl)-2,3-oxidopropane (LAB170250F), an experimental fungicide of the triazole family, was used as a selective agent. Indeed, this compound is a strong inhibitor of the cytochrome-P-450-obtusifoliol-14-demethylase in sterol biosynthesis. The selection strategy consisted of screening large populations of microcalli derived from ultraviolet-mutagenized protoplasts of Nicotiana tabacum L. cv Xanthi for resistance to a lethal concentration of LAB170250F. The best selective conditions were first determined, i.e. strength of the selection pressure as well as the time and duration of its application in the developmental process from protoplast to whole plant. Selection experiments resulted in the recovery of 40 resistant calli. These calli were divided into three classes according to the modification of their sterol content in response to LAB170250F. Some of these calli might be impaired in sterol biosynthesis, but most have a sterol profile identical to that of the control calli. This suggests that the toxic properties of LAB170250F are due to the parallel inhibition of sterol biosynthesis and of at least one additional unidentified target in the plant cell.
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Affiliation(s)
- P Maillot-Vernier
- Laboratoire de Biologie et Biochimie du Développement des Plantes, URA CNRS 1182, Université Louis Pasteur, 28 rue Goethe, 67083 Strasbourg Cedex, France
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19
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Panini SR, Schnitzer-Polokoff R, Spencer TA, Sinensky M. Sterol-independent Regulation of 3-Hydroxy-3-methylglutaryl-CoA Reductase by Mevalonate in Chinese Hamster Ovary Cells. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)60424-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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21
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Burki E, Logel J, Sinensky M. Endogenous sterol synthesis is not required for regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase by low density lipoprotein. J Lipid Res 1987. [DOI: 10.1016/s0022-2275(20)38609-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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22
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Billheimer JT, Chamoun D, Esfahani M. Defective 3-ketosteroid reductase activity in a human monocyte-like cell line. J Lipid Res 1987. [DOI: 10.1016/s0022-2275(20)38660-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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24
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Tomita K, Ono M, Masuda A, Akiyama S, Kuwano M. Defective endocytosis of low-density lipoprotein in monensin-resistant mutants of the mouse Balb/3T3 cell line. J Cell Physiol 1985; 123:369-76. [PMID: 3988813 DOI: 10.1002/jcp.1041230312] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two monensin-resistant clones show similar low-density lipoprotein binding activity but less internalization or degradation of low-density lipoprotein than the parental Balb/3T3 or other resistant clone. Sterol synthesis from radioactive acetate in the resistant mutant, MO-5, is inhibited by more than 70% of control in the presence of tenfold higher amounts of low-density lipoprotein than the dose that inhibits the parental Balb/3T3 to similar level. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity of Balb/3T3 and MO-5 is inhibited by 48% and 27% of control, respectively, in the presence of 10 micrograms/ml of low-density lipoprotein. Colloidal silica gradient centrifugation shows that transport of low-density lipoprotein from the surface membrane to the lysosome is much slower in MO-5 cells than in Balb/3T3 cells. Down regulation of low-density lipoprotein receptors on the cell surface in Balb/3T3 is observed by exposing the cells to 5-15 micrograms/ml low-density lipoprotein, whereas only slight if any down regulation is observed when MO-5 cells are treated with low-density lipoprotein. The altered endocytosis of low-density lipoprotein behaves as a dominant trait in hybrids of MO-5 and THO2-2, a derivative of Balb/3T3 resistant to both ouabain and 6-thioguanine.
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25
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Chen HW, Leonard DA. Chloroquine inhibits cyclization of squalene oxide to lanosterol in mammalian cells. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)39707-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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26
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Ohno K, Nakano C, Eda I, Takeshita K. Fibroblasts from patients with myotonic muscular dystrophy: cholesterol requirement for proliferation and sensitivity to polyene antibiotics. Brain Dev 1984; 6:566-70. [PMID: 6534201 DOI: 10.1016/s0387-7604(84)80102-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The genetic defect in myotonic muscular dystrophy (MMD) remains obscure. From the evidence that drugs blocking cholesterol biosynthesis induce myotonia and increased serum concentrations of deoxycholic acids are common among patients with MMD, evidence of the abnormal sterol metabolism in MMD fibroblasts was sought by comparing them with fibroblasts from control individuals and patients with Duchenne muscular dystrophy (DMD). Although early-onset type MMD and DMD fibroblasts have lower maximal cell densities than fibroblasts from age-matched control individuals do in medium containing 10% fetal bovine serum, we could not reveal any abnormalities in exogeneous cholesterol requirements for proliferation of MMD fibroblasts. This suggests that the sterol biosynthetic pathway in MMD fibroblasts is grossly intact. Furthermore, no difference were observed in sensitivities to polyene antibiotics, which bind to membrane sterols and presumably damage the cell membrane.
