1
|
Koike M, Yamashita H, Yutoku Y, Koike A. Molecular cloning, subcellular localization, and rapid recruitment to DNA damage sites of chicken Ku70. Sci Rep 2024; 14:1188. [PMID: 38216643 PMCID: PMC10786929 DOI: 10.1038/s41598-024-51501-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/05/2024] [Indexed: 01/14/2024] Open
Abstract
Ku70 is a multifunctional protein with pivotal roles in DNA repair via non-homologous end-joining, V(D)J recombination, telomere maintenance, and neuronal apoptosis control. Nonetheless, its regulatory mechanisms remain elusive. Chicken Ku70 (GdKu70) cDNA has been previously cloned, and DT40 cells expressing it have significantly contributed to critical biological discoveries. GdKu70 features an additional 18 amino acids at its N-terminus compared to mammalian Ku70, the biological significance of which remains uncertain. Here, we show that the 5' flanking sequence of GdKu70 cDNA is not nearly encoded in the chicken genome. Notably, these 18 amino acids result from fusion events involving the NFE2L1 gene on chromosome 27 and the Ku70 gene on chromosome 1. Through experiments using newly cloned chicken Ku70 cDNA and specific antibodies, we demonstrated that Ku70 localizes within the cell nucleus as a heterodimer with Ku80 and promptly accumulates at DNA damage sites following injury. This suggests that the functions and spatiotemporal regulatory mechanisms of Ku70 in chickens closely resemble those in mammals. The insights and resources acquired will contribute to elucidate the various mechanisms by which Ku functions. Meanwhile, caution is advised when interpreting the previous numerous key studies that relied on GdKu70 cDNA and its expressing cells.
Collapse
Affiliation(s)
- Manabu Koike
- Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
- Life Science Course, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, Saitama, 338-8570, Japan.
| | - Hideji Yamashita
- Department of Food and Life Sciences, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto, 862-8652, Japan
| | - Yasutomo Yutoku
- Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Aki Koike
- Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| |
Collapse
|
2
|
Bello A, Hirth G, Voigt S, Tepper S, Jungnickel B. Mechanism and regulation of secondary immunoglobulin diversification. Cell Cycle 2023; 22:2070-2087. [PMID: 37909747 PMCID: PMC10761156 DOI: 10.1080/15384101.2023.2275397] [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: 05/04/2023] [Accepted: 10/20/2023] [Indexed: 11/03/2023] Open
Abstract
Secondary immunoglobulin diversification by somatic hypermutation and class switch recombination in B cells is instrumental for an adequate adaptive humoral immune response. These genetic events may, however, also introduce aberrations into other cellular genes and thereby cause B cell malignancies. While the basic mechanism of somatic hypermutation and class switch recombination is now well understood, their regulation and in particular the mechanism of their specific targeting to immunoglobulin genes is still rather mysterious. In this review, we summarize the current knowledge on the mechanism and regulation of secondary immunoglobulin diversification and discuss known mechanisms of physiological targeting to immunoglobulin genes and mistargeting to other cellular genes. We summarize open questions in the field and provide an outlook on future research.
Collapse
Affiliation(s)
- Amanda Bello
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Gianna Hirth
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Stefanie Voigt
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Sandra Tepper
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Berit Jungnickel
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| |
Collapse
|
3
|
Ďurovcová I, Kyzek S, Fabová J, Makuková J, Gálová E, Ševčovičová A. Genotoxic potential of bisphenol A: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 306:119346. [PMID: 35489531 DOI: 10.1016/j.envpol.2022.119346] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/05/2022] [Accepted: 04/20/2022] [Indexed: 05/25/2023]
Abstract
Bisphenol A (BPA), as a major component of some plastic products, is abundant environmental pollutant. Due to its ability to bind to several types of estrogen receptors, it can trigger multiple cellular responses, which can contribute to various manifestations at the organism level. The most studied effect of BPA is endocrine disruption, but recently its prooxidative potential has been confirmed. BPA ability to induce oxidative stress through increased ROS production, altered activity of antioxidant enzymes, or accumulation of oxidation products of biomacromolecules is observed in a wide range of organisms - estrogen receptor-positive and -negative. Subsequently, increased intracellular oxidation can lead to DNA damage induction, represented by oxidative damage, single- and double-strand DNA breaks. Importantly, BPA shows several mechanisms of action and can trigger adverse effects on all organisms inhabiting a wide variety of ecosystem types. Therefore, the main aim of this review is to summarize the genotoxic effects of BPA on organisms across all taxa.
Collapse
Affiliation(s)
- Ivana Ďurovcová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Stanislav Kyzek
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Jana Fabová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Jana Makuková
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Eliška Gálová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Andrea Ševčovičová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| |
Collapse
|
4
|
Tsuda M, Shimizu N, Tomikawa H, Morozumi R, Ide H. Repair pathways for radiation DNA damage under normoxic and hypoxic conditions: Assessment with a panel of repair-deficient human TK6 cells. JOURNAL OF RADIATION RESEARCH 2021:rrab084. [PMID: 34562004 DOI: 10.1093/jrr/rrab084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/16/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
Various types of DNA lesions are produced when cells are exposed to ionizing radiation (IR). The type and yield of IR-induced DNA damage is influenced by the oxygen concentration. Thus, different DNA repair mechanisms may be involved in the response of normoxic and hypoxic cells to irradiation with IR. However, differences between the repair mechanisms of IR-induced DNA damage under normoxic versus hypoxic conditions have not been clarified. Elucidating the relative contribution of individual repair factors to cell survival would give insight into the repair mechanisms operating in irradiated normoxic and hypoxic cells. In the present study, we used a panel of repair-deficient human TK6 cell lines that covered seven repair pathways. Cells were irradiated with X-rays under normoxic and hypoxic conditions, and the sensitivities of each mutant relative to the wild-type (i.e. relative sensitivity) were determined for normoxic and hypoxic conditions. The sensitivity of cells varied depending on the type of repair defects. However, for each repair mutant, the relative sensitivity under normoxic conditions was comparable to that under hypoxic conditions. This result indicates that the relative contribution of individual repair pathways to cell survival is comparable in normoxic and hypoxic cells, although the spectrum of IR-induced DNA damage in hypoxic cells differs from that of normoxic cells.
Collapse
Affiliation(s)
- Masataka Tsuda
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Naoto Shimizu
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Hinako Tomikawa
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Ryosuke Morozumi
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Hiroshi Ide
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| |
Collapse
|
5
|
Abe T, Suzuki Y, Ikeya T, Hirota K. Targeting chromosome trisomy for chromosome editing. Sci Rep 2021; 11:18054. [PMID: 34508128 PMCID: PMC8433146 DOI: 10.1038/s41598-021-97580-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/25/2021] [Indexed: 11/09/2022] Open
Abstract
A trisomy is a type of aneuploidy characterised by an additional chromosome. The additional chromosome theoretically accepts any kind of changes since it is not necessary for cellular proliferation. This advantage led us to apply two chromosome manipulation methods to autosomal trisomy in chicken DT40 cells. We first corrected chromosome 2 trisomy to disomy by employing counter-selection markers. Upon construction of cells carrying markers targeted in one of the trisomic chromosome 2s, cells that have lost markers integrated in chromosome 2 were subsequently selected. The loss of one of the chromosome 2s had little impacts on the proliferative capacity, indicating unsubstantial role of the additional chromosome 2 in DT40 cells. We next tested large-scale truncations of chromosome 2 to make a mini-chromosome for the assessment of chromosome stability by introducing telomere repeat sequences to delete most of p-arm or q-arm of chromosome 2. The obtained cell lines had 0.7 Mb mini-chromosome, and approximately 0.2% of mini-chromosome was lost per cell division in wild-type background while the rate of chromosome loss was significantly increased by the depletion of DDX11, a cohesin regulatory protein. Collectively, our findings propose that trisomic chromosomes are good targets to make unique artificial chromosomes.
Collapse
Affiliation(s)
- Takuya Abe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan.
| | - Yuya Suzuki
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Teppei Ikeya
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| |
Collapse
|
6
|
Uncovering molecular mechanisms of regulated cell death in the naked mole rat. Aging (Albany NY) 2021; 13:3239-3253. [PMID: 33510044 PMCID: PMC7906159 DOI: 10.18632/aging.202577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 12/14/2020] [Indexed: 11/25/2022]
Abstract
The naked mole rat (NMR), Heterocephalus glaber, is the longest-living rodent species, and is extraordinarily resistant to cancer and aging-related diseases. The molecular basis for these unique phenotypic traits of the NMR is under extensive research. However, the role of regulated cell death (RCD) in the longevity and the protection from cancer in the NMR is still largely unknown. RCD is a mechanism restricting the proliferation of damaged or premalignant cells, which counteracts aging and oncotransformation. In this study, DNA damage-induced cell death in NMR fibroblasts was investigated in comparison to RCD in fibroblasts from Mus musculus. The effects of methyl methanesulfonate, 5-fluorouracil, and etoposide in both cell types were examined using contemporary cell death analyses. Skin fibroblasts from Heterocephalus glaber were found to be more resistant to the action of DNA damaging agents compared to fibroblasts from Mus musculus. Strikingly, our results revealed that NMR cells also exhibit a limited apoptotic response and seem to undergo regulated necrosis. Taken together, this study provides new insights into the mechanisms of cell death in NMR expanding our understanding of longevity, and it paves the way towards the development of innovative therapeutic approaches.
