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Li F, Ebihara A, Sakahara Y, Matsumoto S, Ueno R, Bao W, Kimura M, Fuji SI, Shimizu M, Kageyama K, Suga H. Synergistic effect of amino acid substitutions in CYP51B for prochloraz resistance in Fusarium fujikuroi. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 189:105291. [PMID: 36549812 DOI: 10.1016/j.pestbp.2022.105291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 06/17/2023]
Abstract
Prochloraz has been used to control Fusarium fujikuroi, the causative pathogen of rice bakanae disease. Linkage analysis of FfCYP51 genes in the progenies obtained from crossing prochloraz moderately resistant and sensitive strains suggested that the FfCYP51B gene is involved in prochloraz resistance. Sequence comparison revealed that the prochloraz-resistant strain had an F511S or S312T/F511S substitution in FfCYP51B compared with the sensitive strains. The contribution of the S312T and F511S substitutions in FfCYP51B to prochloraz resistance was investigated by creating S/F-, T/F-, or T/S- types at 312/511 codons from the S/S-type, which is a natural moderately resistant strain, using a gene-editing technique. T/S exhibited the highest prochloraz resistance, followed by S/S-, T/F-, and S/F-types. These results indicated that the S312T and F511S substitutions in FfCYP51B had a synergistic effect on prochloraz resistance in F. fujikuroi.
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Affiliation(s)
- FangJing Li
- The United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Akio Ebihara
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yuri Sakahara
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Sarara Matsumoto
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Reina Ueno
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - WanXue Bao
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Makoto Kimura
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Shin-Ichi Fuji
- Faculty of Bioresource Sciences, Akita Prefectural University, 241-438 Kaidobata-Nishi Nakano Shimoshinjo, Akita 010-0195, Japan
| | - Masafumi Shimizu
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Koji Kageyama
- River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Haruhisa Suga
- Institute for Glyco-core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan..
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2
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Pulya S, Kommagalla Y, Sant DG, Jorwekar SU, Tupe SG, Deshpande MV, Ramana CV. Re-engineering of PIP3-antagonist triazole PITENIN's chemical scaffold: development of novel antifungal leads. RSC Adv 2016. [DOI: 10.1039/c5ra25145a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A novel 4-(1-phenyl-1-hydroxyethyl)-1-(o-hydroxyphenyl)-1H-1,2,3-triazole was designed by integrating the structural features of triazole PITENIN anticancer agents and the azole class of antifungal drugs.
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Affiliation(s)
- Sravani Pulya
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Yadagiri Kommagalla
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Duhita G. Sant
- Biochemical Sciences Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Shweta U. Jorwekar
- Biochemical Sciences Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Santosh G. Tupe
- Biochemical Sciences Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Mukund V. Deshpande
- Biochemical Sciences Division
- CSIR-National Chemical Laboratory
- Pune-411008
- India
| | - Chepuri V. Ramana
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Pune-411008
- India
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3
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Use of chemical auxiliaries to control p450 enzymes for predictable oxidations at unactivated C-h bonds of substrates. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 851:209-28. [PMID: 26002737 DOI: 10.1007/978-3-319-16009-2_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cytochrome P450 enzymes (P450s) have the ability to oxidize unactivated C-H bonds of substrates with remarkable regio- and stereoselectivity. Comparable selectivity for chemical oxidizing agents is typically difficult to achieve. Hence, there is an interest in exploiting P450s as potential biocatalysts. Despite their impressive attributes, the current use of P450s as biocatalysts is limited. While bacterial P450 enzymes typically show higher activity, they tend to be highly selective for one or a few substrates. On the other hand, mammalian P450s, especially the drug-metabolizing enzymes, display astonishing substrate promiscuity. However, product prediction continues to be challenging. This review discusses the use of small molecules for controlling P450 substrate specificity and product selectivity. The focus will be on two approaches in the area: (1) the use of decoy molecules, and (2) the application of substrate engineering to control oxidation by the enzyme.
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4
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Polic V, Auclair K. Controlling substrate specificity and product regio- and stereo-selectivities of P450 enzymes without mutagenesis. Bioorg Med Chem 2014; 22:5547-54. [PMID: 25035263 PMCID: PMC5177023 DOI: 10.1016/j.bmc.2014.06.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 01/25/2023]
Abstract
P450 enzymes (P450s) are well known for their ability to oxidize unactivated CH bonds with high regio- and stereoselectivity. Hence, there is emerging interest in exploiting P450s as potential biocatalysts. Although bacterial P450s typically show higher activity than their mammalian counterparts, they tend to be more substrate selective. Most drug-metabolizing P450s on the other hand, display remarkable substrate promiscuity, yet product prediction remains challenging. Protein engineering is one established strategy to overcome these issues. A less explored, yet promising alternative involves substrate engineering. This review discusses the use of small molecules for controlling the substrate specificity and product selectivity of P450s. The focus is on two approaches, one taking advantage of non-covalent decoy molecules, and the other involving covalent substrate modifications.
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Affiliation(s)
- Vanja Polic
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Karine Auclair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
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Ménard A, Fabra C, Huang Y, Auclair K. Type II Ligands as Chemical Auxiliaries To Favor Enzymatic Transformations by P450 2E1. Chembiochem 2012; 13:2527-36. [DOI: 10.1002/cbic.201200524] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Indexed: 11/09/2022]
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6
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Liu X, Fu J, Yun Y, Yin Y, Ma Z. A sterol C-14 reductase encoded by FgERG24B is responsible for the intrinsic resistance of Fusarium graminearum to amine fungicides. Microbiology (Reading) 2011; 157:1665-1675. [DOI: 10.1099/mic.0.045690-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fusarium graminearum, the causal agent of wheat head blight, shows intrinsic resistance to amine fungicides. It is commonly accepted that the amines target sterol C-14 reductase and sterol Δ8–Δ7 isomerase of ergosterol biosynthesis, encoded by the genes ERG24 and ERG2, respectively. Analysis of the genome sequence of F. graminearum revealed that the fungus contains two paralogous FgERG24 genes (FgERG24A and FgERG24B), which are homologous to the ERG24 of Saccharomyces cerevisiae. In this study, we disrupted FgERG24A and FgERG24B in F. graminearum. Compared to the wild-type strain HN9-1, FgERG24A and FgERG24B deletion mutants did not show recognizable phenotypic changes in mycelial growth on potato dextrose agar or in virulence on wheat heads. HPLC analysis showed that the amount of ergosterol in FgERG24A or FgERG24B deletion mutants was not significantly different from that in the wild-type strain. These results indicate that neither of the two genes is essential for growth, pathogenicity or ergosterol biosynthesis in F. graminearum. FgERG24B deletion mutants exhibited significantly increased sensitivity to amine fungicides, including tridemorph, fenpropidin and spiroxamine, but not to non-amine fungicides. In contrast, FgERG24A deletion mutants did not show changed sensitivity to any amine tested. The resistance of the FgERG24B deletion mutant to amines was restored by genetic complementation of the mutant with wild-type FgERG24B. These results indicate that FgERG24B controls the intrinsic resistance of F. graminearum to amines. The finding of this study provides new insights into amine resistance in filamentous fungi.
