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Tohoyama H, Shiraishi E, Amano S, Inouhe M, Joho M, Murayama T. Amplification of a gene for metallothionein by tandem repeat in a strain of cadmium-resistant yeast cells. FEMS Microbiol Lett 1996. [DOI: 10.1111/j.1574-6968.1996.tb08060.x] [Citation(s) in RCA: 7] [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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2
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Tohoyama H, Inouhe M, Joho M, Murayama T. Production of metallothionein in copper- and cadmium-resistant strains of Saccharomyces cerevisiae. JOURNAL OF INDUSTRIAL MICROBIOLOGY 1995; 14:126-31. [PMID: 7766204 DOI: 10.1007/bf01569894] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Certain mutants of the yeast Saccharomyces cerevisiae show copper or cadmium resistance. Both copper- and cadmium-resistant strains produce the same metallothionein with 53 amino acid residues which causes metal detoxification by chelating copper or cadmium. The metal detoxification role is the only known function of the metallothionein in yeast. The MT is encoded by the CUP1 gene on chromosome VIII which is expressed by induction with metals. The CUP1 is amplified to 3-14 copies with 2 kb-tandem-repeat units in the metal-resistant strains, whereas the wild-type strain contains only a single copy of the CUP1. Although transcription of CUP1 is inducible by metals, the ACE1 protein serves a dual function as a sensor for copper and an inducer for CUP1 transcription in the copper-resistant strain. In the cadmium-resistant strain, the heat-shock factor having a point mutation may be the regulator for CUP1 transcription. Therefore, it has been clarified that production of MT in yeast is controlled by two systems, the amplification of CUP1 and its transcriptional regulation.
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Affiliation(s)
- H Tohoyama
- Department of Biology, Faculty of Science, Ehime University, Japan
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3
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Dorsey MJ, Hoeh P, Paquin CE. Phenotypic identification of amplifications of the ADH4 and CUP1 genes of Saccharomyces cerevisiae. Curr Genet 1993; 23:392-6. [PMID: 8319294 DOI: 10.1007/bf00312624] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Primary gene amplification, i.e., mutation from one gene copy to multiple gene copies per genome, is important in genomic evolution, as a means of producing anti-cancer drug resistance, and is associated with the progression of tumor malignancy. Primary amplification has not been studied in normal eukaryotic cells because amplifications are extremely rare in these cells. A system has been developed to phenotypically identify co-amplifications of the ADH4 and CUP1 genes of Saccharomyces cerevisiae and 21 independent spontaneous amplifications have been isolated.
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Affiliation(s)
- M J Dorsey
- Department of Biological Sciences, University of Cincinnati, OH 45221-0006
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4
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Binding of a sequence-specific single-stranded DNA-binding factor to the simian virus 40 core origin inverted repeat domain is cell cycle regulated. Mol Cell Biol 1993. [PMID: 8380226 DOI: 10.1128/mcb.13.1.408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The inverted repeat domain (IR domain) within the simian virus 40 origin of replication is the site of initial DNA melting prior to the onset of DNA synthesis. The domain had previously been shown to be bound by a cellular factor in response to DNA damage. We demonstrate that two distinct cellular components bind opposite strands of the IR domain. Replication protein A (RPA), previously identified as a single-stranded DNA binding protein required for origin-specific DNA replication in vitro, is shown to have a preference for the pyrimidine-rich strand. A newly described component, IR factor B (IRF-B), specifically recognizes the opposite strand. IRF-B binding activity in nuclear extract varies significantly with cell proliferation and the cell cycle, so that binding of IRF-B to the IR domain is negatively correlated with the onset of DNA synthesis. Loss of IRF-B binding from the nucleus also occurs in response to cellular DNA damage. UV cross-linking indicates that the core binding component of IRF-B is a protein of ca. 34 kDa. We propose that RPA and IRF-B bind opposite strands of the IR domain and together may function in the regulation of origin activation.
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Carmichael EP, Roome JM, Wahl AF. Binding of a sequence-specific single-stranded DNA-binding factor to the simian virus 40 core origin inverted repeat domain is cell cycle regulated. Mol Cell Biol 1993; 13:408-20. [PMID: 8380226 PMCID: PMC358921 DOI: 10.1128/mcb.13.1.408-420.1993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The inverted repeat domain (IR domain) within the simian virus 40 origin of replication is the site of initial DNA melting prior to the onset of DNA synthesis. The domain had previously been shown to be bound by a cellular factor in response to DNA damage. We demonstrate that two distinct cellular components bind opposite strands of the IR domain. Replication protein A (RPA), previously identified as a single-stranded DNA binding protein required for origin-specific DNA replication in vitro, is shown to have a preference for the pyrimidine-rich strand. A newly described component, IR factor B (IRF-B), specifically recognizes the opposite strand. IRF-B binding activity in nuclear extract varies significantly with cell proliferation and the cell cycle, so that binding of IRF-B to the IR domain is negatively correlated with the onset of DNA synthesis. Loss of IRF-B binding from the nucleus also occurs in response to cellular DNA damage. UV cross-linking indicates that the core binding component of IRF-B is a protein of ca. 34 kDa. We propose that RPA and IRF-B bind opposite strands of the IR domain and together may function in the regulation of origin activation.