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Kuwano M, Masuda A, Hidaka K, Akiyama SI. Secondary mutation resistant to 7-ketocholesterol rescues a sterol metabolic defect in amphotericin B-resistant Chinese hamster cell line. SOMATIC CELL GENETICS 1983; 9:659-72. [PMID: 6658643 DOI: 10.1007/bf01539471] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Amphotericin B-resistant mutants isolated from Chinese hamster V79 cells (1) are defective in cholesterol synthesis and more sensitive to an oxygenated sterol analog, 7-ketocholesterol, than their parental cell line. We isolated 7-ketocholesterol-resistant mutants from an amphotericin B-resistant mutant, AMBR-1. The 7-ketocholesterol-resistant mutants had regained increased level of free cholesterol, and they showed somewhat similar dose-response curves to amphotericin B as that of V79. Sterol synthesis from acetate, but not from mevalonate, in 7-ketocholesterol-resistant clones was threefold higher than that of AMBR-1. 7-Ketocholesterol-resistant clone, unlike AMBR-1, could form colonies in the presence of lipoprotein-depleted serum. The results are discussed in terms of probable change in the sterol biosynthetic pathway by the different lesions.
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28
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Buttke TM, Chapman SW. Inhibition by ketoconazole of mitogen-induced DNA synthesis and cholesterol biosynthesis in lymphocytes. Antimicrob Agents Chemother 1983; 24:478-85. [PMID: 6316842 PMCID: PMC185359 DOI: 10.1128/aac.24.4.478] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The effects of ketoconazole on mitogen-induced DNA synthesis and cholesterol biosynthesis in human and murine lymphocytes have been examined. Ketoconazole concentrations which do not affect cell viability (0.1 to 10 micrograms/ml) in culture led to a dose-dependent inhibition of DNA synthesis, as measured by [3H]thymidine incorporation, induced by either T-cell or B-cell mitogens. At drug concentrations 5- to 10-fold lower, ketoconazole inhibited the incorporation of [14C]acetate into cholesterol, with a resultant accumulation of [14C]lanosterol. The suppressive effects of ketoconazole on DNA synthesis were reversed by increasing the concentration of human serum in the culture medium from 5 to 20%. The depletion of lipoproteins in human serum by density centrifugation reduced the cholesterol content by 90% but did not affect the ability of the serum to overcome the inhibition by ketoconazole of DNA synthesis. Unlike DNA synthesis, cholesterol biosynthesis was not restored by 20% fresh human serum or lipoprotein-depleted human serum. These results demonstrate that ketoconazole potently inhibits DNA synthesis and cholesterol synthesis in mitogen-stimulated lymphocytes at drug concentrations obtained therapeutically. Further, the uncoupling of endogenous cholesterol synthesis and DNA synthesis indicates at least two levels of action of ketoconazole in mammalian lymphocytes.
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29
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Patterson D, Vannais DB, Laas W. Isolation and characterization of a Chinese hamster ovary cell mutant which accumulates UDP glucuronic acid and requires uridine for growth. J Cell Physiol 1983; 116:257-64. [PMID: 6885929 DOI: 10.1002/jcp.1041160302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The isolation and characterization of a new pyrimidine requiring mutant of Chinese hamster ovary cells (CHO-Kl, pro-) is described. This mutant (P192) shows an absolute requirement for uridine for growth but is fully capable of pyrimidine nucleotide synthesis. P192 cells accumulate exceedingly large amounts of a compound identified by a variety of chromatographic, chemical, and labelling criteria as UDP glucuronic acid (UDPglcUA). This compound comprises approximately 60% of the acid-soluble nucleotides of P192 cells. Possible genetic mechanisms leading to the phenotype of P192 are examined, and the role of UDPglcUA in cellular metabolism is discussed.
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30
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31
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14 Mammalian HMG-CoA Reductase and Its Regulation. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s1874-6047(08)60312-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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32
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Emmons GT, Rosenblum ER, Peace JN, Malloy JM, Doerfler DL, McManus IR, Campbell IM. Effects of 20,25-diazacholesterol on cholesterol synthesis in cultured chick muscle cells: a radiogas chromatographic and mass spectrometric study of the post-squalene sector. BIOMEDICAL MASS SPECTROMETRY 1982; 9:278-285. [PMID: 7126761 DOI: 10.1002/bms.1200090703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Radiogas chromatography, used in conjunction with mass spectrometry, has been used to analyze the sterol content of cultured chick muscle cells. Seven sterols, plus lanosterol, were detected. These sterols conformed to a linear biosynthetic pathway linking lanosterol and cholesterol. The reaction sequence is: C-14 demethylation, C-4 demethylation, delta 8 leads to delta 5 double bond rearrangement, delta 24 double bond reduction. When chick cells were treated with increasing concentrations of 20,25-diazacholesterol, components of this pathway and aberrant products accumulated. These accumulations suggest that diazacholesterol affects reductases, double bond isomerases and the C-14 demethylation enzymes of sterol biosynthesis.