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Affiliation(s)
- Xin Liu
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
| | - Jing Fu
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
| | - Yingzi Yun
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
| | - Yanni Yin
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
| | - Zhonghua Ma
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
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7
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Rice C, Cooke M, Treloar N, Vollbrecht P, Stukey J, McDonough V. A role for MGA2, but not SPT23, in activation of transcription of ERG1 in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2010; 403:293-7. [PMID: 21075079 DOI: 10.1016/j.bbrc.2010.11.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 11/08/2010] [Indexed: 11/25/2022]
Abstract
The SaccharomycescerevisiaeMGA2 gene encodes an important regulator of unsaturated fatty acid production, by controlling transcription and mRNA stability of OLE1, the gene encoding the Δ9 fatty acid desaturase. Lipid composition studies indicated that the mga2Δ strain contains elevated relative amounts of squalene when compared to wild-type cells. The deletion of the MGA2 homologue SPT23 did not impact squalene levels. To explore the role of MGA2 in the regulation of sterol synthesis, the transcription of the ERG1 gene, which encodes squalene epoxidase, was studied using an ERG1 promoter-lacZ reporter gene construct. We report here that in addition to MGA2's role in regulation of unsaturated fatty acids, MGA2 is required for full basal expression of ERG1. Mga2p was found to be controlled by a novel regulator in its activation of ERG1, as neither unsaturated fatty acids nor cobalt affected ERG1 expression, as had previously been shown for Mga2p's regulation of OLE1. Further, response to miconazole treatment, which inhibits production of ergosterol at a later step in the sterol biosynthetic pathway and results in up-regulation of several genes in ergosterol synthesis, was not affected in the mga2Δ mutant. In each case, the spt23Δ mutant strain shows similar ERG1 expression to wild-type cells, while the mga2Δ/spt23Δ strain shows reduced ERG1 expression, comparable to the mga2Δ, suggesting that the role of regulation of ERG1 transcription is unique to Mga2p.
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Affiliation(s)
- Caitlin Rice
- Department of Biology, Hope College, P.O. Box 9000, Holland, MI 49422-9000, USA
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8
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Hata M, Ishii Y, Watanabe E, Uoto K, Kobayashi S, Yoshida KI, Otani T, Ando A. Inhibition of ergosterol synthesis by novel antifungal compounds targeting C-14 reductase. Med Mycol 2010; 48:613-21. [PMID: 20392153 DOI: 10.3109/13693780903390208] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The limited number of clinically available antifungal drugs for life-threatening fungal infections has produced an increased demand for new agents. In the course of our screening for novel antifungals, we identified aminopiperidine derivatives which exhibit antifungal activities against the major pathogenic yeasts. Thin layer chromatography (TLC) analysis of the extracted non-saponifiable lipids from Candida albicans showed that these compounds inhibited the ergosterol production in the late step of the synthesis pathway. The results of an LC/Q-Tof MS analysis showed that abnormal sterols including predicted ignosterol, which is known to be accumulated in C. albicans ERG24 deleted mutant, were accumulated in C. albicans treated with one of these derivatives (Compound 1b). Furthermore, the partial disruption of the cell membrane of C. albicans treated with compound 1b was observed by electron microscopy analysis, suggesting its inhibition of ergosterol synthesis. Additionally, a genetic approach demonstrated that ERG24 gene would be responsible for the resistance of Saccharomyces cerevisiae against Compound 1b, strongly indicating that the enzyme targeted by Compound 1b is Erg24p. From all these data, we concluded that these aminopiperidine derivatives are novel antifungal compounds inhibiting C-14 reduction in the ergosterol synthesis pathway.
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Affiliation(s)
- Masato Hata
- Kasai R&D Center, Daiichi Sankyo Co., Ltd, Edogawa-ku, Tokyo, Japan.
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9
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Functional characterization of a C-4 sterol methyl oxidase from the endomycorrhizal fungus Glomus intraradices. Fungal Genet Biol 2009; 46:486-95. [PMID: 19285148 DOI: 10.1016/j.fgb.2009.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 02/20/2009] [Accepted: 03/03/2009] [Indexed: 01/26/2023]
Abstract
Sterols are crucial components of eukaryotic membranes that control membrane fluidity and permeability. They play an important role in cell signaling, polarity and sorting. Since many steps in the pathway are essential, sterol biosynthesis inhibitors (SBI) are widely used as antifungal agents. This work reports the identification and the characterization of a C-4 sterol methyl oxidase (SMO), the first gene involved in the sterol biosynthetic pathway, so far described from an arbuscular mycorrhizal fungus. The sequence, called GintSMO, shows a primary structure, a hydrophobicity profile and a pattern of histidine-rich motifs which are typical of C-4 methyl sterol oxidases. The complementation assay in a Saccharomyces cerevisiae mutant strain demonstrates that GintSMO encodes a functional SMO. Changes in GintSMO transcript levels and in the amount of the sterol precursor squalene were observed in in vitro grown extraradical structures exposed to the fenpropimorph SBI fungicide.