Collapse
|
7
|
Lerksuthirat T, Wikiniyadhanee R, Chitphuk S, Stitchantrakul W, Sampattavanich S, Jirawatnotai S, Jumpathong J, Dejsuphong D. DNA Repair Biosensor-Identified DNA Damage Activities of Endophyte Extracts from Garcinia cowa. Biomolecules 2020; 10:E1680. [PMID: 33339185 PMCID: PMC7765599 DOI: 10.3390/biom10121680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/04/2020] [Accepted: 12/10/2020] [Indexed: 12/03/2022] Open
Abstract
Recent developments in chemotherapy focus on target-specific mechanisms, which occur only in cancer cells and minimize the effects on normal cells. DNA damage and repair pathways are a promising target in the treatment of cancer. In order to identify novel compounds targeting DNA repair pathways, two key proteins, 53BP1 and RAD54L, were tagged with fluorescent proteins as indicators for two major double strand break (DSB) repair pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). The engineered biosensor cells exhibited the same DNA repair properties as the wild type. The biosensor cells were further used to investigate the DNA repair activities of natural biological compounds. An extract from Phyllosticta sp., the endophyte isolated from the medicinal plant Garcinia cowa Roxb. ex Choisy, was tested. The results showed that the crude extract induced DSB, as demonstrated by the increase in the DNA DSB marker γH2AX. The damaged DNA appeared to be repaired through NHEJ, as the 53BP1 focus formation in the treated fraction was higher than in the control group. In conclusion, DNA repair-based biosensors are useful for the preliminary screening of crude extracts and biological compounds for the identification of potential targeted therapeutic drugs.
Collapse
Affiliation(s)
- Tassanee Lerksuthirat
- Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (T.L.); (S.C.); (W.S.)
| | - Rakkreat Wikiniyadhanee
- Section for Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand;
| | - Sermsiri Chitphuk
- Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (T.L.); (S.C.); (W.S.)
| | - Wasana Stitchantrakul
- Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (T.L.); (S.C.); (W.S.)
| | - Somponnat Sampattavanich
- Siriraj Center of Research for Excellence (SiCORE) for Systems Pharmacology, Department of Pharmacology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (S.S.); (S.J.)
| | - Siwanon Jirawatnotai
- Siriraj Center of Research for Excellence (SiCORE) for Systems Pharmacology, Department of Pharmacology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (S.S.); (S.J.)
| | - Juangjun Jumpathong
- Center of Excellent in Research for Agricultural Biotechnology and Department of Agricultural Science, Faculty of Agriculture, Natural Resources and Environment, Naresuan University, Phitsanulok 65000, Thailand
| | - Donniphat Dejsuphong
- Section for Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand;
| |
Collapse
|
8
|
Crickard JB, Moevus CJ, Kwon Y, Sung P, Greene EC. Rad54 Drives ATP Hydrolysis-Dependent DNA Sequence Alignment during Homologous Recombination. Cell 2020; 181:1380-1394.e18. [PMID: 32502392 DOI: 10.1016/j.cell.2020.04.056] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/07/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022]
Abstract
Homologous recombination (HR) helps maintain genome integrity, and HR defects give rise to disease, especially cancer. During HR, damaged DNA must be aligned with an undamaged template through a process referred to as the homology search. Despite decades of study, key aspects of this search remain undefined. Here, we use single-molecule imaging to demonstrate that Rad54, a conserved Snf2-like protein found in all eukaryotes, switches the search from the diffusion-based pathways characteristic of the basal HR machinery to an active process in which DNA sequences are aligned via an ATP-dependent molecular motor-driven mechanism. We further demonstrate that Rad54 disrupts the donor template strands, enabling the search to take place within a migrating DNA bubble-like structure that is bound by replication protein A (RPA). Our results reveal that Rad54, working together with RPA, fundamentally alters how DNA sequences are aligned during HR.
Collapse
Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Corentin J Moevus
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
9
|
Póti Á, Gyergyák H, Németh E, Rusz O, Tóth S, Kovácsházi C, Chen D, Szikriszt B, Spisák S, Takeda S, Szakács G, Szallasi Z, Richardson AL, Szüts D. Correlation of homologous recombination deficiency induced mutational signatures with sensitivity to PARP inhibitors and cytotoxic agents. Genome Biol 2019; 20:240. [PMID: 31727117 PMCID: PMC6857305 DOI: 10.1186/s13059-019-1867-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/28/2019] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Homologous recombination (HR) repair deficiency arising from defects in BRCA1 or BRCA2 is associated with characteristic patterns of somatic mutations. In this genetic study, we ask whether inactivating mutations in further genes of the HR pathway or the DNA damage checkpoint also give rise to somatic mutation patterns that can be used for treatment prediction. RESULTS Using whole genome sequencing of an isogenic knockout cell line panel, we find a universal HR deficiency-specific base substitution signature that is similar to COSMIC signature 3. In contrast, we detect different deletion phenotypes corresponding to specific HR mutants. The inactivation of BRCA2 or PALB2 leads to larger deletions, typically with microhomology, when compared to the disruption of BRCA1, RAD51 paralogs, or RAD54. Comparison with the deletion spectrum of Cas9 cut sites suggests that most spontaneously arising genomic deletions are not the consequence of double-strand breaks. Surprisingly, the inactivation of checkpoint kinases ATM and CHK2 has no mutagenic consequences. Analysis of tumor exomes with biallelic inactivating mutations in the investigated genes confirms the validity of the cell line models. We present a comprehensive analysis of sensitivity of the investigated mutants to 13 therapeutic agents for the purpose of correlating genomic mutagenic phenotypes with drug sensitivity. CONCLUSION Our results suggest that no single genomic mutational class shows perfect correlation with sensitivity to common treatments, but the contribution of COSMIC signature 3 to base substitutions, or a combined measure of different features, may be reasonably good at predicting platinum and PARP inhibitor sensitivity.
Collapse
Affiliation(s)
- Ádám Póti
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Hella Gyergyák
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Eszter Németh
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Orsolya Rusz
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | - Szilárd Tóth
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Csenger Kovácsházi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Dan Chen
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Bernadett Szikriszt
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
| | - Sándor Spisák
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Shunichi Takeda
- Department of Radiation Genetics, Kyoto University Medical School, Kyoto, 606-8501, Japan
| | - Gergely Szakács
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary
- Institute of Cancer Research, Medical University Vienna, Vienna, Austria
| | - Zoltan Szallasi
- Computational Health Informatics Program (CHIP), Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Danish Cancer Society Research Center, Copenhagen, Denmark
- SE-NAP, Brain Metastasis Research Group, 2nd Department of Pathology, Semmelweis University, Budapest, Hungary
| | | | - Dávid Szüts
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudosok krt 2, Budapest, H-1117, Hungary.
| |
Collapse
|
10
|
Abe T, Branzei D, Hirota K. DNA Damage Tolerance Mechanisms Revealed from the Analysis of Immunoglobulin V Gene Diversification in Avian DT40 Cells. Genes (Basel) 2018; 9:genes9120614. [PMID: 30544644 PMCID: PMC6316486 DOI: 10.3390/genes9120614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/26/2018] [Accepted: 11/30/2018] [Indexed: 01/19/2023] Open
Abstract
DNA replication is an essential biochemical reaction in dividing cells that frequently stalls at damaged sites. Homologous/homeologous recombination (HR)-mediated template switch and translesion DNA synthesis (TLS)-mediated bypass processes release arrested DNA replication forks. These mechanisms are pivotal for replication fork maintenance and play critical roles in DNA damage tolerance (DDT) and gap-filling. The avian DT40 B lymphocyte cell line provides an opportunity to examine HR-mediated template switch and TLS triggered by abasic sites by sequencing the constitutively diversifying immunoglobulin light-chain variable gene (IgV). During IgV diversification, activation-induced deaminase (AID) converts dC to dU, which in turn is excised by uracil DNA glycosylase and yields abasic sites within a defined window of around 500 base pairs. These abasic sites can induce gene conversion with a set of homeologous upstream pseudogenes via the HR-mediated template switch, resulting in templated mutagenesis, or can be bypassed directly by TLS, resulting in non-templated somatic hypermutation at dC/dG base pairs. In this review, we discuss recent works unveiling IgV diversification mechanisms in avian DT40 cells, which shed light on DDT mode usage in vertebrate cells and tolerance of abasic sites.
Collapse
Affiliation(s)
- Takuya Abe
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
| | - Dana Branzei
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100 Pavia, Italy.
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
| |
Collapse
|
11
|
Lanning DK, Knight KL. Diversification of the Primary Antibody Repertoire by AID-Mediated Gene Conversion. Results Probl Cell Differ 2016; 57:279-93. [PMID: 26537386 DOI: 10.1007/978-3-319-20819-0_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gene conversion, mediated by activation-induced cytidine deaminase (AID), has been found to contribute to generation of the primary antibody repertoire in several vertebrate species. Generation of the primary antibody repertoire by gene conversion of immunoglobulin (Ig) genes occurs primarily in gut-associated lymphoid tissues (GALT) and is best described in chicken and rabbit. Here, we discuss current knowledge of the mechanism of gene conversion as well as the contribution of the microbiota in promoting gene conversion of Ig genes. Finally, we propose that the antibody diversification strategy used in GALT species, such as chicken and rabbit, is conserved in a subset of human and mouse B cells.
Collapse
Affiliation(s)
- Dennis K Lanning
- Department of Microbiology and Immunology, Loyola University Chicago, 2160 S. First Avenue, Maywood, IL, 60153, USA
| | - Katherine L Knight
- Department of Microbiology and Immunology, Loyola University Chicago, 2160 S. First Avenue, Maywood, IL, 60153, USA.
| |
Collapse
|
12
|
Gao X, Zhang G, Shan S, Shang Y, Chi L, Li H, Cao Y, Zhu X, Zhang M, Yang J. Depletion of Paraspeckle Protein 1 Enhances Methyl Methanesulfonate-Induced Apoptosis through Mitotic Catastrophe. PLoS One 2016; 11:e0146952. [PMID: 26785254 PMCID: PMC4718682 DOI: 10.1371/journal.pone.0146952] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/22/2015] [Indexed: 11/19/2022] Open
Abstract
Previously, we have shown that paraspeckle protein 1 (PSPC1), a protein component of paraspeckles that was involved in cisplatin-induced DNA damage response (DDR), probably functions at the G1/S checkpoint. In the current study, we further examined the role of PSPC1 in another DNA-damaging agent, methyl methanesulfonate (MMS)-induced DDR, in particular, focusing on MMS-induced apoptosis in HeLa cells. First, it was found that MMS treatment induced the expression of PSPC1. While MMS treatment alone can induce apoptosis, depletion of PSPC1 expression using siRNA significantly increased the level of apoptosis following MMS exposure. In contrast, overexpressing PSPC1 decreased the number of apoptotic cells. Interestingly, morphological observation revealed that many of the MMS-treated PSPC1-knockdown cells contained two or more nuclei, indicating the occurrence of mitotic catastrophe. Cell cycle analysis further showed that depletion of PSPC1 caused more cells entering the G2/M phase, a prerequisite of mitosis catastrophe. On the other hand, over-expressing PSPC1 led to more cells accumulating in the G1/S phase. Taken together, these observations suggest an important role for PSPC1 in MMS-induced DDR, and in particular, depletion of PSPC1 can enhance MMS-induced apoptosis through mitotic catastrophe.
