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Thomas R, Zaksauskaite R, Al-Kandari N, Hyde A, Abugable A, El-Khamisy S, van Eeden F. Second generation lethality in RNAseH2a knockout zebrafish. Nucleic Acids Res 2024; 52:11014-11028. [PMID: 39217460 PMCID: PMC11472149 DOI: 10.1093/nar/gkae725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 07/31/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024] Open
Abstract
Removal of ribonucleotides from DNA by RNaseH2 is essential for genome stability, and its impacted function causes the neurodegenerative disease, Aicardi Goutières Syndrome. We have created a zebrafish rnaseh2a mutant to model this process. Surprisingly, RNaseH2a knockouts show little phenotypic abnormality at adulthood in the first generation, unlike mouse knockout models, which are early embryonic lethal. However, the second generation offspring show reduced development, increased ribonucleotide incorporation and upregulation of key inflammatory markers, resulting in both maternal and paternal embryonic lethality. Thus, neither fathers or mothers can generate viable offspring even when crossed to wild-type partners. Despite their survival, rnaseh2a-/- adults show an accumulation of ribonucleotides in both the brain and testes that is not present in early development. Our data suggest that homozygotes possess RNaseH2 independent compensatory mechanisms that are inactive or overwhelmed by the inherited ribonucleotides in their offspring, or that zebrafish have a yet unknown tolerance mechanism. Additionally, we identify ribodysgenesis, the rapid removal of rNMPs and subsequently lethal fragmentation of DNA as responsible for maternal and paternal embryonic lethality.
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Affiliation(s)
- Ruth C Thomas
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Ringaile Zaksauskaite
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Norah Y Al-Kandari
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Anne Cathrine Hyde
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Arwa A Abugable
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Sherif F El-Khamisy
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
- The Institute of Cancer Therapeutics, University of Bradford, BD7 1DP, UK
| | - Freek J van Eeden
- Bateson Centre, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Healthy Lifespan Institute, Sheffield Institute for Neuroscience, University of Sheffield, Sheffield S10 2TN, UK
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Malathion alters the transcription of target genes of the tumour suppressor tp53 and cancerous processes in Colossoma macropomum: Mechanisms of DNA damage response, oxidative stress and apoptosis. Chem Biol Interact 2023; 374:110405. [PMID: 36796534 DOI: 10.1016/j.cbi.2023.110405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
Different classes of pesticides such as fungicides, herbicides, and insecticides, can induce differential expression of genes that are involved in tumorigenesis events in fish, including the expression of tumor suppressor tp53. The degree and duration of the stressful condition is decisive in defining which tp53-dependent pathway will be activated. Herein we evaluate the target genes expression that participates in the regulation pathway of the tumor suppressor tp53 and in the cancerous processes in tambaqui after exposure to malathion. Our hypothesis is that malathion promotes a gene response that is differentially regulated over time, with positive regulation of tp53 target genes related to the apoptotic pathway and a negative regulation of genes that promote antioxidant responses. The fish were exposed to a sublethal concentration of the insecticide for 6 and 48 h. Liver samples were used to analyze the expression of 11 genes using real-time PCR. Overall, the malathion promoted over time increases in tp53 expression and differential expression of tp53 related genes. The exposure resulted in the activation of damage response related genes, caused a positive expression of atm/atr genes. The pro-apoptotic gene bax was up-regulated and the anti-apoptotic bcl2 was down-regulated. Increased expression of mdm2 and sesn1 in the first hours of exposure and no effect on the antioxidant genes sod2 and gpx1 were also observed. We also witnessed an increase in the expression of the hif-1α gene, with no effect on ras proto-oncogene. The extension of this stressful condition accentuated tp53 transcription, and minimized the levels of mdm2, sens1 and bax; however, it down regulated the levels of bcl2 and the bcl2/bax ratio, which indicates the maintenance of the apoptotic response to the detriment of an antioxidant response.
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Acharya N, Singh KP. Recent advances in the molecular basis of chemotherapy resistance and potential application of epigenetic therapeutics in chemorefractory renal cell carcinoma. WIREs Mech Dis 2022; 14:e1575. [DOI: 10.1002/wsbm.1575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/11/2022] [Accepted: 06/22/2022] [Indexed: 12/13/2022]
Affiliation(s)
- Narayan Acharya
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH) Texas Tech University Lubbock Texas USA
| | - Kamaleshwar P. Singh
- Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH) Texas Tech University Lubbock Texas USA
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Kobar K, Collett K, Prykhozhij SV, Berman JN. Zebrafish Cancer Predisposition Models. Front Cell Dev Biol 2021; 9:660069. [PMID: 33987182 PMCID: PMC8112447 DOI: 10.3389/fcell.2021.660069] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/23/2021] [Indexed: 12/11/2022] Open
Abstract
Cancer predisposition syndromes are rare, typically monogenic disorders that result from germline mutations that increase the likelihood of developing cancer. Although these disorders are individually rare, resulting cancers collectively represent 5-10% of all malignancies. In addition to a greater incidence of cancer, affected individuals have an earlier tumor onset and are frequently subjected to long-term multi-modal cancer screening protocols for earlier detection and initiation of treatment. In vivo models are needed to better understand tumor-driving mechanisms, tailor patient screening approaches and develop targeted therapies to improve patient care and disease prognosis. The zebrafish (Danio rerio) has emerged as a robust model for cancer research due to its high fecundity, time- and cost-efficient genetic manipulation and real-time high-resolution imaging. Tumors developing in zebrafish cancer models are histologically and molecularly similar to their human counterparts, confirming the validity of these models. The zebrafish platform supports both large-scale random mutagenesis screens to identify potential candidate/modifier genes and recently optimized genome editing strategies. These techniques have greatly increased our ability to investigate the impact of certain mutations and how these lesions impact tumorigenesis and disease phenotype. These unique characteristics position the zebrafish as a powerful in vivo tool to model cancer predisposition syndromes and as such, several have already been created, including those recapitulating Li-Fraumeni syndrome, familial adenomatous polyposis, RASopathies, inherited bone marrow failure syndromes, and several other pathogenic mutations in cancer predisposition genes. In addition, the zebrafish platform supports medium- to high-throughput preclinical drug screening to identify compounds that may represent novel treatment paradigms or even prevent cancer evolution. This review will highlight and synthesize the findings from zebrafish cancer predisposition models created to date. We will discuss emerging trends in how these zebrafish cancer models can improve our understanding of the genetic mechanisms driving cancer predisposition and their potential to discover therapeutic and/or preventative compounds that change the natural history of disease for these vulnerable children, youth and adults.
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Affiliation(s)
- Kim Kobar
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Keon Collett
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | | | - Jason N. Berman
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada
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