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Affiliation(s)
- E P Carmichael
- Department of Cellular and Molecular Biology, Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, Connecticut 06492
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6
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Naumov GI, Naumova ES, Turakainen H, Korhola M. A new family of polymorphic metallothionein-encoding genes MTH1 (CUP1) and MTH2 in Saccharomyces cerevisiae. Gene 1992; 119:65-74. [PMID: 1327961 DOI: 10.1016/0378-1119(92)90067-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
By pulsed-field gel electrophoresis of chromosomal DNA and hybridization with a cloned MTH1 (CUP1) gene, we determined the locations of metallothionein-encoding gene sequences on chromosomes in monosporic cultures of 76 natural strains of Saccharomyces cerevisiae. Most of the strains (68) exhibited a previously known location for the MTH sequence on chromosome (chr.) VIII. Seven strains (resistant or sensitive to Cu2+) showed a MTH sequence in a new locus, MTH2, on chr. XVI. One strain carried an MTH locus on both chromosomes VIII and XVI. Restriction fragment and Southern blot analyses showed that the two MTH loci were very closely related. The strains displayed heterogeneity in the size and structure of their MTH2 locus. The length of the repeat unit of MTH2 varied: a 1.9-kb or 1.7-kb unit was found, instead of the 2.0-kb unit of the MTH1 locus. The most resistant strain (resistant to 1.2 mM CuSO4) contained a 0.9-kb repeat unit in addition to those of 1.9 kb and 1.7 kb. All three sensitive (to over 0.3 mM CuSO4) strains with an mth2 locus had a repeat unit of 1.9 kb or 1.7 kb, suggesting the presence of at least two copies of the MTH2 gene, with one always being in the junction area outside of the repeat unit. A monogenic tetrad segregation of 2:2 was usually found in crosses of resistant MTH2 and sensitive mth2 strains. Hybrids between strains with different MTH loci in all combinations showed low ascospore viability, suggesting that the complete lack of an MTH locus may lead to the death of segregants on YPD medium. The MTH1 and MTH2 loci were exchangeable. Strains with a high level of Cu2+ resistance were also resistant to Cd2+. However, these two properties did not cosegregate in heterozygotic hybrids.
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Affiliation(s)
- G I Naumov
- Scientific Research Institute for Genetics and Selection of Industrial Microorganisms, Moscow, Russia
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7
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Tohoyama H, Inagawa A, Koike H, Inouhe M, Joho M, Murayama T. Constitutive transcription of the gene for metallothionein in a cadmium-resistant yeast. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05346.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Aladjem MI, Lavi S. The mechanism of carcinogen-induced DNA amplification: in vivo and in vitro studies. Mutat Res 1992; 276:339-44. [PMID: 1374526 DOI: 10.1016/0165-1110(92)90020-a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Exposure to chemical carcinogens provides a means for the enhancement of the frequency of gene amplification and for the facilitation of research into its mechanism(s). Using carcinogen-induced SV40 amplification as a model system it was shown that amplification of the viral sequences occurs via a replication-dependent mode. This process involves overactivation of the origin region and the generation of inverted repeats. Carcinogen-induced enhancement of gene amplification is triggered by cellular factors that could act in trans. An in vitro amplification system, based on extracts from carcinogen-treated cells and SV40 template sequences, was used to further characterize the amplification intermediates. The major products of overreplication in this system consist of sequences derived from the origin region. Our studies suggest that the ability to overreplicate the origin region in vitro derives from the combined action of carcinogen-induced factors that trigger overinitiation, with the inherent inability of Chinese hamster cell extracts to fully replicate large plasmid templates. The newly replicated sequences are not associated with the parental molecule and contain hairpin or stem and loop structures. Based on these findings we propose a novel replicative mechanism for DNA amplification that allows the de novo formation of hairpin structures. According to this model, an obstruction of the replication fork may cause an overturning of the DNA polymerase, followed by a template switch that leads to the use of the newly replicated strand as a template. This mode of replication results in the generation of hairpin structures which can function as precursors for the duplicated inverted repeats which are commonly observed in amplified genomes. This model is supported by our in vitro and in vivo studies. The relevance of this model for the amplification of cellular sequences is discussed.
