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Horan TS, Ascenção CFR, Mellor C, Wang M, Smolka MB, Cohen PE. The DNA helicase FANCJ (BRIP1) functions in double strand break repair processing, but not crossover formation during prophase I of meiosis in male mice. PLoS Genet 2024; 20:e1011175. [PMID: 38377115 PMCID: PMC10906868 DOI: 10.1371/journal.pgen.1011175] [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: 11/16/2023] [Revised: 03/01/2024] [Accepted: 02/07/2024] [Indexed: 02/22/2024] Open
Abstract
Meiotic recombination between homologous chromosomes is initiated by the formation of hundreds of programmed double-strand breaks (DSBs). Approximately 10% of these DSBs result in crossovers (COs), sites of physical DNA exchange between homologs that are critical to correct chromosome segregation. Virtually all COs are formed by coordinated efforts of the MSH4/MSH5 and MLH1/MLH3 heterodimers, the latter representing the defining marks of CO sites. The regulation of CO number and position is poorly understood, but undoubtedly requires the coordinated action of multiple repair pathways. In a previous report, we found gene-trap disruption of the DNA helicase, FANCJ (BRIP1/BACH1), elicited elevated numbers of MLH1 foci and chiasmata. In somatic cells, FANCJ interacts with numerous DNA repair proteins including MLH1, and we hypothesized that FANCJ functions with MLH1 to regulate the major CO pathway. To further elucidate the meiotic function of FANCJ, we produced three new Fancj mutant mouse lines via CRISPR/Cas9 gene editing: a full-gene deletion, truncation of the N-terminal Helicase domain, and a C-terminal dual-tagged allele. We also generated an antibody against the C-terminus of the mouse FANCJ protein. Surprisingly, none of our Fancj mutants show any change in either MLH1 focus counts during pachynema or total CO number at diakinesis of prophase I. We find evidence that FANCJ and MLH1 do not interact in meiosis; further, FANCJ does not co-localize with MSH4, MLH1, or MLH3 in meiosis. Instead, FANCJ co-localizes with BRCA1 and TOPBP1, forming discrete foci along the chromosome cores beginning in early meiotic prophase I and densely localized to unsynapsed chromosome axes in late zygonema and to the XY chromosomes in early pachynema. Fancj mutants also exhibit a subtle persistence of DSBs in pachynema. Collectively, these data indicate a role for FANCJ in early DSB repair, but they rule out a role for FANCJ in MLH1-mediated CO events.
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Affiliation(s)
- Tegan S. Horan
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, New York, United States of America
| | - Carolline F. R. Ascenção
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, New York, United States of America
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Christopher Mellor
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Meng Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Marcus B. Smolka
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, New York, United States of America
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Paula E. Cohen
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, New York, United States of America
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2
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Horan TS, Ascenção CFR, Mellor CA, Wang M, Smolka MB, Cohen PE. The DNA helicase FANCJ (BRIP1) functions in Double Strand Break repair processing, but not crossover formation during Prophase I of meiosis in male mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.06.561296. [PMID: 37873301 PMCID: PMC10592954 DOI: 10.1101/2023.10.06.561296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
During meiotic prophase I, recombination between homologous parental chromosomes is initiated by the formation of hundreds of programmed double-strand breaks (DSBs), each of which must be repaired with absolute fidelity to ensure genome stability of the germline. One outcome of these DSB events is the formation of Crossovers (COs), the sites of physical DNA exchange between homologs that are critical to ensure the correct segregation of parental chromosomes. However, COs account for only a small (~10%) proportion of all DSB repair events; the remaining 90% are repaired as non-crossovers (NCOs), most by synthesis dependent strand annealing. Virtually all COs are formed by coordinated efforts of the MSH4/MSH5 and MLH1/MLH3 heterodimers. The number and positioning of COs is exquisitely controlled via mechanisms