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Gioia M, Payero L, Salim S, Fajish V. G, Farnaz AF, Pannafino G, Chen JJ, Ajith VP, Momoh S, Scotland M, Raghavan V, Manhart CM, Shinohara A, Nishant KT, Alani E. Exo1 protects DNA nicks from ligation to promote crossover formation during meiosis. PLoS Biol 2023; 21:e3002085. [PMID: 37079643 PMCID: PMC10153752 DOI: 10.1371/journal.pbio.3002085] [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: 11/25/2022] [Revised: 05/02/2023] [Accepted: 03/17/2023] [Indexed: 04/21/2023] Open
Abstract
In most sexually reproducing organisms crossing over between chromosome homologs during meiosis is essential to produce haploid gametes. Most crossovers that form in meiosis in budding yeast result from the biased resolution of double Holliday junction (dHJ) intermediates. This dHJ resolution step involves the actions of Rad2/XPG family nuclease Exo1 and the Mlh1-Mlh3 mismatch repair endonuclease. Here, we provide genetic evidence in baker's yeast that Exo1 promotes meiotic crossing over by protecting DNA nicks from ligation. We found that structural elements in Exo1 that interact with DNA, such as those required for the bending of DNA during nick/flap recognition, are critical for its role in crossing over. Consistent with these observations, meiotic expression of the Rad2/XPG family member Rad27 partially rescued the crossover defect in exo1 null mutants, and meiotic overexpression of Cdc9 ligase reduced the crossover levels of exo1 DNA-binding mutants to levels that approached the exo1 null. In addition, our work identified a role for Exo1 in crossover interference. Together, these studies provide experimental evidence for Exo1-protected nicks being critical for the formation of meiotic crossovers and their distribution.
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Affiliation(s)
- Michael Gioia
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Lisette Payero
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Sagar Salim
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum, India
| | - Ghanim Fajish V.
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Amamah F. Farnaz
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum, India
| | - Gianno Pannafino
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Jun Jie Chen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - V. P. Ajith
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum, India
| | - Sherikat Momoh
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Michelle Scotland
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Vandana Raghavan
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Carol M. Manhart
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - K. T. Nishant
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum, India
- Center for High-Performance Computing, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum, India
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
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Li Y, Li X, Cournoyer P, Choudhuri S, Yu X, Guo L, Chen S. Cannabidiol-induced transcriptomic changes and cellular senescence in human Sertoli cells. Toxicol Sci 2023; 191:227-238. [PMID: 36519830 PMCID: PMC10123764 DOI: 10.1093/toxsci/kfac131] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cannabidiol (CBD), one of the major cannabinoids in the plant Cannabis sativa L., is the active ingredient in a drug approved for the treatment of seizures associated with certain childhood-onset epileptic disorders. CBD has been shown to induce male reproductive toxicity in multiple animal models. We previously reported that CBD inhibits cellular proliferation in the mouse Sertoli cell line TM4 and in primary human Sertoli cells. In this study, using a transcriptomic approach with mRNA-sequencing analysis, we identified molecular mechanisms underlying CBD-induced cytotoxicity in primary human Sertoli cells. Analysis of differentially expressed genes demonstrated that DNA replication, cell cycle, and DNA repair were the most significantly affected pathways. We confirmed the concentration-dependent changes in the expression of key genes in these pathways using real-time PCR. mRNA sequencing showed upregulation of a group of genes tightly associated with the senescence-associated secretory phenotype (SASP) and with the activation of the p53 signaling pathway, a key upstream event in cellular senescence. Prolonged treatment of 10 μM CBD-induced cellular senescence, as evidenced by the stable cessation of proliferation and the activation of senescence-associated β-galactosidase (SA-β-gal), 2 hallmarks of senescence. Additionally, using real-time PCR and Western blotting assays, we observed that CBD treatment increased the expression of p16, an important marker of cellular senescence. Taken together, our results show that CBD exposure disturbs various interrelated signaling pathways and induces cellular senescence in primary human Sertoli cells.
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Affiliation(s)
- Yuxi Li
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Xilin Li
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | | | - Supratim Choudhuri
- Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD 20740, USA
| | - Xiaozhong Yu
- College of Nursing, University of New Mexico, Albuquerque, NM 87131, USA
| | - Lei Guo
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Si Chen
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
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Wieser TA, Wuttke DS. Replication Protein A Utilizes Differential Engagement of Its DNA-Binding Domains to Bind Biologically Relevant ssDNAs in Diverse Binding Modes. Biochemistry 2022; 61:2592-2606. [PMID: 36278947 PMCID: PMC9798700 DOI: 10.1021/acs.biochem.2c00504] [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] [Indexed: 12/31/2022]
Abstract
Replication protein A (RPA) is a ubiquitous ssDNA-binding protein that functions in many DNA processing pathways to maintain genome integrity. Recent studies suggest that RPA forms a highly dynamic complex with ssDNA that can engage with DNA in many modes that are orchestrated by the differential engagement of the four DNA-binding domains (DBDs) in RPA. To understand how these modes influence RPA interaction with biologically relevant ligands, we performed a comprehensive and systematic evaluation of RPA's binding to a diverse set of ssDNA ligands that varied in sequence, length, and structure. These equilibrium binding data show that WT RPA binds structured ssDNA ligands differently from its engagement with minimal ssDNAs. Next, we investigated each DBD's contributions to RPA's binding modes through mutation of conserved, functionally important aromatic residues. Mutations in DBD-A and -B have a much larger effect on binding when ssDNA is embedded into DNA secondary structures compared to their association with unstructured minimal ssDNA. As our data support a complex interplay of binding modes, it is critical to define the trimer core DBDs' role in binding these biologically relevant ligands. We found that DBD-C is important for engaging DNA with diverse binding modes, including, unexpectedly, at short ssDNAs. Thus, RPA uses its constituent DBDs to bind biologically diverse ligands in unanticipated ways. These findings lead to a better understanding of how RPA carries out its functions at diverse locations of the genome and suggest a mechanism through which dynamic recognition can impact differential downstream outcomes.
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Affiliation(s)
- Thomas A Wieser
- Department of Biochemistry, University of Colorado Boulder, Jennie Smoly Caruthers Biotechnology Building, UCB 596, Boulder, Colorado80309, United States
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado Boulder, Jennie Smoly Caruthers Biotechnology Building, UCB 596, Boulder, Colorado80309, United States
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Yan S, Gao S, Zhou P. Multi-functions of exonuclease 1 in DNA damage response and cancer susceptibility. RADIATION MEDICINE AND PROTECTION 2021. [DOI: 10.1016/j.radmp.2021.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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