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10
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Sangamwar AT, Deshpande UD, Pekamwar SS. Antifungals: need to search for a new molecular target. Indian J Pharm Sci 2008; 70:423-30. [PMID: 20046765 PMCID: PMC2792545 DOI: 10.4103/0250-474x.44588] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 03/25/2008] [Accepted: 07/10/2008] [Indexed: 11/04/2022] Open
Abstract
In the 1990s, drug resistance has become an important problem in a variety of infectious diseases including human immunodeficiency virus infection, tuberculosis, and other bacterial infections which have profound effects on human health. At the same time, there have been dramatic increase in the incidence of fungal infections, which are probably the result of alterations in immune status associated with the acquired immuno deficiency syndrome epidemic, cancer chemotherapy, and organ and bone marrow transplantation. The rise in the incidence of fungal infections has exacerbated the need for the next generation of antifungal agents, since many of the currently available drugs have undesirable side effects, are ineffective against new or reemerging fungi, or lead to the rapid development of the resistance. This review will focus on the pathogenic yeast Candida albicans, since a large body of work on the factors and mechanism associated with antifungal drug resistance in this organism is reported sufficiently. It will certainly elaborate the probable molecular targets for drug design, discovered to date.
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Affiliation(s)
- A. T. Sangamwar
- Department of Pharmaceutics, Nanded Pharmacy College, Nanded-431 605, India
| | - U. D. Deshpande
- School of Life Sciences, S. R. T. M. University, Nanded-430 606, India
| | - S. S. Pekamwar
- Department of Pharmaceutical Chemistry, Nanded Pharmacy College, Nanded-431 605, India
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11
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Effects of two sterol biosynthesis inhibitor fungicides (fenpropimorph and fenhexamid) on the development of an arbuscular mycorrhizal fungus. ACTA ACUST UNITED AC 2008; 112:592-601. [DOI: 10.1016/j.mycres.2007.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/10/2007] [Accepted: 11/06/2007] [Indexed: 11/19/2022]
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12
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Palmer CP, Mahen R, Schnell E, Djamgoz MBA, Aydar E. Sigma-1 receptors bind cholesterol and remodel lipid rafts in breast cancer cell lines. Cancer Res 2007; 67:11166-75. [PMID: 18056441 DOI: 10.1158/0008-5472.can-07-1771] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lipid rafts are membrane platforms that spatially organize molecules for specific signaling pathways that regulate various cellular functions. Cholesterol is critical for liquid-ordered raft formation by serving as a spacer between the hydrocarbon chains of sphingolipids, and alterations in the cholesterol contents of the plasma membrane causes disruption of rafts. The role that sigma receptors play in cancer is not clear, although it is frequently up-regulated in human cancer cells and tissues and sigma receptors inhibit proliferation in carcinoma and melanoma cell lines, induce apoptosis in colon and mammary carcinoma cell lines, and reduce cellular adhesion in mammary carcinoma cell lines. In this study, we provide molecular and functional evidence for the involvement of the enigmatic sigma 1 receptors in lipid raft modeling by sigma 1 receptor-mediated cholesterol alteration of lipid rafts in breast cancer cell lines. Cholesterol binds to cholesterol recognition domains in the COOH terminus of the sigma 1 receptor. This binding is blocked by sigma receptor drugs because the cholesterol-binding domains form part of the sigma receptor drug-binding site, mutations of which abolish cholesterol binding. Furthermore, we outline a hypothetical functional model to explain the myriad of biological processes, including cancer, in which these mysterious receptors are involved. The findings of this study provide a biological basis for the potential therapeutic applications of lipid raft cholesterol regulation in cancer therapy using sigma receptor drugs.
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Affiliation(s)
- Christopher P Palmer
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College, London, United Kingdom
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13
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Senior IJ, Hollomon DW, Loeffler RST, Baldwin BC. Sterol composition and resistance to DMI fungicides inErysiphe graminis. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780450109] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Oliaro-Bosso S, Ceruti M, Balliano G, Milla P, Rocco F, Viola F. Analogs of squalene and oxidosqualene inhibit oxidosqualene cyclase of Trypanosoma cruzi expressed in Saccharomyces cerevisiae. Lipids 2005; 40:1257-62. [PMID: 16477810 DOI: 10.1007/s11745-005-1493-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recently, a number of inhibitors of the enzyme oxidosqualene cyclase (OSC; EC 5.4.99.7), a key enzyme in sterol biosynthesis, were shown to inhibit in mammalian cells the multiplication of Trypanosoma cruzi, the parasite agent of Chagas' disease. The gene coding for the OSC of T. cruzi has been cloned and expressed in Saccharomyces cerevisiae. The expression in yeast cells could be a safe and easy model for studying the activity and the selectivity of the potential inhibitors of T. cruzi OSC. Using a homogenate of S. cerevisiae cells expressing T. cruzi OSC, we have tested 19 inhibitors: aza, methylidene, vinyl sulfide, and conjugated vinyl sulfide derivatives of oxidosqualene and squalene, selected as representative of different classes of substrate analog inhibitors of OSC. The IC50 values of inhibition (the compound concentration at which the enzyme is inhibited by 50%) are compared with the values obtained using OSC of pig liver and S. cerevisiae. Many inhibitors of pig liver and S. cerevisiae OSC show comparable IC50 for T. cruzi OSC, but some phenylthiovinyl derivatives are 10-100 times more effective on the T. cruzi enzyme than on the pig or S. cerevisiae enzymes. The expression of proteins of pathogenic organisms in yeast seems very promising for preliminary screening of compounds that have potential therapeutic activity.
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Affiliation(s)
- Simonetta Oliaro-Bosso
- Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, 10125 Turin, Italy
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Vanden Bossche H, Engelen M, Rochette F. Antifungal agents of use in animal health--chemical, biochemical and pharmacological aspects. J Vet Pharmacol Ther 2003; 26:5-29. [PMID: 12603774 DOI: 10.1046/j.1365-2885.2003.00456.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A limited number of antifungal agents is licensed for use in animals, however, many of those available for the treatment of mycoses in humans are used by veterinary practitioners. This review includes chemical aspects, spectra of activity, mechanisms of action and resistance, adverse reactions and drug interactions of the antifungals in current use.
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16
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Abstract
The chemical control of plant pathogens concerns mainly fungal diseases of crops. Most of the available fungicides act directly on essential fungal functions such as respiration, sterol biosynthesis or cell division. Consequently, these compounds can exhibit undesirable toxicological and environmental effects and sometimes select fungal resistant strains. Plant activators are expected to provide sustainable disease management in several crops because the development of resistance is not expected. Considering the future, the discovery of novel antifungal molecules will reap advantage from throughput screening methodologies and functional genomics.