Collapse
Affiliation(s)
- Xiangjing Gao
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, 310051, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
| | - Guanglin Zhang
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
| | - Shigang Shan
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
| | - Yunlong Shang
- Zhejiang CONBA Pharmaceutical Co. Ltd., Hangzhou, Zhejiang, 310058, China
| | - Linfeng Chi
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Hongjuan Li
- Department of Toxicology, Hangzhou Normal University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Yifei Cao
- Department of Toxicology, Hangzhou Normal University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Xinqiang Zhu
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
| | - Meibian Zhang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, 310051, China
- * E-mail: (MBZ); (JY)
| | - Jun Yang
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, 310003, China
- Department of Toxicology, Hangzhou Normal University School of Medicine, Hangzhou, Zhejiang, 310016, China
- * E-mail: (MBZ); (JY)
| |
Collapse
|
13
|
Nishihara K, Huang R, Zhao J, Shahane SA, Witt KL, Smith-Roe SL, Tice RR, Takeda S, Xia M. Identification of genotoxic compounds using isogenic DNA repair deficient DT40 cell lines on a quantitative high throughput screening platform. Mutagenesis 2015; 31:69-81. [PMID: 26243743 DOI: 10.1093/mutage/gev055] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
DNA repair pathways play a critical role in maintaining cellular homeostasis by repairing DNA damage induced by endogenous processes and xenobiotics, including environmental chemicals. Induction of DNA damage may lead to genomic instability, disruption of cellular homeostasis and potentially tumours. Isogenic chicken DT40 B-lymphocyte cell lines deficient in DNA repair pathways can be used to identify genotoxic compounds and aid in characterising the nature of the induced DNA damage. As part of the US Tox21 program, we previously optimised several different DT40 isogenic clones on a high-throughput screening platform and confirmed the utility of this approach for detecting genotoxicants by measuring differential cytotoxicity in wild-type and DNA repair-deficient clones following chemical exposure. In the study reported here, we screened the Tox21 10K compound library against two isogenic DNA repair-deficient DT40 cell lines (KU70 (-/-) /RAD54 (-/-) and REV3 (-/-) ) and the wild-type cell line using a cell viability assay that measures intracellular adenosine triphosphate levels. KU70 and RAD54 are genes associated with DNA double-strand break repair processes, and REV3 is associated with translesion DNA synthesis pathways. Active compounds identified in the primary screening included many well-known genotoxicants (e.g. adriamycin, melphalan) and several compounds previously untested for genotoxicity. A subset of compounds was further evaluated by assessing their ability to induce micronuclei and phosphorylated H2AX. Using this comprehensive approach, three compounds with previously undefined genotoxicity-2-oxiranemethanamine, AD-67 and tetraphenylolethane glycidyl ether-were identified as genotoxic. These results demonstrate the utility of this approach for identifying and prioritising compounds that may damage DNA.
Collapse
Affiliation(s)
- Kana Nishihara
- Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo, Kyoto 606-8501, Japan, National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, MSC: 3375 Bethesda, MD 20892, USA and
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, MSC: 3375 Bethesda, MD 20892, USA and
| | - Jinghua Zhao
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, MSC: 3375 Bethesda, MD 20892, USA and
| | - Sampada A Shahane
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, MSC: 3375 Bethesda, MD 20892, USA and
| | - Kristine L Witt
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Stephanie L Smith-Roe
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Raymond R Tice
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Shunichi Takeda
- Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo, Kyoto 606-8501, Japan
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, MSC: 3375 Bethesda, MD 20892, USA and
| |
Collapse
|
14
|
Dillon LW, Kumar P, Shibata Y, Wang YH, Willcox S, Griffith JD, Pommier Y, Takeda S, Dutta A. Production of Extrachromosomal MicroDNAs Is Linked to Mismatch Repair Pathways and Transcriptional Activity. Cell Rep 2015; 11:1749-59. [PMID: 26051933 DOI: 10.1016/j.celrep.2015.05.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/20/2015] [Accepted: 05/11/2015] [Indexed: 12/15/2022] Open
Abstract
MicroDNAs are <400-base extrachromosomal circles found in mammalian cells. Tens of thousands of microDNAs have been found in all tissue types, including sperm. MicroDNAs arise preferentially from areas with high gene density, GC content, and exon density from promoters with activating chromatin modifications and in sperm from the 5'-UTR of full-length LINE-1 elements, but are depleted from lamin-associated heterochromatin. Analysis of microDNAs from a set of human cancer cell lines revealed lineage-specific patterns of microDNA origins. A survey of microDNAs from chicken cells defective in various DNA repair proteins reveals that homologous recombination and non-homologous end joining repair pathways are not required for microDNA production. Deletion of the MSH3 DNA mismatch repair protein results in a significant decrease in microDNA abundance, specifically from non-CpG genomic regions. Thus, microDNAs arise as part of normal cellular physiology—either from DNA breaks associated with RNA metabolism or from replication slippage followed by mismatch repair.
Collapse
Affiliation(s)
- Laura W Dillon
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Pankaj Kumar
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yoshiyuki Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Yves Pommier
- Laboratory of Molecular Pharmacology and Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
| | - Shunichi Takeda
- CREST Research Project, Japan Science and Technology Corporation, Radiation Genetics, Faculty of Medicine, Kyoto University, Konoe Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
| |
Collapse
|
15
|
Tada K, Kobayashi M, Takiuchi Y, Iwai F, Sakamoto T, Nagata K, Shinohara M, Io K, Shirakawa K, Hishizawa M, Shindo K, Kadowaki N, Hirota K, Yamamoto J, Iwai S, Sasanuma H, Takeda S, Takaori-Kondo A. Abacavir, an anti-HIV-1 drug, targets TDP1-deficient adult T cell leukemia. SCIENCE ADVANCES 2015; 1:e1400203. [PMID: 26601161 PMCID: PMC4640626 DOI: 10.1126/sciadv.1400203] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/29/2015] [Indexed: 05/07/2023]
Abstract
Adult T cell leukemia (ATL) is an aggressive T cell malignancy caused by human T cell leukemia virus type 1 (HTLV-1) and has a poor prognosis. We analyzed the cytotoxic effects of various nucleoside analog reverse transcriptase inhibitors (NRTIs) for HIV-1 on ATL cells and found that abacavir potently and selectively kills ATL cells. Although NRTIs have minimal genotoxicities on host cells, the therapeutic concentration of abacavir induced numerous DNA double-strand breaks (DSBs) in the chromosomal DNA of ATL cells. DSBs persisted over time in ATL cells but not in other cell lines, suggesting impaired DNA repair. We found that the reduced expression of tyrosyl-DNA phosphodiesterase 1 (TDP1), a repair enzyme, is attributable to the cytotoxic effect of abacavir on ATL cells. We also showed that TDP1 removes abacavir from DNA ends in vitro. These results suggest a model in which ATL cells with reduced TDP1 expression are unable to excise abacavir incorporated into genomic DNA, leading to irreparable DSBs. On the basis of the above mechanism, we propose abacavir as a promising chemotherapeutic agent for ATL.
Collapse
Affiliation(s)
- Kohei Tada
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masayuki Kobayashi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
- Corresponding author: E-mail: (M.K.); (A.T.-K.)
| | - Yoko Takiuchi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Fumie Iwai
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takashi Sakamoto
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kayoko Nagata
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masanobu Shinohara
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Katsuhiro Io
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kotaro Shirakawa
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masakatsu Hishizawa
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Keisuke Shindo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Norimitsu Kadowaki
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Junpei Yamamoto
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Shigenori Iwai
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
- Corresponding author: E-mail: (M.K.); (A.T.-K.)
| |
Collapse
|
16
|
Eid MMA, Maeda K, Almofty SA, Singh SK, Shimoda M, Sakaguchi N. GANP regulates the choice of DNA repair pathway by DNA-PKcs interaction in AID-dependent IgV region diversification. THE JOURNAL OF IMMUNOLOGY 2014; 192:5529-39. [PMID: 24808370 DOI: 10.4049/jimmunol.1400021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RNA export factor germinal center-associated nuclear protein (GANP) interacts with activation-induced cytidine deaminase (AID) and shepherds it from the cytoplasm to the nucleus and toward the IgV region loci in B cells. In this study, we demonstrate a role for GANP in the repair of AID-initiated DNA damage in chicken DT40 B cells to generate IgV region diversity by gene conversion and somatic hypermutation. GANP plays a positive role in IgV region diversification of DT40 B cells in a nonhomologous end joining-proficient state. DNA-PKcs physically interacts with GANP, and this interaction is dissociated by dsDNA breaks induced by a topoisomerase II inhibitor, etoposide, or AID overexpression. GANP affects the choice of DNA repair mechanism in B cells toward homologous recombination rather than nonhomologous end joining repair. Thus, GANP presumably plays a critical role in protection of the rearranged IgV loci by favoring homologous recombination of the DNA breaks under accelerated AID recruitment.