that remain poorly understood, but which undoubtedly require the coordinated action of multiple repair pathways downstream of the initiating DSB. In a previous report we found evidence suggesting that the DNA helicase and Fanconi Anemia repair protein, FANCJ (BRIP1/BACH1), functions to regulate meiotic recombination in mouse. A gene-trap disruption of Fancj showed an elevated number of MLH1 foci and COs. FANCJ is known to interact with numerous DNA repair proteins in somatic cell repair contexts, including MLH1, BLM, BRCA1, and TOPBP1, and we hypothesized that FANCJ regulates CO formation through a direct interaction with MLH1 to suppress the major CO pathway. To further elucidate the function of FANCJ in meiosis, we produced three new Fancj mutant mouse lines via CRISPR/Cas9 gene editing: a full-gene deletion, a mutant line lacking the MLH1 interaction site and the N-terminal region of the Helicase domain, and a C-terminal 6xHIS-HA dual-tagged allele of Fancj. We also generated an antibody against the C-terminus of the mouse FANCJ protein. Surprisingly, while Fanconi-like phenotypes are observed within the somatic cell lineages of the full deletion Fancj line, none of the Fancj mutants show any change in either MLH1 focus counts during pachynema or total CO number at diakinesis of prophase I of meiosis. We find evidence that FANCJ and MLH1 do not interact in meiosis; further, FANCJ does not co-localize with MSH4, MLH1, or MLH3 during late prophase I. Instead, FANCJ forms discrete foci along the chromosome cores beginning in early meiotic prophase I, occasionally co-localizing with MSH4, and then becomes densely localized on unsynapsed chromosome axes in late zygonema and to the XY chromosomes in early pachynema. Strikingly, this localization strongly overlaps with BRCA1 and TOPBP1. Fancj mutants also exhibit a subtle persistence of DSBs in pachynema. Collectively, these data suggest a role for FANCJ in early DSB repair events, and possibly in the formation of NCOs, but they rule out a role for FANCJ in MLH1-mediated CO events. Thus, the role of FANCJ in meiotic cells involves different pathways and different interactors to those described in somatic cell lineages.
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Affiliation(s)
- Tegan S Horan
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, NY 14853
| | - Carolline F R Ascenção
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, NY 14853
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | | | - Meng Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853
| | - Marcus B Smolka
- Cornell Reproductive Sciences Center, Cornell University, Ithaca, NY 14853
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Paula E Cohen
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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3
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Clay DE, Jezuit EA, Montague RA, Fox DT. Conserved function of Drosophila Fancd2 monoubiquitination in response to double-strand DNA breaks. G3 (BETHESDA, MD.) 2022; 12:6589893. [PMID: 35595243 PMCID: PMC9339327 DOI: 10.1093/g3journal/jkac129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/12/2022] [Indexed: 11/12/2022]
Abstract
Fanconi anemia genes play key roles in metazoan DNA damage responses, and human FA mutations cause numerous disease phenotypes. In human cells, activating monoubiquitination of the Fanconi anemia protein Fancd2 occurs following diverse DNA damage stimuli. Monoubiquitinated Fancd2 forms nuclear foci to recruit additional repair factors. Fancd2 animal models to date have focused on molecular nulls or whole gene knockdown, leaving the specific in vivo role of monoubiquitination unclear. Using a point mutant in a conserved residue, we recently linked Drosophila Fancd2 monoubiquitination to a mitosis-specific DNA double-strand break response. In this context, we used CRISPR/Cas9 to generate the first animal model of an endogenous mutation in the conserved monoubiquitination site (fancd2K595R). Here, we expand upon our characterization of fancd2K595R. We also introduce and characterize additional Drosophila tools to study fancd2, including new mutant alleles and GFP-tagged rescue transgenes. Using these new reagents, we show the impact of Drosophila Fancd2 on organismal and cell viability, as well as on repair protein localization, in the presence or absence of double-strand breaks. These findings expand our understanding of Fanconi anemia gene function in vivo and provide useful reagents for DNA repair research.
