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Rodríguez R, Gaivão I, Aguado L, Espina M, García J, Martínez-Camblor P, Sierra LM. The Comet Assay in Drosophila: A Tool to Study Interactions between DNA Repair Systems in DNA Damage Responses In Vivo and Ex Vivo. Cells 2023; 12:1979. [PMID: 37566058 PMCID: PMC10417035 DOI: 10.3390/cells12151979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/26/2023] [Accepted: 07/30/2023] [Indexed: 08/12/2023] Open
Abstract
The comet assay in Drosophila has been used in the last few years to study DNA damage responses (DDR) in different repair-mutant strains and to compare them to analyze DNA repair. We have used this approach to study interactions between DNA repair pathways in vivo. Additionally, we have implemented an ex vivo comet assay, in which nucleoids from treated and untreated cells were incubated ex vivo with cell-free protein extracts from individuals with distinct repair capacities. Four strains were used: wild-type OregonK (OK), nucleotide excision repair mutant mus201, dmPolQ protein mutant mus308, and the double mutant mus201;mus308. Methyl methanesulfonate (MMS) was used as a genotoxic agent. Both approaches were performed with neuroblasts from third-instar larvae; they detected the effects of the NER and dmPolQ pathways on the DDR to MMS and that they act additively in this response. Additionally, the ex vivo approach quantified that mus201, mus308, and the double mutant mus201;mus308 strains presented, respectively, 21.5%, 52.9%, and 14.8% of OK strain activity over MMS-induced damage. Considering the homology between mammals and Drosophila in repair pathways, the detected additive effect might be extrapolated even to humans, demonstrating that Drosophila might be an excellent model to study interactions between repair pathways.
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Affiliation(s)
- Rubén Rodríguez
- Department of Functional Biology (Genetic Area), University of Oviedo, 33006 Oviedo, Spain; (R.R.)
- Oncology University Institute from Asturias (IUOPA), University of Oviedo, 33006 Oviedo, Spain
| | - Isabel Gaivão
- Department of Genetics and Biotechnology and CECAV, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
| | - Leticia Aguado
- Department of Functional Biology (Genetic Area), University of Oviedo, 33006 Oviedo, Spain; (R.R.)
- Oncology University Institute from Asturias (IUOPA), University of Oviedo, 33006 Oviedo, Spain
| | - Marta Espina
- Department of Functional Biology (Genetic Area), University of Oviedo, 33006 Oviedo, Spain; (R.R.)
- Oncology University Institute from Asturias (IUOPA), University of Oviedo, 33006 Oviedo, Spain
| | - Jorge García
- Department of Functional Biology (Genetic Area), University of Oviedo, 33006 Oviedo, Spain; (R.R.)
| | - Pablo Martínez-Camblor
- Department of Biomedical Data Science, Geisel Medical School at Dartmouth, Hanover, NH 03755, USA;
- Faculty of Health Sciences, Universidad Autónoma de Chile, Provedencia 7500912, Chile
| | - L. María Sierra
- Department of Functional Biology (Genetic Area), University of Oviedo, 33006 Oviedo, Spain; (R.R.)
- Oncology University Institute from Asturias (IUOPA), University of Oviedo, 33006 Oviedo, Spain
- Institute of Sanitary Research of the Principality of Asturias, Av. del Hospital Universitario, s/n, 33011 Oviedo, Spain
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2
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Abstract
Nucleotide excision repair (NER) is a highly conserved mechanism to remove helix-distorting DNA lesions. A major substrate for NER is DNA damage caused by environmental genotoxins, most notably ultraviolet radiation. Xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy are three human disorders caused by inherited defects in NER. The symptoms and severity of these diseases vary dramatically, ranging from profound developmental delay to cancer predisposition and accelerated ageing. All three syndromes include developmental abnormalities, indicating an important role for optimal transcription and for NER in protecting against spontaneous DNA damage during embryonic development. Here, we review the current knowledge on genes that function in NER that also affect embryonic development, in particular the development of a fully functional nervous system.