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Affiliation(s)
- Pierre Leroux
- Unité de phytopharmacie et médiateurs chimiques, Inra, route de Saint-Cyr, 78026 Versailles, France.
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17
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Abstract
Pneumocystis lacks ergosterol, and several antimycotics that bind ergosterol in fungal membranes or inhibit its synthesis are ineffective against Pneumocystis pneumonia. The organism synthesizes C(28) and C(29) Delta(7) 24-alkylsterols, 24-alkyllanosterol derivatives, and Delta(5) 24-alkylsterols, which may be produced by modifying scavenged Delta(5) sterols. Mammals cannot desaturate C-22 and alkylate C-24 of sterols, thus, these processes are particularly attractive targets for antifungal drug development. Recent data indicate that C-22 desaturation is not, but C-24 alkylation is an attractive target in P. carinii. The P. carinii S-adenosyl-L-methionine:sterol C-24 methyl transferase (SAM:SMT) has unique properties; it prefers lanosterol as its sterol substrate.
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Affiliation(s)
- Edna S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, OH 45221, USA.
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18
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Joubert BM, Nguyen LN, Matsuda SP, Buckner FS. Cloning and functional characterization of a Trypanosoma brucei lanosterol 14alpha-demethylase gene. Mol Biochem Parasitol 2001; 117:115-7. [PMID: 11551639 DOI: 10.1016/s0166-6851(01)00337-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- B M Joubert
- Department of Chemistry and Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
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19
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Joubert BM, Buckner FS, Matsuda SP. Trypanosome and animal lanosterol synthases use different catalytic motifs. Org Lett 2001; 3:1957-60. [PMID: 11405754 DOI: 10.1021/ol0160506] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[see reaction]. Animals, fungi, and some protozoa convert oxidosqualene to lanosterol in the ring-forming reaction in sterol biosynthesis. The Trypanosoma cruzi lanosterol synthase has now been cloned. The sequence shares with the T. brucei lanosterol synthase a tyrosine substitution for the catalytically important active-site threonine found in animal and fungal lanosterol synthases.
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Affiliation(s)
- B M Joubert
- Department of Chemistry, Rice University, 6100 South Main Street, Houston, Texas 77005, USA
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20
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Leber R, Zenz R, Schröttner K, Fuchsbichler S, Pühringer B, Turnowsky F. A novel sequence element is involved in the transcriptional regulation of expression of the ERG1 (squalene epoxidase) gene in Saccharomyces cerevisiae. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:914-24. [PMID: 11179957 DOI: 10.1046/j.1432-1327.2001.01940.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Squalene epoxidase is an essential enzyme in the ergosterol-biosynthesis pathway. It catalyzes the epoxidation of squalene to 2,3-oxidosqualene and is the specific target of the antifungal drug terbinafine. Treatment of yeast cells with this inhibitor leads to squalene accumulation and sterol depletion. As ergosterol fulfils several essential functions, each requiring optimal sterol concentrations, synthesis of sterols in yeast must be tightly regulated. This study focuses on the sterol-mediated regulation of expression of the ERG1 gene, which codes for squalene epoxidase in Saccharomyces cerevisiae. Inhibition of ergosterol biosynthesis with terbinafine increases the expression of ERG1 in a concentration-dependent manner to a maximum of sevenfold. Inhibition of later steps in the ergosterol-biosynthetic pathway by ketoconazole, an inhibitor of the lanosterol-14alpha-demethylase, and U18666A, an inhibitor of the squalene-2,3-epoxide-lanosterol cyclase, also induce expression of ERG1, suggesting that ERG1 expression is positively regulated by diminished intracellular ergosterol levels. The regulatory effect of sterols is manifested at the level of transcription. Deletion analysis of the ERG1 promoter identified a novel regulatory DNA sequence element. Two 6-bp direct repeats, separated by 4 bp, AGCTCGGCCGAGCTCG, are unique to the ERG1 promoter. A DNA fragment containing this region confers ergosterol-regulated expression on an otherwise unregulated CYC1 promoter construction. One copy of the 6-bp element, AGCTCG, is sufficient to confer regulation, albeit less effectively than when both elements are present, whereas the removal of both elements from the ERG1 promoter leads to the loss of sterol-dependent ERG1 regulation.
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Affiliation(s)
- R Leber
- Institut für Molekularbiologie, Biochemie und Mikrobiologie, Karl-Franzens-Universität Graz, Austria
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21
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Muchembled J, Sahraoui ALH, Grandmougin-Ferjani A, Sancholle M. Changes in sterol composition with ontogeny of Blumeria graminis conidia. ACTA ACUST UNITED AC 2000. [DOI: 10.1139/b00-106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The total sterol composition of conidia of the obligate plant pathogen Blumeria (= Erysiphe) graminis f.sp. tritici has been analysed as a function of their ontogeny during sporulation. Two main classes of sterols were characterized: 24-ethylsterols (24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol) and 24-methylsterols (24-methylenecholesterol and episterol). Our results show that sterol composition is greatly modified during ontogeny of B. graminis conidia both at the qualitative and quantitative levels. In particular, 24-methylsterols, e.g., 24-methylenecholesterol and episterol, are the major sterols in old conidia whereas 24-ethylsterols, e.g., 24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol, are the main sterols in young conidia.Key words: Erysiphe, wheat powdery mildew, sterols, ontogeny.
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22
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Kaneshiro ES, Wyder MA. C27 to C32 sterols found in Pneumocystis, an opportunistic pathogen of immunocompromised mammals. Lipids 2000; 35:317-24. [PMID: 10783009 DOI: 10.1007/s11745-000-0528-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Pneumocystis carinii is the paradigm of opportunistic infections in immunocompromised mammals. Prior to the acquired immunodeficiency syndrome (AIDS) pandemic and the use of immunosuppressive therapy in organ transplant and cancer patients, P. carinii was regarded as a curiosity, rarely observed clinically. Interest in this organism exploded when it was identified as the agent of P. carinii pneumonia (PcP), the direct cause of death among many AIDS patients. Aggressive prophylaxis has decreased the number of acute PcP cases, but it remains among the most prevalent opportunistic infections found within this patient population. The taxonomic assignment of P. carinii has long been argued; molecular genetics data now demonstrate that it is a fungus. Several antimycotic drugs are targeted against ergosterol or its biosynthesis, but these are not as effective against PcP as they are against other fungal infections. This can now be explained in part by the identification of the sterols of P. carinii. The organism lacks ergosterol but contains distinct C28 and C29 delta7 24-alkylsterols. Also, 24-methylenelanost-8-en-3beta-ol (C31) and pneumocysterol, (24Z)-ethylidenelanost-8-en-3beta-ol (C32) were recently identified in organisms infecting humans. Together, the delta7 24-alkylsterols and pneumocysterol are regarded as signature lipids of the pathogen that can be useful for the diagnosis of PcP, since no other lung pathogen is known to contain them. Cholesterol (C27), the dominant sterol component in P. carinii, is probably totally scavenged from the host. De novo synthesis of sterols has been demonstrated by the presence of lovastatin-sensitive 3-hydroxy-3-methylglutaryl-CoA reductase activity, the incorporation of radiolabeled mevalonate and squalene into P. carinii sterols, and the reduction in cellular ATP in cells treated with inhibitors of enzymes in sterol biosynthesis.