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Affiliation(s)
- Delisa E Clay
- Department of Pharmacology and Cancer Biology, C318 Levine Science Research Center, Duke University Medical School, Durham, NC 27710, USA
| | - Erin A Jezuit
- Department of Pharmacology and Cancer Biology, C318 Levine Science Research Center, Duke University Medical School, Durham, NC 27710, USA
| | - Ruth A Montague
- Department of Pharmacology and Cancer Biology, C318 Levine Science Research Center, Duke University Medical School, Durham, NC 27710, USA
| | - Donald T Fox
- Corresponding author: Department of Pharmacology and Cancer Biology, C318 Levine Science Research Center, DUMC Box 3813, Duke University Medical School, Durham, NC 27710, USA.
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4
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Athar F, Templeman NM. C. elegans as a model organism to study female reproductive health. Comp Biochem Physiol A Mol Integr Physiol 2022; 266:111152. [PMID: 35032657 DOI: 10.1016/j.cbpa.2022.111152] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 12/17/2022]
Abstract
Female reproductive health has been historically understudied and underfunded. Here, we present the advantages of using a free-living nematode, Caenorhabditis elegans, as an animal system to study fundamental aspects of female reproductive health. C. elegans is a powerful high-throughput model organism that shares key genetic and physiological similarities with humans. In this review, we highlight areas of pressing medical and biological importance in the 21st century within the context of female reproductive health. These include the decline in female reproductive capacity with increasing chronological age, reproductive dysfunction arising from toxic environmental insults, and cancers of the reproductive system. C. elegans has been instrumental in uncovering mechanistic insights underlying these processes, and has been valuable for developing and testing therapeutics to combat them. Adopting a convenient model organism such as C. elegans for studying reproductive health will encourage further research into this field, and broaden opportunities for making advancements into evolutionarily conserved mechanisms that control reproductive function.
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Affiliation(s)
- Faria Athar
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Nicole M Templeman
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada.
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Germoglio M, Adamo A, Incerti G, Cartenì F, Gigliotti S, Storlazzi A, Mazzoleni S. Self-DNA Exposure Induces Developmental Defects and Germline DNA Damage Response in Caenorhabditis elegans. BIOLOGY 2022; 11:biology11020262. [PMID: 35205128 PMCID: PMC8869574 DOI: 10.3390/biology11020262] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 02/06/2023]
Abstract
Simple Summary All organisms, from bacteria to mammals, activate responses protecting themselves from dangers represented by outsider invaders and damages. Inappropriately localised self-DNA is one of the molecular clues detected as a danger and triggering defence reactions that may lead to chronic activation of inflammatory conditions. In this study, we investigate if dietary delivered self-DNA is detrimental in a simple metazoan model organism, the nematode Caenorhabditis elegans. Adverse effects were observed in the progenies of worms exposed to self-DNA integrated into their bacterial diet. The presence of self-DNA in the food significantly decreased egg deposition, induced high embryo death, and negatively affected larval development. The findings, on the one side, raise interesting questions on the basic molecular mechanisms involved in response to extracellular self-DNA. On the other side, the observed phenomenon suggests possible applications for the biocontrol of parasitic nematodes by appropriate delivery of their self-DNA in their growing environment. Abstract All organisms, from bacteria to mammals, sense and respond to foreign nucleic acids to fight infections in order to survive and preserve genome integrity across generations. The innate immune system is an evolutionarily conserved defence strategy. Complex organisms have developed various cellular processes to respond to and recognise not only infections, i.e., pathogen-associated molecular patterns (PAMPs), but also to sense injury and tissue dysfunctions, i.e., damage-associated molecular patterns (DAMPs). Mis-localized self-DNA can be sensed as DAMP by specific DNA-sensing pathways, and self-DNA chronic exposure can be detrimental to the organisms. Here, we investigate the effects of dietary delivered self-DNA in the nematode Caenorhabditis elegans. The hermaphrodite worms were fed on Escherichia coli genomic libraries: a C. elegans library (self) and a legume (Medicago truncatula) library (non-self). We show that the self-library diet affects embryogenesis, larval development and gametogenesis. DNA damage and activation of p53/CEP-1-dependent apoptosis occur in gonadal germ cells. Studies of self-DNA exposure in this model organism were not pursued up to now. The genetic tractability of C. elegans will help to identify the basic molecular pathways involved in such mechanisms. The specificity of the adverse effects associated with a self-DNA enriched diet suggests applications in biological pest control approaches.