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Affiliation(s)
- Sofia J Araújo
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain.,Institute of Biomedicine, University of Barcelona (IBUB), Barcelona, Spain
| | - Isao Kuraoka
- Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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3
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Gaivão I, Rodríguez R, Sierra LM. Use of the Comet Assay to Study DNA Repair in Drosophila melanogaster. GENOTOXICITY AND DNA REPAIR 2014. [DOI: 10.1007/978-1-4939-1068-7_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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4
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García Sar D, Aguado L, Montes Bayón M, Comendador MA, Blanco González E, Sanz-Medel A, Sierra LM. Relationships between cisplatin-induced adducts and DNA strand-breaks, mutation and recombination in vivo in somatic cells of Drosophila melanogaster, under different conditions of nucleotide excision repair. Mutat Res 2011; 741:81-8. [PMID: 22108251 DOI: 10.1016/j.mrgentox.2011.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 10/27/2011] [Accepted: 11/02/2011] [Indexed: 12/22/2022]
Abstract
Cisplatin is a chemotherapeutic drug widely used in the treatment of several tumours, but this chemotherapy presents problems in terms of side-effects and patient resistance. The detection and determination of cisplatin-induced adducts and the relationship with the physiological or clinical effects of this drug under different repair conditions could be a good measure to assess patient's response to such chemotherapy. A new methodological approach to detect and quantify cisplatin adducts by use of high-performance liquid chromatography with inductively coupled plasma mass-spectrometric detection (HPLC-ICP-MS) and isotope-dilution analysis (IDA), is evaluated for its application in vivo, under different repair conditions. This analysis is combined with the use of the Comet assay, which detects DNA strand-breaks, and the w/w(+) SMART assay, which monitors induction of somatic mutation and recombination in Drosophila melanogaster in vivo under different conditions of nucleotide-excision repair. Results show that (i) cisplatin induces in Drosophila several adducts not detected in mammals. The two most abundant cisplatin-induced adducts, identified by electrospray-mass spectrometry as G monoadduct and G-G intrastrand cross-links, were quantified individually; (ii) cisplatin induces higher levels of G monoadducts and G-G cross-links in NER-proficient than in NER-deficient cells; (iii) the level of adducts correlates with their biological consequences, both in terms of DNA strand-breaks (tail-moment values), and of somatic mutation and recombination (frequency of mosaic eyes and clones in 10(4) cells), when the repair status is considered. This work demonstrates the validity and potential of the adduct detection and quantification methodology in vivo, and its use to correlate adducts with their genetic consequences.
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Affiliation(s)
- Daniel García Sar
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, C/ Julián Clavería 8
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5
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Furukawa T, Imamura T, Kitamoto HK, Shimada H. Rice exonuclease-1 homologue, OsEXO1, that interacts with DNA polymerase lambda and RPA subunit proteins, is involved in cell proliferation. PLANT MOLECULAR BIOLOGY 2008; 66:519-531. [PMID: 18231866 DOI: 10.1007/s11103-008-9288-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 12/31/2007] [Indexed: 05/25/2023]
Abstract
Exonuclease 1, a class III member of the RAD2 nuclease family, is a structure-specific nuclease involved in DNA metabolism (replication, repair and recombination). We have identified a homologue to Exonuclease-1 from rice (Oryza sativa L. cv. Nipponbare) and have designated it O. sativa Exonuclease-1 (OsEXO1). The open reading frame of OsEXO1 encodes a predicted product of 836 amino acid residues with a molecular weight of 92 kDa. Two highly conserved nuclease domains (XPG-N and XPG-I) are present in the N-terminal region of the protein. OsEXO1-sGFP fusion protein transiently overexpressed in the onion epidermal cells localized to the nucleus. The transcript of OsEXO1 is highly expressed in meristematic tissues and panicles. Inhibition of cell proliferation by removal of sucrose from the medium or by the addition of cell cycle inhibitors decreased OsEXO1 expression. Functional complementation assays using yeast RAD2 member null mutants demonstrates that OsEXO1 is able to substitute for ScEXO1 and ScRAD27 functions. Yeast two-hybrid analysis shows that OsEXO1 interacted with rice DNA polymerase lambda (OsPol lambda), the 70 kDa subunit b of rice replication protein A (OsRPA70b), and the 32 kDa subunit 1 of rice replication protein A (OsRPA32-1). Irradiation of UV-B induces OsEXO1 expression while hydrogen peroxide treatment represses it. These results suggest that OsEXO1 plays an important role in both cell proliferation and UV-damaged nuclear DNA repair pathway under dark conditions.