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33
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Berry DJ, Chang TY. Further characterization of a Chinese hamster ovary cell mutant defective in lanosterol demethylation. Biochemistry 1982; 21:573-80. [PMID: 7066308 DOI: 10.1021/bi00532a025] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Sensitive in vitro lanosterol 14 alpha- and 4 alpha-methylsterol oxidase assays, particularly suitable for cell extracts of tissue culture cells, were developed and validated. Using these assays, we showed that the biochemical lesion of mutant 215, a cholesterol-requiring Chinese hamster ovary cell auxotroph isolated and partially characterized previously [Chang, T. Y., Telakowski, C., Vanden Heuvel, W., Alberts, A. W., & Vagelos, P. R. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 832-836], was localized at the 4 alpha-methylsterol oxidase enzyme system. The defect in 4 alpha-methylsterol oxidase activity in mutant 215 cells could be demonstrated by using either 4,4-dimethylcholestanol or 4 alpha-methylcholestanol as the substrate, suggesting that the enzyme systems responsible for 4 alpha-methyl- and 4,4-dimethylsterols may share a common component. However, demethylation of the C-14 alpha methyl group was found to occur at identical rates in wild-type and mutant 215, suggesting that C-14 alpha demethylation and C-4 alpha demethylation may occur by separate enzyme systems. A [3H]dihydrolanosterol incorporation experiment in intact cells of wild-type and mutant 215 supported these conclusions. Despite these results, a [14C]acetate pulse experiment indicated that [14C]lanosterol, instead of its 14C-labeled 14-demethylated sterol derivative(s), accumulated in intact cells of mutant 215. Possible implications of these findings for the mechanisms of lanosterol demethylation reactions are discussed.
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34
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14 alpha-Ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol, a potent inhibitor of sterol biosynthesis, has two sites of action in cultured mammalian cells. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68128-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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35
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Schnitzer-Polokoff R, von Gunten C, Logel J, Torget R, Sinensky M. Isolation and characterization of a mammalian cell mutant defective in 3-hydroxy-3-methylglutaryl coenzyme A synthase. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68388-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Chin J, Chang T. Evidence for coordinate expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase ad low density lipoprotein binding activity. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69163-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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37
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Rip J, Rupar C, Chaudhary N, Carroll K. Localization of a dolichyl phosphate phosphatase in plasma membranes of rat liver. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69896-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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38
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Hidaka K, Akiyama SI, Kuwano M. Amphotericin B resistance is recessive in Chinese hamster hybrid cells. J Cell Physiol 1981; 106:41-7. [PMID: 6937470 DOI: 10.1002/jcp.1041060106] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Previous studies from our laboratory have shown that Chinese hamster V79 cells mutated to high level resistance to amphotericin B have a lower cellular level of cholesterol, the target molecule for the polyene antibiotic. Two amphotericin B-resistant (AMBR) mutants were each hybridized to their parental amphotericin B-sensitive (AMBS) V79 cells. All the hybrids derived from AMBR/AMBS fusions were as sensitive to polyene antibiotics (amphotericin B, filipin, and pimaricin) as AMBS cells or AMBS/AMBS hybrids. The AMBR/AMBS hybrids were found to contain cholesterol per phospholipids that is comparable to those in AMBS or AMBS/AMBS. The analysis of hybrids formed between mutant and wild-type cells thus indicated that resistance to amphotericin B is a recessive marker, and that the cellular level of cholesterol is compensated in the AMBS/AMBR hybrids. Hybrids of AMBR and AMBR cells were all resistant, so that the three AMBR mutants all fell into a single complementation group.