Collapse
Affiliation(s)
- Mohammed Mansour Abbas Eid
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Kazuhiko Maeda
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Sarah Ameen Almofty
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Shailendra Kumar Singh
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Mayuko Shimoda
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Nobuo Sakaguchi
- Department of Immunology, Graduate School of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| |
Collapse
|
17
|
Lee S, Liu X, Takeda S, Choi K. Genotoxic potentials and related mechanisms of bisphenol A and other bisphenol compounds: a comparison study employing chicken DT40 cells. CHEMOSPHERE 2013; 93:434-440. [PMID: 23791112 DOI: 10.1016/j.chemosphere.2013.05.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/30/2013] [Accepted: 05/05/2013] [Indexed: 06/02/2023]
Abstract
Bisphenol A (BPA) has been found in plastic food containers, paper currencies and toys. BPA has been reported for various adverse health concerns including reproduction, development and carcinogenesis. These potential health implications have led to increasing use of alternative bisphenols such as bisphenol F and bisphenol S among many. However, little is known about the toxicity of alternative bisphenols and most of the toxicological information is limited to endocrine disrupting potentials. In this study, we evaluated cytotoxicity and the genotoxic potentials of several bisphenol compounds, and identified the mechanism of genotoxicity using a panel of mutant chicken DT40 cell lines deficient in DNA repair pathways. Several bisphenols including bisphenol AP, bisphenol M, or bisphenol P exerted genotoxic potentials that are greater than that of BPA. Generally RAD54(-/-) mutant cells were the most sensitive to all bisphenols except for bisphenol F, suggesting the induction of DNA double-strand breaks that could be rescued by homologous recombination. Genotoxic potential of bisphenols was confirmed by chromosomal aberration assay and γ-H2AX foci forming assay between wild-type and RAD54(-/-) mutant. Among the tested bisphenols, BPP at 12.5μM showed the greatest genotoxic potency, inducing chromosomal aberration and γ-H2AX foci in RAD54(-/-) mutant by 2.6 and 4.8 folds greater than those in wild-type, respectively. Our results clearly show several alternative bisphenols can cause genotoxicity that could be rescued by homologous recombination pathway, and some bisphenols induced even greater genotoxic potentials than that of BPA.
Collapse
Affiliation(s)
- Sangwoo Lee
- School of Public Health, Seoul National University, Seoul 151-742, Republic of Korea
| | | | | | | |
Collapse
|
18
|
Campo VA, Patenaude AM, Kaden S, Horb L, Firka D, Jiricny J, Di Noia JM. MSH6- or PMS2-deficiency causes re-replication in DT40 B cells, but it has little effect on immunoglobulin gene conversion or on repair of AID-generated uracils. Nucleic Acids Res 2013; 41:3032-46. [PMID: 23314153 PMCID: PMC3597665 DOI: 10.1093/nar/gks1470] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The mammalian antibody repertoire is shaped by somatic hypermutation (SHM) and class switch recombination (CSR) of the immunoglobulin (Ig) loci of B lymphocytes. SHM and CSR are triggered by non-canonical, error-prone processing of G/U mismatches generated by activation-induced deaminase (AID). In birds, AID does not trigger SHM, but it triggers Ig gene conversion (GC), a ‘homeologous’ recombination process involving the Ig variable region and proximal pseudogenes. Because recombination fidelity is controlled by the mismatch repair (MMR) system, we investigated whether MMR affects GC in the chicken B cell line DT40. We show here that Msh6−/− and Pms2−/− DT40 cells display cell cycle defects, including genomic re-replication. However, although IgVλ GC tracts in MMR-deficient cells were slightly longer than in normal cells, Ig GC frequency, donor choice or the number of mutations per sequence remained unaltered. The finding that the avian MMR system, unlike that of mammals, does not seem to contribute towards the processing of G/U mismatches in vitro could explain why MMR is unable to initiate Ig GC in this species, despite initiating SHM and CSR in mammalian cells. Moreover, as MMR does not counteract or govern Ig GC, we report a rare example of ‘homeologous’ recombination insensitive to MMR.
Collapse
Affiliation(s)
- Vanina A Campo
- Institut de Recherches Cliniques de Montréal, Division of Immunity and Viral Infections, Montréal, H2W 1R7 Québec, Canada
| | | | | | | | | | | | | |
Collapse
|
19
|
Rousseau L, Etienne O, Roque T, Desmaze C, Haton C, Mouthon MA, Bernardino-Sgherri J, Essers J, Kanaar R, Boussin FD. In vivo importance of homologous recombination DNA repair for mouse neural stem and progenitor cells. PLoS One 2012; 7:e37194. [PMID: 22666344 PMCID: PMC3362579 DOI: 10.1371/journal.pone.0037194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 04/18/2012] [Indexed: 01/15/2023] Open
Abstract
We characterized the in vivo importance of the homologous recombination factor RAD54 for the developing mouse brain cortex in normal conditions or after ionizing radiation exposure. Contrary to numerous homologous recombination genes, Rad54 disruption did not impact the cortical development without exogenous stress, but it dramatically enhanced the radiation sensitivity of neural stem and progenitor cells. This resulted in the death of all cells irradiated during S or G2, whereas the viability of cells irradiated in G1 or G0 was not affected by Rad54 disruption. Apoptosis occurred after long arrests at intra-S and G2/M checkpoints. This concerned every type of neural stem and progenitor cells, showing that the importance of Rad54 for radiation response was linked to the cell cycle phase at the time of irradiation and not to the differentiation state. In the developing brain, RAD54-dependent homologous recombination appeared absolutely required for the repair of damages induced by ionizing radiation during S and G2 phases, but not for the repair of endogenous damages in normal conditions. Altogether our data support the existence of RAD54-dependent and -independent homologous recombination pathways.
Collapse
Affiliation(s)
- Laure Rousseau
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Olivier Etienne
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Telma Roque
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Chantal Desmaze
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Céline Haton
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Marc-André Mouthon
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
| | - Jacqueline Bernardino-Sgherri
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
- Laboratoire de Gamétogenèse, Apoptose et Génotoxicité, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
| | - Jeroen Essers
- Department of Cell Biology & Genetics, Cancer Genomics Center, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
- Department of Vascular Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Cell Biology & Genetics, Cancer Genomics Center, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | - François D. Boussin
- Laboratoire de Radiopathologie, SCSR, iRCM, DSV, CEA, Fontenay-aux-Roses, France
- U967, INSERM, Fontenay-aux-Roses, France
- UMR 967, Université Paris Diderot, Sorbonne Paris Cité, Fontenay-aux-Roses, France
- UMR 967, Université Paris Sud, Fontenay-aux-Roses, France
- * E-mail:
| |
Collapse
|
20
|
Liu X, Lee J, Ji K, Takeda S, Choi K. Potentials and mechanisms of genotoxicity of six pharmaceuticals frequently detected in freshwater environment. Toxicol Lett 2012; 211:70-6. [DOI: 10.1016/j.toxlet.2012.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 03/07/2012] [Accepted: 03/07/2012] [Indexed: 01/22/2023]
|
21
|
Sale JE. Competition, collaboration and coordination--determining how cells bypass DNA damage. J Cell Sci 2012; 125:1633-43. [PMID: 22499669 DOI: 10.1242/jcs.094748] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cells must overcome replication blocks that might otherwise lead to genomic instability or cell death. Classical genetic experiments have identified a series of mechanisms that cells use to replicate damaged DNA: translesion synthesis, template switching and homologous recombination. In translesion synthesis, DNA lesions are replicated directly by specialised DNA polymerases, a potentially error-prone approach. Template switching and homologous recombination use an alternative undamaged template to allow the replicative polymerases to bypass DNA lesions and, hence, are generally error free. Classically, these pathways have been viewed as alternatives, competing to ensure replication of damaged DNA templates is completed. However, this view of a series of static pathways has been blurred by recent work using a combination of genetic approaches and methodology for examining the physical intermediates of bypass reactions. These studies have revealed a much more dynamic interaction between the pathways than was initially appreciated. In this Commentary, I argue that it might be more helpful to start thinking of lesion-bypass mechanisms in terms of a series of dynamically assembled 'modules', often comprising factors from different classical pathways, whose deployment is crucially dependent on the context in which the bypass event takes place.
Collapse
Affiliation(s)
- Julian E Sale
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| |
Collapse
|
22
|
Campi M, D’Andrea L, Emiliani J, Casati P. Participation of chromatin-remodeling proteins in the repair of ultraviolet-B-damaged DNA. PLANT PHYSIOLOGY 2012; 158:981-95. [PMID: 22170978 PMCID: PMC3271783 DOI: 10.1104/pp.111.191452] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 12/14/2011] [Indexed: 05/17/2023]
Abstract
The genome of plants is organized into chromatin, affecting the rates of transcription, DNA recombination, and repair. In this work, we have investigated the consequences of reduced expression of some chromatin-remodeling factors and histone acetylation in maize (Zea mays) and Arabidopsis (Arabidopsis thaliana) in their participation in DNA repair after ultraviolet (UV)-B irradiation. Plants deficient in NFC102/NFC4 or SDG102/SDG26 showed more damaged DNA than wild-type plants; however, the Arabidopsis chc1 mutant showed similar accumulation of cyclobutane pyrimidine dimers as wild-type plants, in contrast to the increased DNA damage measured in the maize chc101 RNA interference line. In Arabidopsis, plants deficient in chromatin remodeling are also affected in the accumulation of pigments by UV-B. Plants treated with an inhibitor of histone acetyltransferases, curcumin, previous to the UV-B treatment show deficiencies in DNA repair; in addition, the chromatin remodeling-deficient plants have altered levels of acetylated histones after the UV-B treatment, demonstrating that histone acetylation is important during DNA repair in these two plant species. Arabidopsis mutants ham1 and ham2 also showed increased DNA damage after UV-B, suggesting that the role of these proteins in DNA damage repair has been conserved through evolution. However, cyclobutane pyrimidine dimer accumulation was higher in ham1 than in ham2; suggesting that HAM1 has a major role in DNA repair after UV-B. In summary, in this work, we have demonstrated that chromatin remodeling, and histone acetylation in particular, is important during DNA repair by UV-B, demonstrating that both genetic and epigenetic effects control DNA repair in plants.