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Affiliation(s)
- Tomoyuki Furukawa
- Division of Plant Biotechnology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
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6
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Matsuno M, Kose H, Okabe M, Hiromi Y. TFIIH controls developmentally-regulated cell cycle progression as a holocomplex. Genes Cells 2008; 12:1289-300. [PMID: 17986012 DOI: 10.1111/j.1365-2443.2007.01133.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Basal transcription factor, TFIIH, is a multifunctional complex that carries out not only transcription but also DNA repair and cell cycle control. TFIIH is composed of two sub-complexes: core TFIIH and Cdk-activating kinase (CAK). In vitro studies suggest that CAK is sufficient for cell cycle regulation, whereas core TFIIH is required for DNA repair. However, the TFIIH complexes that perform these functions in vivo have yet to be identified. Here, we perform an in vivo dissection of TFIIH activity by characterizing mutations in a core subunit p52 in Drosophila. p52 mutants are hypersensitive to UV, suggesting a defect in DNA repair. Nonetheless, mutant cells are able to divide and express a variety of differentiation markers. Although p52 is not essential for cell cycle progression itself, p52 mutant cells in the eye imaginal disc are unable to synchronize their cell cycles and remain arrested at G1. Similar cell cycle phenotypes are observed in mutations in another core subunit XPB and a CAK-component CDK7, suggesting that defects in core TFIIH affect the G1/S transition through modification of CAK activity. We propose that during development the function of TFIIH as a cell cycle regulator is carried out by holo-TFIIH.
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Affiliation(s)
- Motomi Matsuno
- Department of Developmental Genetics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
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7
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Laurencon A, Orme CM, Peters HK, Boulton CL, Vladar EK, Langley SA, Bakis EP, Harris DT, Harris NJ, Wayson SM, Hawley RS, Burtis KC. A large-scale screen for mutagen-sensitive loci in Drosophila. Genetics 2005; 167:217-31. [PMID: 15166149 PMCID: PMC1470880 DOI: 10.1534/genetics.167.1.217] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In a screen for new DNA repair mutants, we tested 6275 Drosophila strains bearing homozygous mutagenized autosomes (obtained from C. Zuker) for hypersensitivity to methyl methanesulfonate (MMS) and nitrogen mustard (HN2). Testing of 2585 second-chromosome lines resulted in the recovery of 18 mutants, 8 of which were alleles of known genes. The remaining 10 second-chromosome mutants were solely sensitive to MMS and define 8 new mutagen-sensitive genes (mus212-mus219). Testing of 3690 third chromosomes led to the identification of 60 third-chromosome mutants, 44 of which were alleles of known genes. The remaining 16 mutants define 14 new mutagen-sensitive genes (mus314-mus327). We have initiated efforts to identify these genes at the molecular level and report here the first two identified. The HN2-sensitive mus322 mutant defines the Drosophila ortholog of the yeast snm1 gene, and the MMS- and HN2-sensitive mus301 mutant defines the Drosophila ortholog of the human HEL308 gene. We have also identified a second-chromosome mutant, mus215(ZIII-2059), that uniformly reduces the frequency of meiotic recombination to <3% of that observed in wild type and thus defines a function required for both DNA repair and meiotic recombination. At least one allele of each new gene identified in this study is available at the Bloomington Stock Center.
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Affiliation(s)
- Anne Laurencon
- Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA
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8
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Ishikawa G, Kanai Y, Takata KI, Takeuchi R, Shimanouchi K, Ruike T, Furukawa T, Kimura S, Sakaguchi K. DmGEN, a novel RAD2 family endo-exonuclease from Drosophila melanogaster. Nucleic Acids Res 2004; 32:6251-9. [PMID: 15576351 PMCID: PMC535671 DOI: 10.1093/nar/gkh962] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A novel endo-exonuclease, DmGEN (Drosophila Melanogaster XPG-like endonuclease), was identified in D.melanogaster. DmGEN is composed of five exons and four introns, and the open reading frame encodes a predicted product of 726 amino acid residues with a molecular weight of 82.5 kDa and a pI of 5.36. The gene locus on Drosophila polytene chromosomes was detected at 64C9 on the left arm of chromosome 3 as a single site. The encoded protein showed a relatively high degree of sequence homology with the RAD2 nucleases, especially XPG. Although the XPG-N- and XPG-I-domains are highly conserved in sequence, locations of the domains are similar to those of FEN-1 and EXO-1, and the molecular weight of the protein is close to that of EXO-1. In vitro, DmGEN showed endonuclease and 3'-5' exonuclease activities with both single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), but the endonuclease action with dsDNA was quite specific: 5'-3' exonuclease activity was found to occur with nicked DNA, while dsDNA was endonucleolytically cut at 3-4 bp from the 5' end. Homologs are widely found in mammals and higher plants. The data suggest that DmGEN belongs to a new class of RAD2 nuclease.