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39
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Hochstadt J, Ozer HL, Shopsis C. Genetic alteration in animal cells in culture. Curr Top Microbiol Immunol 1981; 94-95:243-308. [PMID: 6171390 DOI: 10.1007/978-3-642-68120-2_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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40
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Chang T, Limanek J. Regulation of cytosolic acetoacetyl coenzyme A thiolase, 3-hydroxy-3-methylglutaryl coenzyme A synthase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and mevalonate kinase by low density lipoprotein and by 25-hydroxycholesterol in Chinese hamster ovary cells. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)43901-x] [Citation(s) in RCA: 131] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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41
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Van den Bossche H, Willemsens G, Cools W, Cornelissen F, Lauwers WF, van Cutsem JM. In vitro and in vivo effects of the antimycotic drug ketoconazole on sterol synthesis. Antimicrob Agents Chemother 1980; 17:922-8. [PMID: 6250469 PMCID: PMC283904 DOI: 10.1128/aac.17.6.922] [Citation(s) in RCA: 214] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Ketoconazole, an orally active antimycotic drug, is a potent inhibitor of ergosterol biosynthesis in Candida albicans when added to culture media which support yeast or mycelial growth or to cultures containing outgrown mycelium. This inhibition coincides with accumulation of sterols with a methyl group at C-14 and can thus be attributed to an interference with one of the reactions involved in the removal of the 14 alpha-methyl group of lanosterol. When administered to rats infected with C. albicans, ketocanazole also inhibits fungal synthesis of ergosterol. A six-times-higher dose is required to effect cholesterol synthesis by rat liver.
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42
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Mutants of Chinese hamster ovary cells with altered membrane phospholipid composition. Replacement of phosphatidylinositol by phosphatidylglycerol in a myo-inositol auxotroph. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85515-1] [Citation(s) in RCA: 142] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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43
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Dahl CE, Dahl JS, Bloch K. Effect of alkyl-substituted precursors of cholesterol on artificial and natural membranes and on the viability of Mycoplasma capricolum. Biochemistry 1980; 19:1462-7. [PMID: 7388005 DOI: 10.1021/bi00548a031] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Various alkyl-substituted sterols and stanols representative of the intermediates in cholesterol biosynthesis from lanosterol have been compared with respect to (a) their effect on the physical state of lecithin vesicles, (b) their efficacy as growth factors for the sterol auxotroph Mycoplasma capricolum, and (c) their effect on the physical state of the respective mycoplasma membranes. By all three criteria, sterol effectiveness progresses in the order lanosterol less than 4,4-dimethylcholestanol less than or equal to 4 beta-methylcholestanol less than 4 alpha-methylcholestanol less than cholestanol less than cholesterol. Since the corresponding steps in cholesterol biosynthesis occur in the same order, we conclude that the nuclear modifications of the lanosterol structure by oxidative demethylation serve to improve the membrane function of the sterol molecule.
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44
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Bloch KE. Speculations on the evolution of sterol structure and function. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1979; 7:1-5. [PMID: 498798 DOI: 10.3109/10409237909102566] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The essential oxygen requirement for sterol biosynthesis dates this molecule as a relative latecomer in cellular evolution. Structural details of the cholesterol molecule and related sterols can be rationalized in terms of optimal hydrophobic interactions between the planar sterol ring system and phospholipid acyl chains in the membrane bilayer. The prediction that the cholesterol precursor lanosterol (4,4',14 trimethyl cholastadienol) is incompetent for membrane function is verified by in vivo experiments with eucaryotic sterol auxotrophs and microviscosity measurements of sterol-containing artificial membranes. For procaryotic cells the sterol specificity is very much broader. Methylococcus capsulatus produces 4,4-dimethyl- and 4-monomethyl sterols, but not sterols of the cholesterol type. Similarly lanosterol and its partially demethylated derivatives satisfy the sterol requirement of Mycoplasma capricolum. A more primitive but unspecified role of cyclized squalene derivatives is therefore postulated for procaryotic membranes. The finding that cholesterylmethyl ether satisfies the sterol requirement of certain microbial systems is at variance with current views on the role played by the sterol hydroxyl group in membrane organization and function.