Collapse
Affiliation(s)
| | | | | | - Paula Casati
- Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, 2000 Rosario, Argentina
| |
Collapse
|
23
|
Amunugama R, Fishel R. Homologous Recombination in Eukaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:155-206. [DOI: 10.1016/b978-0-12-387665-2.00007-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
24
|
Sale JE. Measurement of diversification in the immunoglobulin light chain gene of DT40 cells. Methods Mol Biol 2012; 920:417-32. [PMID: 22941620 DOI: 10.1007/978-1-61779-998-3_29] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The immunoglobulin loci of the genetically tractable chicken B cell line DT40 provide a unique opportunity to study the cellular response to endogenously generated DNA damage in a chromosomal context. Abasic sites generated by the concerted action of Activation-Induced Deaminase (AID) and Uracil DNA Glycosylase result in both homologous recombination-dependent gene conversion and translesion synthesis-dependent point mutations. The system has provided important insights into both the early stages of AID-dependent immunoglobulin gene diversification and into the relationship between pathways of DNA damage bypass. Here we describe the assays that can be employed to monitor the rate and pattern of immunoglobulin gene diversification at the light chain locus of DT40.
Collapse
Affiliation(s)
- Julian E Sale
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| |
Collapse
|
25
|
Fujinaka Y, Matsuoka K, Iimori M, Tuul M, Sakasai R, Yoshinaga K, Saeki H, Morita M, Kakeji Y, Gillespie DA, Yamamoto KI, Takata M, Kitao H, Maehara Y. ATR-Chk1 signaling pathway and homologous recombinational repair protect cells from 5-fluorouracil cytotoxicity. DNA Repair (Amst) 2011; 11:247-58. [PMID: 22188649 DOI: 10.1016/j.dnarep.2011.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 11/20/2011] [Accepted: 11/25/2011] [Indexed: 11/18/2022]
Abstract
5-Fluorouracil (5-FU) has long been a mainstay antimetabolite chemotherapeutic drug for the treatment of major solid tumors, particularly colorectal cancer. 5-FU is processed intracellularly to yield active metabolites that compromise RNA and DNA metabolism. However, the mechanisms responsible for its cytotoxicity are not fully understood. From the phenotypic analysis of mutant chicken B lymphoma DT40 cells, we found that homologous recombinational repair (HRR), involving Rad54 and BRCA2, and the ATR-Chk1 signaling pathway, involving Rad9 and Rad17, significantly contribute to 5-FU tolerance. 5-FU induced γH2AX nuclear foci, which were colocalized with the key HRR factor Rad51, but not with DNA double-strand breaks (DSBs), in a dose-dependent manner as cells accumulated in the S phase. Inhibition of Chk1 kinase by UCN-01 increased 5-FU-induced γH2AX and enhanced 5-FU cytotoxicity not only in wild-type cells but also in Rad54- or BRCA2-deficient cells, suggesting that HRR and Chk1 kinase have non-overlapping roles in 5-FU tolerance. 5-FU-induced Chk1 phosphorylation was significantly impaired in Rad9- or Rad17-deficient cells, and severe γH2AX nuclear foci and DSBs were formed, which was followed by apoptosis. Finally, inhibition of Chk1 kinase by UCN-01 increased 5-FU-induced γH2AX nuclear foci and enhanced 5-FU cytotoxicity in Rad9- or Rad17-deficient cells. These results suggest that Rad9- and Rad17-independent activation of the ATR-Chk1 signaling pathway also significantly contributes to 5-FU tolerance.
Collapse
Affiliation(s)
- Yoshihiko Fujinaka
- Department of Molecular Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Sarkies P, Murat P, Phillips LG, Patel KJ, Balasubramanian S, Sale JE. FANCJ coordinates two pathways that maintain epigenetic stability at G-quadruplex DNA. Nucleic Acids Res 2011; 40:1485-98. [PMID: 22021381 PMCID: PMC3287192 DOI: 10.1093/nar/gkr868] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We have previously reported that DT40 cells deficient in the Y-family polymerase REV1 are defective in replicating G-quadruplex DNA. In vivo this leads to uncoupling of DNA synthesis from redeposition of histones displaced ahead of the replication fork, which in turn leads to loss of transcriptional repression due to failure to recycle pre-existing repressive histone post-translational modifications. Here we report that a similar process can also affect transcriptionally active genes, leading to their deactivation. We use this finding to develop an assay based on loss of expression of a cell surface marker to monitor epigenetic instability at the level of single cells. This assay allows us to demonstrate G4 DNA motif-associated epigenetic instability in mutants of three helicases previously implicated in the unwinding of G-quadruplex structures, FANCJ, WRN and BLM. Transcriptional profiling of DT40 mutants reveals that FANCJ coordinates two independent mechanisms to maintain epigenetic stability near G4 DNA motifs that are dependent on either REV1 or on the WRN and BLM helicases, suggesting a model in which efficient in vivo replication of G-quadruplexes often requires the established 5'-3'-helicase activity of FANCJ acting in concert with either a specialized polymerase or helicase operating in the opposite polarity.
Collapse
Affiliation(s)
- Peter Sarkies
- Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | | | | | | | | | | |
Collapse
|
27
|
Hoot SJ, Zheng X, Potenski CJ, White TC, Klein HL. The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity. BMC Microbiol 2011; 11:214. [PMID: 21951709 PMCID: PMC3197502 DOI: 10.1186/1471-2180-11-214] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 09/27/2011] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC), can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH) at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans. RESULTS The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility. CONCLUSIONS Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.
Collapse
Affiliation(s)
- Samantha J Hoot
- Department of Biochemistry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | | | | | | | | |
Collapse
|
28
|
Ceballos SJ, Heyer WD. Functions of the Snf2/Swi2 family Rad54 motor protein in homologous recombination. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1809:509-23. [PMID: 21704205 PMCID: PMC3171615 DOI: 10.1016/j.bbagrm.2011.06.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 05/27/2011] [Accepted: 06/06/2011] [Indexed: 11/25/2022]
Abstract
Homologous recombination is a central pathway to maintain genomic stability and is involved in the repair of DNA damage and replication fork support, as well as accurate chromosome segregation during meiosis. Rad54 is a dsDNA-dependent ATPase of the Snf2/Swi2 family of SF2 helicases, although Rad54 lacks classical helicase activity and cannot carry out the strand displacement reactions typical for DNA helicases. Rad54 is a potent and processive motor protein that translocates on dsDNA, potentially executing several functions in recombinational DNA repair. Rad54 acts in concert with Rad51, the central protein of recombination that performs the key reactions of homology search and DNA strand invasion. Here, we will review the role of the Rad54 protein in homologous recombination with an emphasis on mechanistic studies with the yeast and human enzymes. We will discuss how these results relate to in vivo functions of Rad54 during homologous recombination in somatic cells and during meiosis. This article is part of a Special Issue entitled: Snf2/Swi2 ATPase structure and function.
Collapse
Affiliation(s)
- Shannon J. Ceballos
- Department of Microbiology, University of California, Davis, Davis, CA 95616-8665
| | - Wolf-Dietrich Heyer
- Department of Microbiology, University of California, Davis, Davis, CA 95616-8665
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616-8665
| |
Collapse
|
29
|
Yamamoto KN, Hirota K, Kono K, Takeda S, Sakamuru S, Xia M, Huang R, Austin CP, Witt KL, Tice RR. Characterization of environmental chemicals with potential for DNA damage using isogenic DNA repair-deficient chicken DT40 cell lines. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:547-61. [PMID: 21538559 PMCID: PMC3278799 DOI: 10.1002/em.20656] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/02/2011] [Indexed: 05/23/2023]
Abstract
Included among the quantitative high throughput screens (qHTS) conducted in support of the US Tox21 program are those being evaluated for the detection of genotoxic compounds. One such screen is based on the induction of increased cytotoxicity in seven isogenic chicken DT40 cell lines deficient in DNA repair pathways compared to the parental DNA repair-proficient cell line. To characterize the utility of this approach for detecting genotoxic compounds and identifying the type(s) of DNA damage induced, we evaluated nine of 42 compounds identified as positive for differential cytotoxicity in qHTS (actinomycin D, adriamycin, alachlor, benzotrichloride, diglycidyl resorcinol ether, lovastatin, melphalan, trans-1,4-dichloro-2-butene, tris(2,3-epoxypropyl)isocyanurate) and one non-cytotoxic genotoxic compound (2-aminothiamine) for (1) clastogenicity in mutant and wild-type cells; (2) the comparative induction of γH2AX positive foci by melphalan; (3) the extent to which a 72-hr exposure duration increased assay sensitivity or specificity; (4) the use of 10 additional DT40 DNA repair-deficient cell lines to better analyze the type(s) of DNA damage induced; and (5) the involvement of reactive oxygen species in the induction of DNA damage. All compounds but lovastatin and 2-aminothiamine were more clastogenic in at least one DNA repair-deficient cell line than the wild-type cells. The differential responses across the various DNA repair-deficient cell lines provided information on the type(s) of DNA damage induced. The results demonstrate the utility of this DT40 screen for detecting genotoxic compounds, for characterizing the nature of the DNA damage, and potentially for analyzing mechanisms of mutagenesis.