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Affiliation(s)
- E S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, Ohio 45221-0006, USA.
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23
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Cotrim PC, Garrity LK, Beverley SM. Isolation of genes mediating resistance to inhibitors of nucleoside and ergosterol metabolism in Leishmania by overexpression/selection. J Biol Chem 1999; 274:37723-30. [PMID: 10608831 DOI: 10.1074/jbc.274.53.37723] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We tested a general method for the identification of drug resistance loci in the trypanosomatid protozoan parasite Leishmania major. Genomic libraries in a multicopy episomal cosmid vector were transfected into susceptible parasites, and drug selections of these transfectant libraries yielded parasites bearing cosmids mediating resistance. Tests with two antifolates led to the recovery of cosmids encoding DHFR-TS or PTR1, two known resistance genes. Overexpression/selection using the toxic nucleoside tubercidin similarly yielded the TOR (toxic nucleoside resistance) locus, as well as a new locus (TUB2) conferring collateral hypersensitivity to allopurinol. Leishmania synthesize ergosterol rather than cholesterol, making this pathway attractive as a chemotherapeutic target. Overexpression/selection using the sterol synthesis inhibitors terbinafine (TBF, targeting squalene epoxidase) and itraconazole (ITZ, targeting lanosterol C(14)-demethylase) yielded nine new resistance loci. Several conferred resistance to both drugs; several were drug-specific, and two TBF-resistant cosmids induced hypersensitivity to ITZ. One TBF-resistant cosmid encoded squalene synthase (SQS1), which is located upstream of the sites of TBF and ITZ action in the ergosterol biosynthetic pathway. This suggests that resistance to "downstream" inhibitors can be mediated by increased expression of ergosterol biosynthetic intermediates. Our studies establish the feasibility of overexpression/selection in parasites and suggest that many Leishmania drug resistance loci are amenable to identification in this manner.
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Affiliation(s)
- P C Cotrim
- Department of Molecular Microbiology, Washington University Medical School, St. Louis, Missouri 63110, USA
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Bargar TM, Secor J, Markley LD, Shaw BA, Erickson JA. A comparative molecular field analysis study of obtusifoliol 14α-methyl demethylase inhibitors. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-9063(199911)55:11<1059::aid-ps57>3.0.co;2-j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Comprehensive evaluation of isoprenoid biosynthesis regulation in Saccharomyces cerevisiae utilizing the Genome Reporter Matrix™. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32120-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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26
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Engels AJG, De Waard MA. Sterol composition of isolates ofErysiphe graminisf.sp.triticidiffering in sensitivity to fenpropimorph. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-9063(199803)52:3<258::aid-ps694>3.0.co;2-f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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27
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Marcireau C, Joets J, Pousset D, Guilloton M, Karst F. FEN2: A gene implicated in the catabolite repression-mediated regulation of ergosterol biosynthesis in yeast. Yeast 1998. [DOI: 10.1002/(sici)1097-0061(199605)12:6<531::aid-yea934>3.0.co;2-e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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28
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Abstract
The genome sequence of Mycobacterium tuberculosis (and also M. leprae) revealed a significant number of homologies to Saccharomyces cerevisiae sterol biosynthetic enzymes. We addressed the hypothesis of a potential sterol biosynthetic pathway existing in Mycobacterium using cultures of Mycobacterum smegmatis. Non-saponifiable lipid extracts subjected to analysis by gas chromatography-mass spectrometry (GC-MS) showed cholesterol was present. Sterol synthesis by M. smegmatis was confirmed using 14C-radiolabelled mevalonic acid and incorporation into C4-desmethyl sterol co-migrating with authentic cholesterol on TLC. The sterol biosynthetic pathway has provided a rich source of targets for commercially important bioactive molecules and such agents represent new opportunities for Mycobacteria chemotherapy.
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Affiliation(s)
- D C Lamb
- Institute of Biological Sciences, University of Wales Aberystwyth, UK
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29
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Silve S, Dupuy PH, Ferrara P, Loison G. Human lamin B receptor exhibits sterol C14-reductase activity in Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1392:233-44. [PMID: 9630650 DOI: 10.1016/s0005-2760(98)00041-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lamin B receptor (LBR), a nuclear protein of avian and mammalian cells, contains an hydrophobic domain that shares extensive structural similarities with the members of the sterol reductase family. To test if the sterol-reductase-like domain of LBR could be enzymatically competent, several sterol reductase-defective strains of Saccharomyces cerevisiae were transformed with a human-LBR expressing vector. LBR production did not change the ergosterol biosynthesis defect in an erg4 mutant impaired in sterol C24(28) reductase. In contrast, the sterol C14 reduction step and ergosterol prototrophy were restored in LBR-producing erg24 transformants which lack endogenous sterol C14 reductase. To test the effects of C14 reductase inhibitors on LBR activity, we constructed EMY54, an ergosterol-requiring strain that is devoid of both sterol C8-C7 isomerase and sterol C14 reductase activities. EMY54 cells recovered the capability of synthesizing ergost-8-en-3beta-ol upon transformation with a vector that expressed either yeast sterol C14 reductase or hLBR. In addition, growth in sterol-free medium was restored in these transformants. Sterol biosynthesis and proliferation of LBR-producing cells were found to be highly susceptible to fenpropimorph and tridemorph, but only moderately susceptible to SR 31747. Our results strongly suggest that hLBR is a sterol C14 reductase.