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Affiliation(s)
- Gen Ishikawa
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-Shi, Chiba-ken 278 8510, Japan
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9
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Hernando J, Alvarez L, Ferreiro JA, Sancho I, Comendador MA, Sierra LM. Female germ cell mutagenicity of model chemicals in Drosophila melanogaster: mechanistic information and analysis of repair systems. Mutat Res 2004; 545:59-72. [PMID: 14698417 DOI: 10.1016/j.mrfmmm.2003.09.013] [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] [Indexed: 11/26/2022]
Abstract
In spite of differences between female and male germ cells, and although both of them contribute to the gene pool of future generations, most germ cell mutagenicity studies in higher eukaryotes have been carried out on males. To study the response of female germ cells to mutagen/carcinogen exposure, the mutagenicity of two model chemicals like diethyl sulfate (DES) and hexamethylphosphoramide (HMPA), and the monofunctional methylating chemotherapeutic drug streptozotocin (STZ), has been analysed on repair efficient females of Drosophila melanogaster. Results previously obtained with N-ethyl-N-nitrosourea (ENU), another model chemical, have also been included in the analysis. The activity of bypass tolerance mechanism (BTM; represented by the mus308 locus) and nucleotide excision repair (NER) on the removal of oxygen and nitrogen ethylations was studied by determining DES mutagenicity in NER deficient females, comparing it with existing results for ENU, and by analysing both chemicals on BTM deficient females. Results indicate that (1) all chemicals are mutagenic on repair efficient females; (2) a measure of mutagenic activity ranked from the lowest DES to STZ, HMPA, and ENU as the highest. This order correlates with the repair of the respectively induced DNA damages, and with the mutagenic and carcinogenic potency of these compounds, considering the toxicity of cross-linking agents; (3) NER efficiently repairs nitrogen ethylation damage and seems to contribute to the processing of oxygen damage in female germ cells; and (4) BTM is involved on the processing of oxygen ethylation damage, whereas the results on nitrogen ethylation are not clear. Finally, these results indicate that differences between male and female germ cells affect the response to chemical exposure, and therefore demonstrate the necessity of analysing also female cells in germinal mutagenicity studies. In addition, these studies can provide important mechanistic information about germ cell chemical mutagenesis, and even when the analysis of oogonia is not possible, since all female germ cells are pre-meiotic, studies of oocytes could be a model for pre-meiotic cells.
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Affiliation(s)
- Julia Hernando
- Area de Genética, Dpto. Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias, University of Oviedo, C/ Julián Clavería s/n, 33006 Oviedo, Spain
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10
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Vogel EW, Nivard MJM. Model systems for studying germ cell mutagens: from flies to mammals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 518:99-114. [PMID: 12817680 DOI: 10.1007/978-1-4419-9190-4_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Affiliation(s)
- Ekkehart W Vogel
- Leiden University Medical Centre, Department of Radiation Genetics and Chemical Mutagenesis, MGC Sylvius Laboratories, Wassenaarseweg 72, 2300 RA Leiden, The Netherlands.
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11
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Kimura S, Furukawa T, Kasai N, Mori Y, Kitamoto HK, Sugawara F, Hashimoto J, Sakaguchi K. Functional characterization of two flap endonuclease-1 homologues in rice. Gene 2003; 314:63-71. [PMID: 14527718 DOI: 10.1016/s0378-1119(03)00694-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Flap endonuclease-1 (FEN-1) is an important enzyme involved in DNA replication and repair. Previously, we isolated and characterized a complementary DNA (cDNA) from rice (Oryza sativa) encoding a protein which shows homology with the eukaryotic flap endonuclease-1 (FEN-1). In this report, we found that rice (O. sativa L. cv. Nipponbare) possessed two FEN-1 homologues designated as OsFEN-1a and OsFEN-1b. The OsFEN-1a and OsFEN-1b genes were mapped to chromosome 5 and 3, respectively. Both genes contained 17 exons and 16 introns. Alignment of OsFEN-1a protein with OsFEN-1b protein showed a high degree of sequence similarity, particularly around the N and I domains. Northern hybridization and in situ hybridization analysis demonstrated preferential expression of OsFEN-1a and OsFEN-1b in proliferating tissues such as the shoot apical meristem or young leaves. The levels of OsFEN-1a and OsFEN-1b expression were significantly reduced when cell proliferation was temporarily halted by the removal of sucrose from the growth medium. When the growth-halted cells began to regrow following the addition of sucrose to the medium, both OsFEN-1a and OsFEN-1b were again expressed at high level. These results suggested that OsFEN-1a and OsFEN-1b are required for cell proliferation. Functional complementation assay suggested that OsFEN-1a cDNA had the ability to complement Saccharomyces cerevisiae rad27 null mutant. On the other hand, OsFEN-1b cDNA could not complement the rad27 mutant. The roles of OsFEN-1a and OsFEN-1b in plant DNA replication and repair are discussed.