Collapse
Affiliation(s)
- Kimiyo N Yamamoto
- Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
The epistatic relationship between BRCA2 and the other RAD51 mediators in homologous recombination. PLoS Genet 2011; 7:e1002148. [PMID: 21779174 PMCID: PMC3136442 DOI: 10.1371/journal.pgen.1002148] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 05/02/2011] [Indexed: 02/06/2023] Open
Abstract
RAD51 recombinase polymerizes at the site of double-strand breaks (DSBs) where it performs DSB repair. The loss of RAD51 causes extensive chromosomal breaks, leading to apoptosis. The polymerization of RAD51 is regulated by a number of RAD51 mediators, such as BRCA1, BRCA2, RAD52, SFR1, SWS1, and the five RAD51 paralogs, including XRCC3. We here show that brca2-null mutant cells were able to proliferate, indicating that RAD51 can perform DSB repair in the absence of BRCA2. We disrupted the BRCA1, RAD52, SFR1, SWS1, and XRCC3 genes in the brca2-null cells. All the resulting double-mutant cells displayed a phenotype that was very similar to that of the brca2-null cells. We suggest that BRCA2 might thus serve as a platform to recruit various RAD51 mediators at the appropriate position at the DNA–damage site. Mutations in BRCA1 and BRCA2 predispose hereditary breast and ovarian cancer. Such mutations sensitize to chemotherapeutic agents, including camptothecin, cisplatin, and poly(ADP-ribose) polymerase (PARP) inhibitor, since RAD51 mediators including both BRCA proteins promote repair of DNA lesions induced by these drugs. Little is known of the functional relationships among RAD51, BRCA2, and other RAD51 mediators, because no brca2-null cells were available. Furthermore, the phenotype of sws1 mutants has not been documented. We here disrupted every known RAD51 mediator and analyzed the phenotype of the resulting mutants in both BRCA2-deficient and -proficient backgrounds. The understanding of the function of individual RAD51 mediators and their functional interactions will contribute to the accurate prediction of anti-cancer therapy efficacy.
Collapse
|
31
|
Ji K, Choi K, Giesy JP, Musarrat J, Takeda S. Genotoxicity of several polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDEs, and their mechanisms of toxicity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:5003-5008. [PMID: 21545137 DOI: 10.1021/es104344e] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) have been extensively utilized as flame retardants, and recently there has been concern about potential adverse effects in humans and wildlife. Their hydroxylated analogs (OH-BDEs) have received increasing attention due to their potential for endocrine and neurological toxicities. However, the potentials and mechanisms of genotoxicity of these brominated compounds have scarcely been investigated. In the present study, genotoxicity of tetra-BDEs, penta BDE, octa-BDE, deca-BDE, and tetra-OH-BDEs were investigated by use of chicken DT40 cell lines including wild-type cells and a panel of mutant cell lines deficient in DNA repair pathways. Tetra-BDEs have greater genotoxic potential than do the other BDEs tested. OH-tetra-BDEs were more genotoxic than tetra-BDEs. DT40 cells, deficient in base excision repair (Polβ(-/-)) and translesion DNA synthesis (REV3(-/-)) pathways, were hypersensitive to the genotoxic effects of tetra-BDEs and OH-tetra-BDEs. The observation of chromosomal aberrations and gamma-H2AX assay confirmed that the studied brominated compounds caused double strand breaks. Pretreatment with N-acetyl-l-cysteine (NAC) significantly rescued the Polβ(-/-) and REV3(-/-) mutants, which is consistent with the hypothesis that PBDEs and OH-BDEs cause DNA damage mediated through reactive oxygen species (ROS). Some tetra-BDEs and OH-tetra-BDEs caused base damage through ROS leading to replication blockage and subsequent chromosomal breaks.
Collapse
Affiliation(s)
- Kyunghee Ji
- School of Public Health, Seoul National University, Seoul, 151-742, Korea
| | | | | | | | | |
Collapse
|
32
|
Agarwal S, van Cappellen WA, Guénolé A, Eppink B, Linsen SEV, Meijering E, Houtsmuller A, Kanaar R, Essers J. ATP-dependent and independent functions of Rad54 in genome maintenance. ACTA ACUST UNITED AC 2011; 192:735-50. [PMID: 21357745 PMCID: PMC3051825 DOI: 10.1083/jcb.201011025] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Rad54’s ATPase activity does not affect accumulation of homologous recombination proteins in repair foci, but influences its dissociation and that of Rad51. Rad54, a member of the SWI/SNF protein family of DNA-dependent ATPases, repairs DNA double-strand breaks (DSBs) through homologous recombination. Here we demonstrate that Rad54 is required for the timely accumulation of the homologous recombination proteins Rad51 and Brca2 at DSBs. Because replication protein A and Nbs1 accumulation is not affected by Rad54 depletion, Rad54 is downstream of DSB resection. Rad54-mediated Rad51 accumulation does not require Rad54’s ATPase activity. Thus, our experiments demonstrate that SWI/SNF proteins may have functions independent of their ATPase activity. However, quantitative real-time analysis of Rad54 focus formation indicates that Rad54’s ATPase activity is required for the disassociation of Rad54 from DNA and Rad54 turnover at DSBs. Although the non–DNA-bound fraction of Rad54 reversibly interacts with a focus, independent of its ATPase status, the DNA-bound fraction is immobilized in the absence of ATP hydrolysis by Rad54. Finally, we show that ATP hydrolysis by Rad54 is required for the redistribution of DSB repair sites within the nucleus.
Collapse
Affiliation(s)
- Sheba Agarwal
- Department of Cell Biology and Genetics, Cancer Genomics Center, 3000 CA Rotterdam, Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Delacôte F, Perez C, Guyot V, Mikonio C, Potrel P, Cabaniols JP, Delenda C, Pâques F, Duchateau P. Identification of genes regulating gene targeting by a high-throughput screening approach. J Nucleic Acids 2011; 2011:947212. [PMID: 21716659 PMCID: PMC3118287 DOI: 10.4061/2011/947212] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 01/23/2011] [Indexed: 12/29/2022] Open
Abstract
Homologous gene targeting (HGT) is a precise but inefficient process for genome engineering. Several methods for increasing its efficiency have been developed, including the use of rare cutting endonucleases. However, there is still room for improvement, as even nuclease-induced HGT may vary in efficiency as a function of the nuclease, target site, and cell type considered. We have developed a high-throughput screening assay for the identification of factors stimulating meganuclease-induced HGT. We used this assay to explore a collection of siRNAs targeting 19,121 human genes. At the end of secondary screening, we had identified 64 genes for which knockdown affected nuclease-induced HGT. Two of the strongest candidates were characterized further. We showed that siRNAs directed against the ATF7IP gene, encoding a protein involved in chromatin remodeling, stimulated HGT by a factor of three to eight, at various loci and in different cell types. This method thus led to the identification of a number of genes, the manipulation of which might increase rates of targeted recombination.
Collapse
Affiliation(s)
- Fabien Delacôte
- Cellectis SA, 102 Avenue Gaston Roussel, 93340 Romainville Cedex, France
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Roles of vertebrate Smc5 in sister chromatid cohesion and homologous recombinational repair. Mol Cell Biol 2011; 31:1369-81. [PMID: 21245390 DOI: 10.1128/mcb.00786-10] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The structural maintenance of chromosomes (Smc) family members Smc5 and Smc6 are both essential in budding and fission yeasts. Yeast smc5/6 mutants are hypersensitive to DNA damage, and Smc5/6 is recruited to HO-induced double-strand breaks (DSBs), facilitating intersister chromatid recombinational repair. To determine the role of the vertebrate Smc5/6 complex during the normal cell cycle, we generated an Smc5-deficient chicken DT40 cell line using gene targeting. Surprisingly, Smc5(-) cells were viable, although they proliferated more slowly than controls and showed mitotic abnormalities. Smc5-deficient cells were sensitive to methyl methanesulfonate and ionizing radiation (IR) and showed increased chromosome aberration levels upon irradiation. Formation and resolution of Rad51 and gamma-H2AX foci after irradiation were altered in Smc5 mutants, suggesting defects in homologous recombinational (HR) repair of DNA damage. Ku70(-/-) Smc5(-) cells were more sensitive to IR than either single mutant, with Rad54(-/-) Smc5(-) cells being no more sensitive than Rad54(-/-) cells, consistent with an HR function for the vertebrate Smc5/6 complex. Although gene targeting occurred at wild-type levels, recombinational repair of induced double-strand breaks was reduced in Smc5(-) cells. Smc5 loss increased sister chromatid exchanges and sister chromatid separation distances in mitotic chromosomes. We conclude that Smc5/6 regulates recombinational repair by ensuring appropriate sister chromatid cohesion.
Collapse
|
35
|
Kitao H, Hirano S, Takata M. Evaluation of homologous recombinational repair in chicken B lymphoma cell line, DT40. Methods Mol Biol 2011; 745:293-309. [PMID: 21660701 DOI: 10.1007/978-1-61779-129-1_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Homologous recombination (HR) is a mode of double-strand break (DSB) repair required for cell viability in vertebrate cells. Targeted integration of homologous DNA fragment by HR is usually a very rare event in vertebrate cells; however, in chicken B lymphoma cell line DT40, the ratio of targeted to random integration is extremely high. Although the underlying mechanism of this phenotype is not fully understood, DT40 has been utilized as a model cell line for a number of genetic analyses. Here we describe three assays for evaluating homologous recombinational repair (HRR) using DT40 as a model system, measuring gene-targeting frequency, analyzing HRR process of single DSB induced by yeast homing endonuclease I-SceI, and measuring sister chromatid exchange frequency. Combined with generation of gene-disrupted DT40 mutant cell line, these assays have been highly useful to investigate the mechanisms in HRR. Using these techniques, a role of HRR of not only Rad52 epistasis group genes but also genes whose mutation cause hereditary cancer syndrome, such as Fanconi anemia, has been established.
Collapse
Affiliation(s)
- Hiroyuki Kitao
- Department of Molecular Oncology, Kyushu University, Kyushu, Japan.
| | | | | |
Collapse
|
36
|
Abstract
Homologous recombination (HR) performs crucial functions including DNA repair, segregation of homologous chromosomes, propagation of genetic diversity, and maintenance of telomeres. HR is responsible for the repair of DNA double-strand breaks and DNA interstrand cross-links. The process of HR is initiated at the site of DNA breaks and gaps and involves a search for homologous sequences promoted by Rad51 and auxiliary proteins followed by the subsequent invasion of broken DNA ends into the homologous duplex DNA that then serves as a template for repair. The invasion produces a cross-stranded structure, known as the Holliday junction. Here, we describe the properties of Rad54, an important and versatile HR protein that is evolutionarily conserved in eukaryotes. Rad54 is a motor protein that translocates along dsDNA and performs several important functions in HR. The current review focuses on the recently identified Rad54 activities which contribute to the late phase of HR, especially the branch migration of Holliday junctions.