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Affiliation(s)
- S Silve
- Department of Microbiology, Sanofi-Recherche, Labège Innopole, BP137, F-31676 Labège Cédex, France
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30
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Moebius FF, Fitzky BU, Lee JN, Paik YK, Glossmann H. Molecular cloning and expression of the human delta7-sterol reductase. Proc Natl Acad Sci U S A 1998; 95:1899-902. [PMID: 9465114 PMCID: PMC19210 DOI: 10.1073/pnas.95.4.1899] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Inhibitors of the last steps of cholesterol biosynthesis such as AY9944 and BM15766 severely impair brain development. Their molecular target is the Delta7-sterol reductase (EC 1.3.1.21), suspected to be defective in the Smith-Lemli-Opitz syndrome, a frequent inborn disorder of sterol metabolism. Molecular cloning of the cDNA revealed that the human enzyme is a membrane-bound protein with a predicted molecular mass of 55 kDa and six to nine putative transmembrane segments. The protein is structurally related to plant and yeast sterol reductases. In adults the ubiquitously transcribed mRNA is most abundant in adrenal gland, liver, testis, and brain. The Delta7-sterol reductase is the ultimate enzyme of cholesterol biosynthesis in vertebrates and is absent from yeast. Microsomes from Saccharomyces cerevisiae strains heterologously expressing the human cDNA remove the C7-8 double bond in 7-dehydrocholesterol. The conversion to cholesterol depends on NADPH and is potently inhibited by AY9944 (IC50 0.013 microM), BM15766 (IC50 1.2 microM), and triparanol (IC50 14 microM). Our work paves the way to clarify whether a defect in the delta7-sterol reductase gene underlies the Smith-Lemli-Opitz syndrome.
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Affiliation(s)
- F F Moebius
- Institut für Biochemische Pharmakologie, Universität Innsbruck, Peter Mayr Str. 1, A-6020 Innsbruck, Austria
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31
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Beach DH, Chen F, Cushion MT, Macomber RS, Krudy GA, Wyder MA, Kaneshiro ES. Effects of steroidal allenic phosphonic acid derivatives on the parasitic protists Leishmania donovani, Leishmania mexicana mexicana, and Pneumocystis carinii carinii. Antimicrob Agents Chemother 1997; 41:162-8. [PMID: 8980773 PMCID: PMC163678 DOI: 10.1128/aac.41.1.162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Several pathogenic fungi and protozoa are known to have sterols distinct from those of their mammalian hosts. Of particular interest as targets for drug development are the biosyntheses of the sterols of important parasites such as the kinetoplastid flagellates and the AIDS-associated opportunistic protist Pneumocystis carinii. These pathogens synthesize sterols with an alkyl group at C-24, and some have a double bond at C-22 of the side chain. Humans and other mammalian hosts are incapable of C-24 alkylation and C-22 desaturation. In the present study, three steroidal compounds with side chains substituted by phosphonyl-linked groups were synthesized and tested for their effects on Leishmania donovani and L. mexicana mexicana culture growth. The compounds inhibited organism proliferation at concentrations in micrograms per milliliter. The most potent inhibitors of this group of compounds were characterized by two ethyl groups at the phosphate function. Leishmania organisms treated with 17-[2-(diethylphosphonato) ethylidienyl]3-methoxy-19-norpregna-1,3,5-triene exhibited reduced growth after transfer into inhibitor-free medium. Because there are currently no axenic methods available for the continuous subcultivation of P. carinii, the effects of these drugs on this organism were evaluated by two alternative screening methods. The same two diethyl phosphonosteroid compounds that inhibited Leishmania proliferation were also the most active against P. carinii as determined by the potent effect they had on reducing cellular ATP content. Cystic as well as trophic forms responded to the drug treatments, as evaluated by a dual fluorescent staining live-dead assay. Other modifications of steroidal phosphonates may lead to the development of related drugs with increased activity and specificity for the pathogens.
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Affiliation(s)
- D H Beach
- Department of Microbiology and Immunology, State University of New York Health Science Center at Syracuse 13210, USA
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33
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Hauptfleisch R, Franck B. Stereoselective syntheses of 1,24-dihydroxy squalene 2,3;22,23-dioxides by double sharpless epoxidation. Tetrahedron Lett 1997. [DOI: 10.1016/s0040-4039(96)02332-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Moebius FF, Bermoser K, Reiter RJ, Hanner M, Glossmann H. Yeast sterol C8-C7 isomerase: identification and characterization of a high-affinity binding site for enzyme inhibitors. Biochemistry 1996; 35:16871-8. [PMID: 8988026 DOI: 10.1021/bi961996m] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The yeast gene ERG2 encodes a sterol C8-C7 isomerase and is essential for ergosterol synthesis and cell proliferation. Its striking homology with the so-called sigma1 receptor of guinea pig brain, a polyvalent steroid and drug binding protein, suggested that the yeast sterol C8-C7 isomerase (ERG2) carries a similar high affinity drug binding domain. Indeed the sigma ligands [3H]haloperidol (Kd = 0.3 nM) and [3H]ifenprodil (Kd = 1.4 nM) bound to a single population of sites in ERG2 wild type yeast microsomes (Bmax values of 77 and 61 pmol/mg of protein, respectively), whereas binding activity was absent in strains carrying ERG2 gene mutations or disruptions. [3H]Ifenprodil binding was inhibited by sterol isomerase inhibitors such as fenpropimorph (Ki = 0.05 nM), tridemorph (Ki = 0.09 nM), MDL28,815 (Ki = 0.44 nM), triparanol (Ki = 1.5 nM), and AY-9944 (Ki = 5.8 nM). [3H]Haloperidol specifically photoaffinity-labeled a protein with an apparent molecular weight of 27400, in agreement with the molecular mass of the sterol C8-C7 isomerase (24900 Da). 9E10 c-myc antibodies specifically immunoprecipitated the c-myc tagged protein after [3H]haloperidol photolabeling, unequivocally proving that the drug binding site is localized on the ERG2 gene product. Haloperidol, trifluperidol, and ifenprodil inhibited the growth of Saccharomyces cerevisiae and reduced the ergosterol content of cells grown in their presence. Our results demonstrate that the yeast sterol C8-C7 isomerase has a polyvalent high-affinity drug binding site similar to mammalian sigma receptors and that in yeast sigma ligands inhibit sterol biosynthesis.