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45
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Chang T, Schiavoni E, McCrae K, Nelson J, Spencer T. Inhibition of cholesterol biosynthesis in Chinese hamster ovary cells by 4,4,10 beta-trimethyl-trans-decal-3 beta-ol. A specific 2,3-oxidosqualene cyclase inhibitor. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86479-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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46
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Saito Y, Silbert D. Selective effects of membrane sterol depletion on surface function thymidine and 3-O-methyl-D-glucose transport in a sterol auxotroph. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)34173-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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47
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Limanek JS, Chin J, Chang TY. Mammalian cell mutant requiring cholesterol and unsaturated fatty acid for growth. Proc Natl Acad Sci U S A 1978; 75:5452-6. [PMID: 281693 PMCID: PMC392982 DOI: 10.1073/pnas.75.11.5452] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A mutant requiring both cholesterol and oleate for growth has been isolated from mutagenized Chinese hamster ovary cells. By comparison with wild-type cells, sterol and unsaturated fatty acid biosynthetic activities in the mutant cells grown in fetal calf serum medium appear to be nearly intact. However, whole-cell radioactive acetate, mevalonate, dihydrolanosterol, and stearate incorporation studies show that sterol synthesis from acetate, lanosterol demethylation, and fatty acid desaturation are defective in the mutant cells grown in delipidated serum medium. In vitro enzyme assays with crude cell extracts demonstrated that beta-hydroxy-beta-methylglutaryl-coenzyme A reductase is not induced in the mutant. These experiments were substantiated by gas/liquid chromatographic analyses which showed the sterol content and the percentage unsaturated fatty acids in mutant cells to be drastically reduced when the cells are grown in delipidated serum medium. A spontaneous revertant exhibiting prototrophic growth in lipid-free medium has been isolated from 50 X 10(6) mutant cells. All three defects in this revertant reverted back in parallel, which suggests that these three biosynthetic activities may be controlled by a common regulatory mechanism.
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48
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Odriozola JM, Waitzkin E, Smith TL, Bloch K. Sterol requirement of Mycoplasma capricolum. Proc Natl Acad Sci U S A 1978; 75:4107-9. [PMID: 279900 PMCID: PMC336060 DOI: 10.1073/pnas.75.9.4107] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mycoplasmas require an external source of sterol for growth. For Mycoplasma capricolum this requirement is met not only by cholesterol but also by the methylcholestane derivatives lanosterol, cycloartenol, 4,4-dimethylcholesterol, and 4beta-methylcholestanol. Cholesteryl methyl ether and 3alpha-methylcholestanol serve equally well as sterol supplements. None of the growth-supporting sterol derivatives tested was metabolically modified. The unusual acceptance of diverse cholestane derivatives by a mycoplasma species contrasts with the structural attributes thought to be necessary for sterol function in eukaryotic membranes.
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49
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Doi O, Endo A. Specific inhibition of desmosterol synthesis by ML--236B in mouse LM cells grown in suspension in a lipid-free medium. JAPANESE JOURNAL OF MEDICAL SCIENCE & BIOLOGY 1978; 31:225-33. [PMID: 732030 DOI: 10.7883/yoken1952.31.225] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The suspended growth of LM cells in a lipid-free chemically defined medium was almost completely inhibited in the presence of 0.1 microgram/ml of ML-236B, a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate limiting enzyme in cholesterol biosynthesis in mammalian cells. This inhibition was effectively counteracted by adding a small amount of either mevalonate or cholesterol (dispersed in delipidated calf serum) to culture medium. The synthesis of desmosterol, the end product of sterol biosynthesis in LM cells, from [14C]acetate in cultured cells was highly sensitive to ML-236B, being inhibited 35 and 60% at its concentrations of 0.1 and 1 ng/ml, respectively, while the incorporation of [3H]mevalonate into desmosterol was not affected by ML-236B at concentrations up to 0.1 microgram/ml. Synthesis of fatty acids, phospholipids, triglycerides and macromolecules like DNA, RNA and protein were not suppressed by 10 microgram/ml of ML-236B. Desmosterol content of LM cells was reduced by treatment with ML-236B. These results indicate that ML-236B inhibited cell growth via specific interference in the pathway of sterol biosynthesis, presumably on the step catalyzed by HMG-CoA reductase.
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50
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Esko JD, Raetz CR. Replica plating and in situ enzymatic assay of animal cell colonies established on filter paper. Proc Natl Acad Sci U S A 1978; 75:1190-3. [PMID: 349559 PMCID: PMC411435 DOI: 10.1073/pnas.75.3.1190] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have developed a simple technique for the replica plating of Chinese hamster ovary (CHO) cells. In this procedure cells are allowed to divide for 8-16 days between the plastic surface of a petri dish and a disc of Whatman no. 50 filter paper, weighted down with glass beads. The culture medium can be replaced when necessary without disturbing the growing colonies. Cells from each developing colony grow into the fibers of the paper, while others remain attached to the plate. The cell colonies transferred to the paper are viable and can be replica plated to a new petri dish with high resolution. In this way several inositol auxotrophs have been identified in a stock of mutagen-treated cells without prior enrichment. Alternatively, the cells on the paper can be rendered permeable in situ, which permits autoradiographic screening for specific biochemical defects, as reported previously for Escherichia coli [Raetz, C. R.H. (1975 Proc. Natl. Acad. Sci. USA 72, 2274-2278]. This technique is applicable to other common cell lines and is especially useful for the identification of single colonies defective in the synthesis of DNA, RNA, protein, and membrane lipids.
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