Collapse
Affiliation(s)
- Alexander V Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
| | | | | | | |
Collapse
|
37
|
Wang X, Takenaka K, Takeda S. PTIP promotes DNA double-strand break repair through homologous recombination. Genes Cells 2010; 15:243-54. [DOI: 10.1111/j.1365-2443.2009.01379.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
38
|
Asagoshi K, Tano K, Chastain PD, Adachi N, Sonoda E, Kikuchi K, Koyama H, Nagata K, Kaufman DG, Takeda S, Wilson SH, Watanabe M, Swenberg JA, Nakamura J. FEN1 functions in long patch base excision repair under conditions of oxidative stress in vertebrate cells. Mol Cancer Res 2010; 8:204-15. [PMID: 20145043 DOI: 10.1158/1541-7786.mcr-09-0253] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
From in vitro studies, flap endonuclease 1 (FEN1) has been proposed to play a role in the long patch (LP) base excision repair (BER) subpathway. Yet the role of FEN1 in BER in the context of the living vertebrate cell has not been thoroughly explored. In the present study, we cloned a DT40 chicken cell line with a deletion in the FEN1 gene and found that these FEN1-deficient cells exhibited hypersensitivity to H(2)O(2). This oxidant produces genotoxic lesions that are repaired by BER, suggesting that the cells have a deficiency in BER affecting survival. In experiments with extracts from the isogenic FEN1 null and wild-type cell lines, the LP-BER activity of FEN1 null cells was deficient, whereas repair by the single-nucleotide BER subpathway was normal. Other consequences of the FEN1 deficiency were also evaluated. These results illustrate that FEN1 plays a role in LP-BER in higher eukaryotes, presumably by processing the flap-containing intermediates of BER.
Collapse
Affiliation(s)
- Kenjiro Asagoshi
- Laboratory of Structural Biology, NIEHS, NIH, Research Triangle Park, North Carolina, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Kumari A, Mazina OM, Shinde U, Mazin AV, Lu H. A role for SSRP1 in recombination-mediated DNA damage response. J Cell Biochem 2009; 108:508-18. [PMID: 19639603 DOI: 10.1002/jcb.22280] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A possible role for structure-specific recognition protein 1 (SSRP1) in replication-associated repair processes has previously been suggested based on its interaction with several DNA repair factors and the replication defects observed in SSRP1 mutants. In this study, we investigated the potential role of SSRP1 in association with DNA repair mediated by homologous recombination (HR), one of the pathways involved in repairing replication-associated DNA damage, in mammalian cells. Surprisingly, over-expression of SSRP1 reduced the number of hprt(+) recombinants generated via HR both spontaneously and upon hydroxyurea (HU) treatment, whereas knockdown of SSRP1 resulted in an increase of HR events in response to DNA double-strand break formation. In correlation, we found that the depletion of SSRP1 in HU-treated human cells elevated the number of Rad51 and H2AX foci, while over-expression of the wild-type SSRP1 markedly reduced HU-induced Rad51 foci formation. We also found that SSRP1 physically interacts with a key HR repair protein, Rad54 both in vitro and in vivo. Further, branch migration studies demonstrated that SSRP1 inhibits Rad54-promoted branch migration of Holliday junctions in vitro. Taken together, our data suggest a functional role for SSRP1 in spontaneous and replication-associated DNA damage response by suppressing avoidable HR repair events.
Collapse
Affiliation(s)
- Anuradha Kumari
- Center for Research on Occupational and Environmental Toxicology, Oregon Health and Science University, Portland, Oregon 97239, USA
| | | | | | | | | |
Collapse
|
40
|
Taylor CW, Rahman T, Tovey SC, Dedos SG, Taylor EJA, Velamakanni S. IP3 receptors: some lessons from DT40 cells. Immunol Rev 2009; 231:23-44. [PMID: 19754888 DOI: 10.1111/j.1600-065x.2009.00807.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Inositol-1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca2+ channels that are regulated by IP3 and Ca2+ and are modulated by many additional signals. These properties allow them to initiate and, via Ca2+-induced Ca2+ release, regeneratively propagate Ca2+ signals evoked by receptors that stimulate formation of IP3. The ubiquitous expression of IP3R highlights their importance, but it also presents problems when attempting to resolve the behavior of defined IP3R. DT40 cells are a pre-B-lymphocyte cell line in which high rates of homologous recombination afford unrivalled opportunities to disrupt endogenous genes. DT40-knockout cells with both alleles of each of the three IP3R genes disrupted provide the only null-background for analysis of homogenous recombinant IP3R. We review the properties of DT40 cells and consider three areas where they have contributed to understanding IP3R behavior. Patch-clamp recording from the nuclear envelope and Ca2+ release from intracellular stores loaded with a low-affinity Ca2+ indicator address the mechanisms leading to activation of IP(3)R. We show that IP3 causes intracellular IP3R to cluster and re-tune their responses to IP3 and Ca2+, better equipping them to mediate regenerative Ca2+ signals. Finally, we show that DT40 cells reliably count very few IP3R into the plasma membrane, where they mediate about half the Ca2+ entry evoked by the B-cell antigen receptor.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
| | | | | | | | | | | |
Collapse
|
41
|
Singh P, Marikkannu R, Bitomsky N, Klempnauer KH. Disruption of the Pdcd4 tumor suppressor gene in chicken DT40 cells reveals its role in the DNA-damage response. Oncogene 2009; 28:3758-64. [PMID: 19684621 DOI: 10.1038/onc.2009.239] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The programmed cell death gene 4 (Pdcd4) gene has been implicated as a new tumor suppressor gene in the development of several types of human cancer. Pdcd4 interacts with the translation initiation factor, eIF4A, and is thought to act as a translation inhibitor. Here, we have used the chicken B-cell line DT40 to disrupt the Pdcd4 gene by homologous recombination. Our study shows that cells lacking a functional Pdcd4 gene are viable and have no obvious defects when cultivated under normal growth conditions. However, Pdcd4 knockout cells show an increased sensitivity to agents that cause DNA damage, such as UV light, etoposide or ethyl-methanesulfonate. In summary, our findings show that Pdcd4 has an important function in the cellular response to DNA damage. Low Pdcd4 expression, which is frequently observed in tumor cells, might therefore contribute to tumorigenesis by disturbing the cellular DNA-damage response.
Collapse
Affiliation(s)
- P Singh
- Institute for Biochemistry, Westfälische-Wilhelms-Universität Münster, Münster, Germany
| | | | | | | |
Collapse
|
42
|
Okamoto N, Okamoto M, Araki S, Arakawa H, Mizuta R, Kitamura D. Possible contribution of DNase γ to immunoglobulin V gene diversification. Immunol Lett 2009; 125:22-30. [DOI: 10.1016/j.imlet.2009.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Revised: 05/11/2009] [Accepted: 05/24/2009] [Indexed: 11/16/2022]
|
43
|
Boyko A, Matsuoka A, Kovalchuk I. High frequency Agrobacterium tumefaciens-mediated plant transformation induced by ammonium nitrate. PLANT CELL REPORTS 2009; 28:737-57. [PMID: 19221758 DOI: 10.1007/s00299-009-0676-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 01/13/2009] [Accepted: 01/25/2009] [Indexed: 05/07/2023]
Abstract
Success in plant genetic transformation depends on the efficiency of explant regeneration and transgene integration. Whereas the former one depends on explant totipotency, the latter depends on the activity of host DNA repair and chromatin organisation factors. We analyzed whether factors that result in an increase in recombination frequency can also increase transformation efficiency. Here, we report that a threefold increase in the concentration of NH(4)NO(3) in the growth medium results in more than a threefold increase in the Agrobacterium tumefaciens-mediated transformation frequency of Nicotiana tabacum plants. Regeneration of calli without selection showed that the increase in transformation frequency was primarily due to the increase in transgene integration efficiency rather than in tissue regeneration efficiency. PCR analysis of insertion sites showed a decrease in the frequency of truncations of the T-DNA right border and an increase on the left border. We hypothesize that exposure to ammonium nitrate modifies the activity of host factors leading to higher frequency of transgene integrations and possibly to the shift in the mechanism of transgene integrations.
Collapse
Affiliation(s)
- Alex Boyko
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Canada
| | | | | |
Collapse
|
44
|
Arakawa H, Buerstedde JM. Activation-induced cytidine deaminase-mediated hypermutation in the DT40 cell line. Philos Trans R Soc Lond B Biol Sci 2009; 364:639-44. [PMID: 19008193 DOI: 10.1098/rstb.2008.0202] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Depending on the species and the developmental stage of B cells, activation-induced cytidine deaminase (AID) triggers immunoglobulin (Ig) gene diversification by gene conversion, hypermutation or switch recombination. The bursal B cell line DT40 usually diversifies its rearranged Ig light chain (IgL) gene by gene conversion, but disruption of the RAD51 gene paralogues or deletion of the psiV conversion donors induces hypermutation. Although not all aspects of somatic hypermutation can be studied in DT40, the compact size of the chicken IgL locus and the ability to modify the genome by targeted integration are powerful experimental advantages. We review here how the studies in DT40 contributed to understanding how AID initiates Ig gene diversification and how AID-induced uracils are subsequently processed by uracil DNA glycosylase, proliferating cell nuclear antigens and error-prone polymerases. We also discuss the on-going research on the Ig locus specificity of hypermutation and the possibility of using hypermutation for the artificial evolution of proteins and regulatory sequences in DT40.