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Affiliation(s)
- M I Aladjem
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
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Tohoyama H, Tomoyasu T, Inouhe M, Joho M, Murayama T. The gene for cadmium metallothionein from a cadmium-resistant yeast appears to be identical to CUP1 in a copper-resistant strain. Curr Genet 1992; 21:275-80. [PMID: 1525854 DOI: 10.1007/bf00351682] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A cadmium-resistant strain of Saccharomyces cerevisiae produces a cadmium metallothionein with the same characteristics as the copper metallothionein that is encoded by CUP1 in a copper-resistant strain. The structural gene for metallothionein from the cadmium-resistant strain resembles CUP1 in terms of the fragmentation patterns generated by restriction enzymes. Furthermore, the gene may be amplified as 2.0 kb repeating units in both the cadmium-resistant and the copper-resistant strains. However, transformants with a plasmid that carried the metallothionein gene from the cadmium-resistant strain were resistant to copper but not to cadmium. It appears that the same metallothionein gene, CUP1, is amplified in both cadmium- and copper-resistant yeasts. However, the mechanism for the cadmium-specific inducibility of the gene may be restricted to the cadmium-resistant strain.
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Affiliation(s)
- H Tohoyama
- Department of Biology, Faculty of Science, Ehime University, Matsuyama, Japan
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Cano-Canchola C, Sosa L, Fonzi W, Sypherd P, Ruiz-Herrera J. Developmental regulation of CUP gene expression through DNA methylation in Mucor spp. J Bacteriol 1992; 174:362-6. [PMID: 1729231 PMCID: PMC205725 DOI: 10.1128/jb.174.2.362-366.1992] [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: 12/28/2022] Open
Abstract
Inserts which carried the CUP gene from Saccharomyces cerevisiae or Mucor racemosus were used as hybridization probes to measure the methylation state and expression of the CUP gene from Mucor rouxii at different stages of growth. It was observed that the fungus contains a CUP multigene family. All the CUP genes were present in a hypermethylated DNA region in nongrowing and isodiametrically growing spores and were not transcribed at these stages. After germ tube emergence, CUP genes became demethylated and transcriptionally active. Development, demethylation, and transcription of CUP genes were blocked by the ornithine decarboxylase inhibitor 1,4-diaminobutanone. These results suggest that genes that are activated during development became demethylated in this fungus.
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Affiliation(s)
- C Cano-Canchola
- Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Mexico
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Mehra RK, Winge DR. Metal ion resistance in fungi: molecular mechanisms and their regulated expression. J Cell Biochem 1991; 45:30-40. [PMID: 2005182 DOI: 10.1002/jcb.240450109] [Citation(s) in RCA: 154] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
One stress response in cells is the ability to survive in an environment containing excessive concentrations of metal ions. This paper reviews current knowledge about cellular and molecular mechanisms involved in the response and adaptation of various fungal species to metal stress. Most cells contain a repertoire of mechanisms to maintain metal homeostasis and prevent metal toxicity. Roles played by glutathione, related (gamma-EC)nG peptides, metallothionein-like polypeptides, and sulfide ions are discussed. In response to cellular metal stress, the biosynthesis of some of these molecules are metalloregulated via intracellular metal sensors. The identify of the metal sensors and the role of metal ions in the regulation of biosynthesis of metallothionein and (gamma-EC)nG peptides are subjects of much current attention and are discussed herein.
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Affiliation(s)
- R K Mehra
- Department of Medicine, University of Utah, Salt Lake City 84132
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Mehra RK, Garey JR, Winge DR. Selective and tandem amplification of a member of the metallothionein gene family in Candida glabrata. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39335-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Fahrig R, Kaspers I. Adaptive resistance of Saccharomyces cerevisiae to chronic treatment with mutagens being due to a dominant mutation. Mutat Res 1990; 228:141-8. [PMID: 2105460 DOI: 10.1016/0027-5107(90)90070-k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The exposure of mammalian cells or tumors for weeks or months to low non-lethal doses of cytostatic drugs may induce multi-drug resistance, which can be enhanced by a variety of DNA-damaging agents. In yeast multi-drug resistance to a variety of drugs has been observed. DNA-damaging agents have not yet been tested. As the appearance of resistance is the result of long-term exposure, we decided to extend the application of test substances to a period of up to 400 days. In such long-term experiments S. cerevisiae MP1 adapted to treatment with low doses of mutagens. Consistent results were obtained for both alkylating and non-alkylating mutagenic substances. Furthermore, the adaptive resistance to the alkylating agent also adapted cells to the non-alkylating agent, which implies that there may be a single pathway for mutagens with different modes of action. Random spore analysis of adapted yeast cells and the back-cross to the parental wild type indicates that a single dominant mutation is responsible for the adaptive resistance.
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Affiliation(s)
- R Fahrig
- Abteilung Genetik, Fraunhofer-Institut für Toxikologie und Aerosolforschung, Hannover, F.R.G
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