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Affiliation(s)
- F F Moebius
- Institut für Biochemische Pharmakologie, Universität Innsbruck, Austria
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35
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Hanner M, Moebius FF, Flandorfer A, Knaus HG, Striessnig J, Kempner E, Glossmann H. Purification, molecular cloning, and expression of the mammalian sigma1-binding site. Proc Natl Acad Sci U S A 1996; 93:8072-7. [PMID: 8755605 PMCID: PMC38877 DOI: 10.1073/pnas.93.15.8072] [Citation(s) in RCA: 724] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sigma-ligands comprise several chemically unrelated drugs such as haloperidol, pentazocine, and ditolylguanidine, which bind to a family of low molecular mass proteins in the endoplasmic reticulum. These so-called sigma-receptors are believed to mediate various pharmacological effects of sigma-ligands by as yet unknown mechanisms. Based on their opposite enantioselectivity for benzomorphans and different molecular masses, two subtypes are differentiated. We purified the sigma1-binding site as a single 30-kDa protein from guinea pig liver employing the benzomorphan(+)[3H]pentazocine and the arylazide (-)[3H]azidopamil as specific probes. The purified (+)[3H]pentazocine-binding protein retained its high affinity for haloperidol, pentazocine, and ditolylguanidine. Partial amino acid sequence obtained after trypsinolysis revealed no homology to known proteins. Radiation inactivation of the pentazocine-labeled sigma1-binding site yielded a molecular mass of 24 +/- 2 kDa. The corresponding cDNA was cloned using degenerate oligonucleotides and cDNA library screening. Its open reading frame encoded a 25.3-kDa protein with at least one putative transmembrane segment. The protein expressed in yeast cells transformed with the cDNA showed the pharmacological characteristics of the brain and liver sigma1-binding site. The deduced amino acid sequence was structurally unrelated to known mammalian proteins but it shared homology with fungal proteins involved in sterol synthesis. Northern blots showed high densities of the sigma1-binding site mRNA in sterol-producing tissues. This is also in agreement with the known ability of sigma1-binding sites to interact with steroids, such as progesterone.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding Sites
- Binding, Competitive
- Brain/metabolism
- Chromatography, Affinity
- Chromatography, Ion Exchange
- Cloning, Molecular
- DNA Primers
- DNA, Complementary
- DNA-Binding Proteins/chemistry
- Guinea Pigs
- Intracellular Membranes/metabolism
- Kinetics
- Ligands
- Mammals
- Microsomes/metabolism
- Microsomes, Liver/metabolism
- Molecular Sequence Data
- Pentazocine/metabolism
- Polymerase Chain Reaction
- Receptors, sigma/chemistry
- Receptors, sigma/isolation & purification
- Receptors, sigma/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/isolation & purification
- Saccharomyces cerevisiae
- Sequence Homology, Amino Acid
- Trans-Activators/chemistry
- Transcriptional Regulator ERG
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Affiliation(s)
- M Hanner
- Instit für Biochemische Pharmakologie, Universität Innsbruck, Austria
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36
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Silve S, Leplatois P, Josse A, Dupuy PH, Lanau C, Kaghad M, Dhers C, Picard C, Rahier A, Taton M, Le Fur G, Caput D, Ferrara P, Loison G. The immunosuppressant SR 31747 blocks cell proliferation by inhibiting a steroid isomerase in Saccharomyces cerevisiae. Mol Cell Biol 1996; 16:2719-27. [PMID: 8649379 PMCID: PMC231262 DOI: 10.1128/mcb.16.6.2719] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
SR 31747 is a novel immunosuppressant agent that arrests cell proliferation in the yeast Saccharomyces cerevisiae, SR 31747-treated cells accumulate the same aberrant sterols as those found in a mutant impaired in delta 8- delta 7-sterol isomerase. Sterol isomerase activity is also inhibited by SR 31747 in in vitro assays. Overexpression of the sterol isomerase-encoding gene, ERG2, confers enhanced SR resistance. Cells growing anaerobically on ergosterol-containing medium are not sensitive to SR. Disruption of the sterol isomerase-encoding gene is lethal in cells growing in the absence of exogenous ergosterol, except in SR-resistant mutants lacking either the SUR4 or the FEN1 gene product. The results suggest that sterol isomerase is the target of SR 31747 and that both the SUR4 and FEN1 gene products are required to mediate the proliferation arrest induced by ergosterol depletion.
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Affiliation(s)
- S Silve
- Department of Microbiology, Sanofi-Recherche, Labège, France
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37
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Marcireau C, Joets J, Pousset D, Guilloton M, Karst F. FEN2: a gene implicated in the catabolite repression-mediated regulation of ergosterol biosynthesis in yeast. Yeast 1996; 12:531-9. [PMID: 8771708 DOI: 10.1002/(sici)1097-0061(199605)12:6%3c531::aid-yea934%3e3.0.co;2-e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have isolated and characterized a pleiotropic recessive mutation. fen2-1, that causes resistance to fenpropimorph and a low level of ergosterol in Saccharomyces cerevisiae. Ergosterol synthesis in the mutant strain was 5.5-fold slower than in the wild type; however, in vitro assays of the enzymes involved in ergosterol biosynthesis could not account for this low rate in the mutant. The mutant phenotype was expressed only in media exerting both carbon and nitrogen catabolite repression. To our knowledge, this is the first locus in yeast that reveals a concerted regulation between different pathways (carbon and nitrogen catabolite repression and/or general control of amino acid biosynthesis and ergosterol biosynthesis). The yeast gene FEN2 has been isolated and contains an open reading frame (ORF) of 512 codons. This ORF was found to be identical to YCR28C of chromosome III. A possible function of the FEN2 gene product in yeast is discussed.