Collapse
Affiliation(s)
- Hiroshi Arakawa
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute for Molecular Radiobiology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | | |
Collapse
|
45
|
Takata M, Ishiai M, Kitao H. The Fanconi anemia pathway: insights from somatic cell genetics using DT40 cell line. Mutat Res 2009; 668:92-102. [PMID: 19622405 DOI: 10.1016/j.mrfmmm.2008.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 12/15/2008] [Accepted: 12/24/2008] [Indexed: 10/21/2022]
Abstract
The Fanconi anemia (FA) pathway is a complex phosphorylation-ubiquitination network in the DNA damage signaling, which is still poorly understood. Defects in the "FA pathway" or in the related DNA repair proteins cause FA, a hereditary disorder that accompanies compromised DNA crosslink repair, poor hematopoetic stem cell survival, genomic instability, and cancer. For molecular dissection of the FA pathway, we have been using chicken B cell line DT40 as a model system. In this review, we will summarize our current understanding of the pathway, and discuss how studies using DT40 have contributed to this rapidly evolving field.
Collapse
Affiliation(s)
- Minoru Takata
- Laboratory of DNA Damage Signaling, Department of Late Effect Studies, Radiation Biology Center, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto 606-8501, Japan.
| | | | | |
Collapse
|
46
|
Lee SA, Roques C, Magwood AC, Masson JY, Baker MD. Recovery of deficient homologous recombination in Brca2-depleted mouse cells by wild-type Rad51 expression. DNA Repair (Amst) 2008; 8:170-81. [PMID: 18992372 DOI: 10.1016/j.dnarep.2008.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 08/11/2008] [Accepted: 10/01/2008] [Indexed: 01/15/2023]
Abstract
The BRCA2 tumor suppressor is important in maintaining genomic stability. BRCA2 is proposed to control the availability, cellular localization and DNA binding activity of the central homologous recombination protein, RAD51, with loss of BRCA2 resulting in defective homologous recombination. Nevertheless, the roles of BRCA2 in regulating RAD51 and how other proteins implicated in RAD51 regulation, such as RAD52 and RAD54 function relative to BRCA2 is not known. In this study, we tested whether defective homologous recombination in Brca2-depleted mouse hybridoma cells could be rectified by expression of mouse Rad51 or the Rad51-interacting mouse proteins, Rad52 and Rad54. In the Brca2-depleted cells, defective homologous recombination can be restored by over-expression of wild-type mouse Rad51, but not mouse Rad52 or Rad54. Correction of the homologous recombination defect requires Rad51 ATPase activity. A sizeable fraction ( approximately 50%) of over-expressed wild-type Rad51 is nuclear localized. The restoration of homologous recombination in the presence of a low (i.e., non-functional) level of Brca2 by wild-type Rad51 over-expression is unexpected. We suggest that Rad51 may access the nuclear compartment in a Brca2-independent manner and when Rad51 is over-expressed, the normal requirement for Brca2 control over Rad51 function in homologous recombination is dispensable. Our studies support loss of Rad51 function as a critical underlying factor in the homologous recombination defect in the Brca2-depleted cells.
Collapse
Affiliation(s)
- Shauna A Lee
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1 Canada
| | | | | | | | | |
Collapse
|
47
|
Holloman WK, Schirawski J, Holliday R. The homologous recombination system of Ustilago maydis. Fungal Genet Biol 2008; 45 Suppl 1:S31-9. [PMID: 18502156 PMCID: PMC2583931 DOI: 10.1016/j.fgb.2008.04.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Revised: 04/09/2008] [Accepted: 04/11/2008] [Indexed: 12/26/2022]
Abstract
Homologous recombination is a high fidelity, template-dependent process that is used in repair of damaged DNA, recovery of broken replication forks, and disjunction of homologous chromosomes in meiosis. Much of what is known about recombination genes and mechanisms comes from studies on baker's yeast. Ustilago maydis, a basidiomycete fungus, is distant evolutionarily from baker's yeast and so offers the possibility of gaining insight into recombination from an alternative perspective. Here we have surveyed the genome of U. maydis to determine the composition of its homologous recombination system. Compared to baker's yeast, there are fundamental differences in the function as well as in the repertoire of dedicated components. These include the use of a BRCA2 homolog and its modifier Dss1 rather than Rad52 as a mediator of Rad51, the presence of only a single Rad51 paralog, and the absence of Dmc1 and auxiliary meiotic proteins.
Collapse
Affiliation(s)
- William K Holloman
- Cornell University Weill Medical College, Department of Microbiology and Immunology, NY 10021, USA.
| | | | | |
Collapse
|
48
|
Abstract
Chicken DT40 cells deficient in the 9-1-1 checkpoint clamp exhibit hypersensitivity to a variety of DNA-damaging agents. Although recent work suggests that, in addition to its role in checkpoint activation, this complex may play a role in homologous recombination and translesion synthesis, the cause of this hypersensitivity has not been studied thoroughly. The immunoglobulin locus of DT40 cells allows monitoring of homologous recombination and translesion synthesis initiated by activation-induced deaminase (AID)-dependent abasic sites. We show that both the RAD9(-/-) and RAD17(-/-) mutants exhibit substantially reduced immunoglobulin gene conversion. However, the level of nontemplated immunoglobulin point mutation increased in these mutants, a finding that is reminiscent of the phenotype resulting from the loss of RAD51 paralogs or Brca2. This suggests that the 9-1-1 complex does not play a central role in translesion synthesis in this context. Despite reduced immunoglobulin gene conversion, the RAD9(-/-) and RAD17(-/-) cells do not exhibit a prominent defect in double-strand break-induced gene conversion or a sensitivity to camptothecin. This suggests that the roles of Rad9 and Rad17 may be confined to a subset of homologous recombination reactions initiated by replication-stalling lesions rather than those associated with double-strand break repair.
Collapse
|
49
|
Neiman PE, Elsaesser K, Loring G, Kimmel R. Myc oncogene-induced genomic instability: DNA palindromes in bursal lymphomagenesis. PLoS Genet 2008; 4:e1000132. [PMID: 18636108 PMCID: PMC2444050 DOI: 10.1371/journal.pgen.1000132] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 06/18/2008] [Indexed: 12/16/2022] Open
Abstract
Genetic instability plays a key role in the formation of naturally occurring cancer. The formation of long DNA palindromes is a rate-limiting step in gene amplification, a common form of tumor-associated genetic instability. Genome-wide analysis of palindrome formation (GAPF) has detected both extensive palindrome formation and gene amplification, beginning early in tumorigenesis, in an experimental Myc-induced model tumor system in the chicken bursa of Fabricius. We determined that GAPF-detected palindromes are abundant and distributed nonrandomly throughout the genome of bursal lymphoma cells, frequently at preexisting short inverted repeats. By combining GAPF with chromatin immunoprecipitation (ChIP), we found a significant association between occupancy of gene-proximal Myc binding sites and the formation of palindromes. Numbers of palindromic loci correlate with increases in both levels of Myc over-expression and ChIP-detected occupancy of Myc binding sites in bursal cells. However, clonal analysis of chick DF-1 fibroblasts suggests that palindrome formation is a stochastic process occurring in individual cells at a small number of loci relative to much larger numbers of susceptible loci in the cell population and that the induction of palindromes is not involved in Myc-induced acute fibroblast transformation. GAPF-detected palindromes at the highly oncogenic bic/miR-155 locus in all of our preneoplastic and neoplastic bursal samples, but not in DNA from normal and other transformed cell types. This finding indicates very strong selection during bursal lymphomagenesis. Therefore, in addition to providing a platform for gene copy number change, palindromes may alter microRNA genes in a fashion that can contribute to cancer development.
Collapse
MESH Headings
- Animals
- Bursa of Fabricius/pathology
- Cell Line, Transformed
- Cell Line, Tumor
- Cell Transformation, Neoplastic
- Cell Transformation, Viral
- Chickens
- Chromatin Immunoprecipitation
- DNA, Complementary
- DNA, Neoplasm/genetics
- Gene Amplification
- Genes, myc
- Genetic Vectors
- Genomic Instability
- Lymphoma, B-Cell/etiology
- Lymphoma, B-Cell/genetics
- Nucleic Acid Hybridization
- Oligonucleotide Array Sequence Analysis
- Precancerous Conditions/genetics
- Repetitive Sequences, Nucleic Acid
- Retroviridae/genetics
- Stochastic Processes
Collapse
Affiliation(s)
- Paul E Neiman
- Division of Basic Science, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
| | | | | | | |
Collapse
|
50
|
Abe T, Ishiai M, Hosono Y, Yoshimura A, Tada S, Adachi N, Koyama H, Takata M, Takeda S, Enomoto T, Seki M. KU70/80, DNA-PKcs, and Artemis are essential for the rapid induction of apoptosis after massive DSB formation. Cell Signal 2008; 20:1978-85. [PMID: 18674614 DOI: 10.1016/j.cellsig.2008.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 07/05/2008] [Accepted: 07/07/2008] [Indexed: 02/06/2023]
Abstract
KU70(-/-) and DNA-PKcs(-/-/-)chicken DT40 cells are reportedly highly sensitive to the DNA topoisomerase II inhibitor etoposide. Here we report that KU70 and DNA-PKcs unexpectedly function together during the induction of apoptosis after exposure to high levels of etoposide. In the presence of 100 microM etoposide, apoptosis was induced within 1 h in wild type DT40 cells but not in KU70(-/-) and DNA-PKcs(-/-/-) cells. In addition, the DNA-PK inhibitors NU7026 and wortmannin, as well as the caspase inhibitor Z-VAD-FMK, inhibited etoposide-induced apoptosis in wild type cells. Although Artemis(-/-) cells also showed defects in the etoposide-induced apoptosis, the other mutants defective in nonhomologous end-joining (NHEJ), LIG4(-/-), XRCC4(-), and XLF(-/-) cells were capable to induce apoptosis. When cells were treated with high doses of etoposide, the chromatin binding of DNA-PKcs was impaired by deletion of KU70 but not of Artemis, suggesting that KU70 acts upstream of DNA-PKcs and Artemis acts downstream of DNA-PKcs in the apoptotic pathway like the NHEJ pathway. These results suggest that the proteins involved in the early stage of NHEJ pathway including Artemis but not the downstream factors decide the cell fate by selecting apoptosis or DNA repair according to the degree of DNA damage.
Collapse
Affiliation(s)
- Takuya Abe
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|