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Affiliation(s)
- Marcello Germoglio
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Guido Incerti
- Department of Agri-Food, Animal and Environmental Sciences (DI4A), University of Udine, 33100 Udine, Italy;
| | - Fabrizio Cartenì
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
| | - Silvia Gigliotti
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Aurora Storlazzi
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
- Correspondence: (A.S.); (S.M.)
| | - Stefano Mazzoleni
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
- Correspondence: (A.S.); (S.M.)
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6
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Xu L, Xu W, Li D, Yu X, Gao F, Qin Y, Yang Y, Zhao S. FANCI plays an essential role in spermatogenesis and regulates meiotic histone methylation. Cell Death Dis 2021; 12:780. [PMID: 34373449 PMCID: PMC8353022 DOI: 10.1038/s41419-021-04034-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 12/15/2022]
Abstract
FANCI is an essential component of Fanconi anemia pathway, which is responsible for the repair of DNA interstrand cross-links (ICLs). As an evolutionarily related partner of FANCD2, FANCI functions together with FANCD2 downstream of FA core complex. Currently, growing evidences showed that the essential role of FA pathway in male fertility. However, the underlying mechanisms for FANCI in regulating spermatogenesis remain unclear. In the present study, we found that the male Fanci−/− mice were sterile and exhibited abnormal spermatogenesis, including massive germ cell apoptosis in seminiferous tubules and dramatically decreased number of sperms in epididymis. Besides, FANCI deletion impaired maintenance of undifferentiated spermatogonia. Further investigation indicated that FANCI was essential for FANCD2 foci formation and regulated H3K4 and H3K9 methylation on meiotic sex chromosomes. These findings elucidate the role and mechanism of FANCI during spermatogenesis in mice and provide new insights into the etiology and molecular basis of nonobstructive azoospermia.
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Affiliation(s)
- Lan Xu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China
| | - Weiwei Xu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China
| | - Duan Li
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China
| | - Xiaoxia Yu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China
| | - Fei Gao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Yingying Qin
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China
| | - Yajuan Yang
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China. .,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China. .,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China. .,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China. .,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China. .,State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China. .,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
| | - Shidou Zhao
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China. .,Key laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, Shandong, 250012, China. .,Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong, 250012, China. .,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong, 250012, China. .,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong, 250012, China.
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7
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Animal models of Fanconi anemia: A developmental and therapeutic perspective on a multifaceted disease. Semin Cell Dev Biol 2021; 113:113-131. [PMID: 33558144 DOI: 10.1016/j.semcdb.2020.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/17/2020] [Accepted: 11/18/2020] [Indexed: 12/31/2022]
Abstract
Fanconi anemia (FA) is a genetic disorder characterized by developmental abnormalities, progressive bone marrow failure, and increased susceptibility to cancer. FA animal models have been useful to understand the pathogenesis of the disease. Herein, we review FA developmental models that have been developed to simulate human FA, focusing on zebrafish and mouse models. We summarize the recapitulated phenotypes observed in these in vivo models including bone, gametogenesis and sterility defects, as well as marrow failure. We also discuss the relevance of aldehydes in pathogenesis of FA, emphasizing on hematopoietic defects. In addition, we provide a summary of potential therapeutic agents, such as aldehyde scavengers, TGFβ inhibitors, and gene therapy for FA. The diversity of FA animal models makes them useful for understanding FA etiology and allows the discovery of new therapies.