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Affiliation(s)
- C Marcireau
- Laboratoire de Génétique Physiologique et Moléculaire, Université de Poitiers, France
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38
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Georgopapadakou NH, Walsh TJ. Antifungal agents: chemotherapeutic targets and immunologic strategies. Antimicrob Agents Chemother 1996; 40:279-91. [PMID: 8834867 PMCID: PMC163103 DOI: 10.1128/aac.40.2.279] [Citation(s) in RCA: 330] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- N H Georgopapadakou
- Department of Oncology, Roche Research Center, Nutley, New Jersey 07110, USA
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39
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Fenner GP, Raphiou I. Growth of Cucurbita maxima L. plants in the presence of the cycloartenol synthase inhibitor U18666A. Lipids 1995; 30:253-6. [PMID: 7791534 DOI: 10.1007/bf02537829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Squash, like other Cucurbitaceae, have unique sterol profiles that offer an excellent opportunity to examine the relationship between sterol biosynthesis and plant growth. To determine the effect of sterol biosynthesis inhibition on squash growth, Cucurbita maxima seedlings with and without cotyledons were subjected to increasing concentrations of the cycloarternol synthase (EC 5.4.99.8) inhibitor 3 beta-(2-diethylaminoethoxy)androstenone (U18666A). Inhibition of shoot growth was concentration-dependent (from 0, 2, 5, 10, and 20 microM); plants with intact cotyledons grew to 26.4, 23.7, 21.6, 20.0, and 15.6 cm, respectively, at the above inhibitor concentrations, compared to 25.5, 19.4, 17.0, 12.0, and 11 cm for plants with severed cotyledons. In plants with severed cotyledons, 10 and 20 microM U18666A caused rapid necrosis of the first two, newly emerged, primary leaves, and halted new leaf formation. Secondary root formation was initially affected at all inhibitor concentrations regardless of whether cotyledons were present or not. Vegetative tissue showed a decrease in the accumulation of the major squash sterol, 7,22-stigmastadienol, accompanied by increased accumulation of minor sterol components. Sterol profiles in cotyledons were unaltered. The data show that sterols are crucial for maintaining plant growth and viability, but do not address the cotyledonary effect on growth with respect to sterol biosynthesis.
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Affiliation(s)
- G P Fenner
- Crop Science Department, North Carolina State University, Raleigh 27695, USA
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Keon JP, James CS, Court S, Baden-Daintree C, Bailey AM, Burden RS, Bard M, Hargreaves JA. Isolation of the ERG2 gene, encoding sterol delta 8-->delta 7 isomerase, from the rice blast fungus Magnaporthe grisea and its expression in the maize smut pathogen Ustilago maydis. Curr Genet 1994; 25:531-7. [PMID: 8082205 DOI: 10.1007/bf00351674] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Magnaporthe grisea ERG2 gene, encoding delta 8-->delta 7 sterol isomerase, was isolated from a genomic library by heterologous hybridization to a fragment of the Ustilago maydis ERG2 gene. The isolated gene contained a reading frame of 745 bp which encoded a protein of 221 amino acids. The coding region was interrupted by a single putative 79-bp-long intron. The deduced amino-acid sequence exhibited similarity to the ERG2 gene products of U. maydis and of Saccharomyces cerevisiae, particularly in the central region of the proteins. The NH2-terminal of all three proteins contained a long stretch of amino acids that were strongly hydrophobic, suggesting that they may function by anchoring the protein to a membrane surface. The M. grisea ERG2 gene complemented a U. maydis deletion mutant in which the ERG2 gene had been removed using a one-step gene replacement procedure. The delta 8-->delta 7 sterol isomerase produced by the M. grisea ERG2 gene exhibited a level of sensitivity to the sterol biosynthesis inhibitor, tridemorph, similar to that of the enzyme derived from the U. maydis ERG2 gene.
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Affiliation(s)
- J P Keon
- Department of Agricultural Sciences, University of Bristol, Long Ashton Research Station, UK
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Kirsch DR. Development of improved cell-based assays and screens in Saccharomyces through the combination of molecular and classical genetics. Curr Opin Biotechnol 1993; 4:543-52. [PMID: 7764204 DOI: 10.1016/0958-1669(93)90075-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Traditionally, the discovery of pharmaceutical and agrochemical products has largely depended on mass screening. Over the years, screen design and screening programs have evolved in terms of the sensitivity with which active material can be identified, the number of samples that can be tested, and the types of molecular targets and cellular functions that can be conveniently assayed. More recently, screens with desirable properties have been developed for a great variety of molecular targets through the exploitation of Saccharomyces molecular biology and genetics. Recent advances have enabled researchers to develop yeast-based screens for agents acting on a number of new therapeutic targets: G-protein linked receptors, cytoplasmic receptors, ion (potassium) channels, novel fungal cell wall enzymes, fungal sterol biosynthesis enzymes, antiviral targets, immunosuppressive targets, cyclic nucleotide phosphodiesterase, oncogenes and the multiple drug resistance (MDR) protein.
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Affiliation(s)
- D R Kirsch
- American Cynamid, Molecular Genetic Screen Design, Princeton, New Jersey 08543-0400
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Casey WM, Keesler GA, Parks LW. Regulation of partitioned sterol biosynthesis in Saccharomyces cerevisiae. J Bacteriol 1992; 174:7283-8. [PMID: 1429452 PMCID: PMC207422 DOI: 10.1128/jb.174.22.7283-7288.1992] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Using yeast strains with null mutations in structural genes which encode delta-aminolevulinic acid synthetase (HEM1), isozymes of 3-hydroxy-3-methylglutaryl coenzyme A (HMG1 and HMG2), squalene epoxidase (ERG1), and fatty acid delta 9-desaturase (OLE1), we were able to determine the effect of hemes, sterols, and unsaturated fatty acids on both sterol production and the specific activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) in Saccharomyces cerevisiae. We found that the HMGR isozymes direct essentially equal amounts of carbon to the biosynthesis of sterols under heme-competent conditions, despite a huge disparity (57-fold) in the specific activities of the reductases. Our results demonstrate that palmitoleic acid (16:1) acts as a rate-limiting positive regulator and that ergosterol acts as a potent inhibitor of sterol production in strains which possess only the HMGR1 isozyme (HMG1 hmg2). In strains which contain only the HMGR2 isozyme (hmg1 HMG2), sterol production was inhibited by oleic acid (18:1) and to a lesser degree by ergosterol. The specific activities of the two reductases (HMGR1 and HMGR2) were found to be differentially regulated by hemes but not by ergosterol, palmitoleic acid, or oleic acid. The disparate effects of unsaturated fatty acids and sterols on these strains lead us to consider the possibility of separate, compartmentalized isoprenoid pathways in S. cerevisiae.
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Affiliation(s)
- W M Casey
- Department of Microbiology, North Carolina State University, Raleigh 27695
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