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Affiliation(s)
- Seisuke Kimura
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Chiba, 278-8510, Noda, Japan
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12
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Alvarez L, Comendador MA, Sierra LM. Effect of nucleotide excision repair on ENU-induced mutation in female germ cells of Drosophila melanogaster. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2003; 41:270-279. [PMID: 12717782 DOI: 10.1002/em.10149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The role of nucleotide excision repair (NER) in the repair of alkylation damage in the germ cells of higher eukaryotes has been studied mainly by treating postmeiotic male germ cells. Little is known about repair in actively repairing female germ cells. In this study, we treated NER-deficient (ner(-)) mus201(D1) Drosophila females with N-ethyl-N-nitrosourea (ENU) and determined both the mutant frequencies in the multiple locus recessive lethal (RL) test and in the single locus vermilion gene and determined the ENU mutation spectrum in the vermilion gene. The results show that ENU is mutagenic in all cell stages and that the induced frequencies increase with cell maturation, from oogonia to mature oocytes. In addition, the induced spectrum consists mainly of A:T-->T:A transversions (43.8%), A:T-->G:C transitions (21.9%), and A:T-->C:G transversions (15.6%). G:C-->A:T (3.1%) transitions, other transversions (9.4%), frameshifts (3.1%), and deletions (3.1%) were also found. Comparison of these results with those previously obtained for repair-proficient (ner(+)) female germ cells reveal: 1) Differences in the RL and vermilion mutation frequencies for ner(+) and ner(-) germ cells, indicating that NER is involved in the repair of ENU-induced damage to these cells. 2) At least 15.6% of mutations in ner(-) cells may be the consequence of N-ethylation damage and mutations of this type were not detected in ner(+) cells. 3) Although differences were found in transition frequencies between ENU-treated ner(+) and ner(-) germ cells (52.2% vs. 25%), suggesting that a functional NER is involved in processing O-ethylated damage, the role of NER in repairing O-ethylated adducts is uncertain.
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Affiliation(s)
- L Alvarez
- Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias, Area de Genética, Universidad de Oviedo, Oviedo, Spain
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13
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Bilbao C, Ferreiro JA, Comendador MA, Sierra LM. Influence of mus201 and mus308 mutations of Drosophila melanogaster on the genotoxicity of model chemicals in somatic cells in vivo measured with the comet assay. Mutat Res 2002; 503:11-9. [PMID: 12052499 DOI: 10.1016/s0027-5107(02)00070-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To check the possibilities of the recently developed comet assay, to be used in mechanistic studies in Drosophila melanogaster, neuroblast cells of third instar larvae are used to analyse in vivo, the effect of two repair deficient mutations: mus201, deficient on nucleotide excision repair, and mus308, deficient in a mechanism of damage bypass, on the genotoxicity of methyl methanesulphonate (MMS), ethyl methanesulphonate (EMS) and N-ethyl-N-nitrosourea (ENU). The obtained results reveal: (1) MMS-induced breaks are most probably consequence of N-alkylation damage mediated abasic (AP) site breakage; (2) MMS and at least part of the EMS induced damage leading to DNA strand breaks are efficiently repaired by the nucleotide excision repair mechanism; (3) ENU and part of EMS induced damage need a functional Mus308 protein to be processed, otherwise they can lead to DNA strand breaks. In addition, the results of this work confirm the validity of neuroblast cells to conduct the comet assay, and the usefulness of this assay in in vivo mechanistic studies related to DNA repair in D. melanogaster.