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8
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Santonicola P, Germoglio M, d'Abbusco DS, Adamo A. Functional characterization of Caenorhabditis elegans cbs-2 gene during meiosis. Sci Rep 2020; 10:20913. [PMID: 33262405 PMCID: PMC7708620 DOI: 10.1038/s41598-020-78006-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/18/2020] [Indexed: 11/19/2022] Open
Abstract
Cystathionine β-synthase (CBS) is a eukaryotic enzyme that maintains the cellular homocysteine homeostasis and catalyzes the conversion of homocysteine to L-cystathionine and Hydrogen sulfide, via the trans-sulfuration pathway. In Caenorhabditis elegans, two cbs genes are present: cbs-1 functions similarly as to human CBS, and cbs-2, whose roles are instead unknown. In the present study we performed a phenotypic characterization of the cbs-2 mutant. The null cbs-2 mutant is viable, fertile and shows the wild-type complement of six bivalents in most oocyte nuclei, which is indicative of a correct formation of crossover recombination. In absence of synaptonemal complex formation (syp-2 mutant), loss of cbs-2 leads to chromosome fragmentation, suggesting that cbs-2 is essential during inter-sister repair. Interestingly, although proficient in the activation of the DNA damage checkpoint after exposure to genotoxic stress, the cbs-2 mutant is defective in DNA damage-induced apoptosis in meiotic germ cells. These results suggest possible functions for CBS-2 in meiosis, distinct from a role in the trans-sulfuration pathway. We propose that the C. elegans CBS-2 protein is required for both inter-sister repair and execution of DNA damage-induced apoptosis.
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Affiliation(s)
- Pamela Santonicola
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131, Naples, Italy
| | - Marcello Germoglio
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131, Naples, Italy
| | - Domenico Scotto d'Abbusco
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131, Naples, Italy
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131, Naples, Italy.
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9
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Oh S, Bae W, Alfhili MA, Lee MH. Nucleotide Excision Repair, XPA-1, and the Translesion Synthesis Complex, POLZ-1 and REV-1, Are Critical for Interstrand Cross-Link Repair in Caenorhabditis elegans Germ Cells. Biochemistry 2020; 59:3554-3561. [PMID: 32945661 DOI: 10.1021/acs.biochem.0c00719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Interstrand cross-links (ICLs) are adducts of covalently linked nucleotides in opposing DNA strands that obstruct replication and prime cells for malignant transformation or premature cell death. ICLs may be caused by alkylating agents or ultraviolet (UV) irradiation. These toxic lesions are removed by diverse repair mechanisms such as the Fanconi anemia (FA) pathway, nucleotide excision repair (NER), translesion synthesis (TLS), and homologous recombination (HR). In mammals, the xeroderma pigmentosum group F (XP-F) protein participates in both the FA pathway and NER, while DNA polymerase ζ (POLZ-1) and REV-1 mediate TLS. Nevertheless, little is known regarding the genetic determinants of these pathways in ICL repair and damage tolerance in germ cells. In this study, we examined the sensitivity of Caenorhabditis elegans germ cells to ICLs generated by trimethylpsoralen/ultraviolet A (TMP/UV-A) combination, and embryonic mortality was employed as a surrogate for DNA damage in germ cells. Our results show that XPA-1, POLZ-1, and REV-1 were more critical than FA pathway mediators in preserving genomic stability in C. elegans germ cells. Notably, mutant worms lacking both XPA-1 and POLZ-1 (or REV-1) were more sensitive to ICLs compared to either single mutant alone. Moreover, knockdown of XPA-1 and REV-1 leads to the retarded disappearance of RPA-1 and RAD-51 foci upon ICL damage. Since DNA repair mechanisms are broadly conserved, our findings may have ramifications for prospective therapeutic interventions in humans.
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Affiliation(s)
- Sinae Oh
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, 03772 Seoul, South Korea
| | - Woori Bae
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, 03772 Seoul, South Korea
| | - Mohammad A Alfhili
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Myon Hee Lee
- Department of Internal Medicine, Hematology/Oncology Division, Brody School of Medicine at East Carolina University, Greenville, North Carolina 27834, United States
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