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Affiliation(s)
- Cristina Bilbao
- Departamento de Biología, Funcional e Instituto Universitario de Oncología Area de Genética, University of Oviedo, C/Julián Clavería s/n, 33006 Oviedo, Spain
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14
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Vogel EW, Nivard MJ. Phenotypes of Drosophila homologs of human XPF and XPG to chemically-induced DNA modifications. Mutat Res 2001; 476:149-65. [PMID: 11336992 DOI: 10.1016/s0027-5107(01)00121-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
DmXPF (mei9) and DmXPG (mus201) mutants are Drosophila homologs of the mammalian XPF and XPG genes, respectively. For Drosophila germ cells, causal correlations exist between the magnitude of a potentiating effect of a deficiency in these functions, measured as the M(NER-)/M(NER+) mutability ratio, and the type of DNA modification. M(NER-)/M(NER+) mutability ratios may vary with time interval between DNA adduct formation and repair, mutagen dose and depend also on the genetic endpoint measured. For forward mutations, there is no indication of any differential response of DmXPF compared to DmXPG. Subtle features appeared from a class-by-class comparison: (i) Methylating agents always produce higher M(NER-)/M(NER+) ratios than their ethylating analogs; (ii) M(NER-)/M(NER+) mutability ratios are significantly enhanced for cross-linking N-mustards, aziridine and di-epoxide compounds, but not for cross-linking nitrosoureas. The low hypermutability effects with bifunctional nitrogen mustards, aziridine and epoxide compounds are attributed to unrepaired mono-alkyl adducts; (iii) The efficient repair of mono-alkyl-adducts at ring nitrogens in wild-type germ cells is evident from the absence of a dose-response relationship for ethylene oxide, propylene imine and methyl methanesulfonate (MMS). These chemicals become powerful germline mutagens when the NER system is disrupted. Systematic studies of the type performed on germ cells are not available for somatic cells of Drosophila. The sparse data available show large differences in the response of germ cells and somatic cells. The bifunctional agent mechlorethamine (MEC) but not the monofunctional MMS or 2-chloroethylamine cause in NER(-) XXfemale symbol the highest potentiating effect on mitotic recombination. The causes of the discrepancy between the extraordinarily high activity of MEC in mus201 somatic cells and its low potentiating effect in germ cells is unknown at present.
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Affiliation(s)
- E W Vogel
- Department of Radiation Genetics & Chemical Mutagenesis, MGC Sylvius Laboratories, Leiden University Medical Centre, Wassenaarseweg 72, 2300 RA Leiden, The Netherlands.
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15
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Eeken JC, Romeijn RJ, de Jong AW, Pastink A, Lohman PH. Isolation and genetic characterisation of the Drosophila homologue of (SCE)REV3, encoding the catalytic subunit of DNA polymerase zeta. Mutat Res 2001; 485:237-53. [PMID: 11267835 DOI: 10.1016/s0921-8777(01)00062-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In Drosophila, about 30 mutants are known that show hypersensitivity to the methylating agent methyl methane sulfonate (MMS). Addition of this agent to the medium results in an increased larval mortality of the mutants. Using a P-insertion mutagenesis screen, three MMS-sensitive mutants on chromosome II were isolated. One of these is allelic to the known EMS-induced mus205 (mutagen sensitive) mutant. In the newly isolated mutant, a P-element is detected in region 43E by in situ hybridisation. The localisation of mus205 to this region was confirmed by deficiency mapping. The gene was cloned and shows strong homology to the Saccharomyces cerevisiae REV3 gene. The REV3 gene encodes the catalytic subunit of DNA polymerase zeta, involved in translesion synthesis. The P-element is inserted in the first exon of the mus205 gene resulting in an aberrant mRNA, encoding a putative truncated protein containing only the first 13 of the 2130 aa native Drosophila protein. The mus205 mutant is hypersensitive to alkylating agents and UV, but not to ionising radiation. In contrast to reported data, in germ cells, the mutant has no effect on mutability by X-rays, NQO and alkylating agents. In somatic cells, the mutant shows no effect on MMS-induced mutations and recombinations. This phenotype of the Drosophila mus205 mutant is strikingly different from the phenotype of the yeast rev3 mutant, which is hypomutable after UV, X-rays, NQO and alkylating agents.
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Affiliation(s)
- J C Eeken
- Department of Radiation Genetics and Chemical Mutagenesis, MGC, Leiden University Medical Center, P.O. Box 9503, 2300 RF, Leiden, The Netherlands.
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