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Ghodke-Puranik Y, Olferiev M, Crow MK. Systemic lupus erythematosus genetics: insights into pathogenesis and implications for therapy. Nat Rev Rheumatol 2024; 20:635-648. [PMID: 39232240 DOI: 10.1038/s41584-024-01152-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2024] [Indexed: 09/06/2024]
Abstract
Systemic lupus erythematosus (SLE) is a prime example of how the interplay between genetic and environmental factors can trigger systemic autoimmunity, particularly in young women. Although clinical disease can take years to manifest, risk is established by the unique genetic makeup of an individual. Genome-wide association studies have identified almost 200 SLE-associated risk loci, yet unravelling the functional effect of these loci remains a challenge. New analytic tools have enabled researchers to delve deeper, leveraging DNA sequencing and cell-specific and immune pathway analysis to elucidate the immunopathogenic mechanisms. Both common genetic variants and rare non-synonymous mutations can interact to increase SLE risk. Notably, variants strongly associated with SLE are often located in genome super-enhancers that regulate MHC class II gene expression. Additionally, the 3D conformations of DNA and RNA contribute to genome regulation and innate immune system activation. Improved therapies for SLE are urgently needed and current and future knowledge from genetic and genomic research should provide new tools to facilitate patient diagnosis, enhance the identification of therapeutic targets and optimize testing of agents.
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Affiliation(s)
- Yogita Ghodke-Puranik
- Mary Kirkland Center for Lupus Research, Hospital for Special Surgery and Weill Cornell Medicine, New York, NY, USA
| | - Mikhail Olferiev
- Mary Kirkland Center for Lupus Research, Hospital for Special Surgery and Weill Cornell Medicine, New York, NY, USA
| | - Mary K Crow
- Mary Kirkland Center for Lupus Research, Hospital for Special Surgery and Weill Cornell Medicine, New York, NY, USA.
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2
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Wan MC, Jiao K, Zhu YN, Wan QQ, Zhang YP, Niu LZ, Lei C, Song JH, Lu WC, Liu HJ, Ren ZY, Tay F, Niu LN. Bacteria-mediated resistance of neutrophil extracellular traps to enzymatic degradation drives the formation of dental calculi. Nat Biomed Eng 2024; 8:1177-1190. [PMID: 38491329 DOI: 10.1038/s41551-024-01186-7] [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: 12/11/2022] [Accepted: 02/06/2024] [Indexed: 03/18/2024]
Abstract
Dental calculi can cause gingival bleeding and periodontitis, yet the mechanism underlying the formation of such mineral build-ups, and in particular the role of the local microenvironment, are unclear. Here we show that the formation of dental calculi involves bacteria in local mature biofilms converting the DNA in neutrophil extracellular traps (NETs) from being degradable by the enzyme DNase I to being degradation resistant, promoting the nucleation and growth of apatite. DNase I inhibited NET-induced mineralization in vitro and ex vivo, yet plasma DNases were ineffective at inhibiting ectopic mineralization in the oral cavity in rodents. The topical application of the DNA-intercalating agent chloroquine in rodents fed with a dental calculogenic diet reverted NET DNA to its degradable form, inhibiting the formation of calculi. Our findings may motivate therapeutic strategies for the reduction of the prevalence of the deposition of bacteria-driven calculi in the oral cavity.
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Affiliation(s)
- Mei-Chen Wan
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Kai Jiao
- Department of Stomatology, Tangdu hospital; State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Yi-Na Zhu
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Qian-Qian Wan
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Yi-Peng Zhang
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Long-Zhang Niu
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Chen Lei
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Jing-Han Song
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Wei-Cheng Lu
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Hua-Jie Liu
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Zhao-Yang Ren
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China
| | - Franklin Tay
- The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Li-Na Niu
- State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.
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Bowden LC, Finlinson J, Jones B, Berges BK. Beyond the double helix: the multifaceted landscape of extracellular DNA in Staphylococcus aureus biofilms. Front Cell Infect Microbiol 2024; 14:1400648. [PMID: 38903938 PMCID: PMC11188362 DOI: 10.3389/fcimb.2024.1400648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/17/2024] [Indexed: 06/22/2024] Open
Abstract
Staphylococcus aureus forms biofilms consisting of cells embedded in a matrix made of proteins, polysaccharides, lipids, and extracellular DNA (eDNA). Biofilm-associated infections are difficult to treat and can promote antibiotic resistance, resulting in negative healthcare outcomes. eDNA within the matrix contributes to the stability, growth, and immune-evasive properties of S. aureus biofilms. eDNA is released by autolysis, which is mediated by murein hydrolases that access the cell wall via membrane pores formed by holin-like proteins. The eDNA content of S. aureus biofilms varies among individual strains and is influenced by environmental conditions, including the presence of antibiotics. eDNA plays an important role in biofilm development and structure by acting as an electrostatic net that facilitates protein-cell and cell-cell interactions. Because of eDNA's structural importance in biofilms and its ubiquitous presence among S. aureus isolates, it is a potential target for therapeutics. Treatment of biofilms with DNase can eradicate or drastically reduce them in size. Additionally, antibodies that target DNABII proteins, which bind to and stabilize eDNA, can also disperse biofilms. This review discusses the recent literature on the release, structure, and function of eDNA in S. aureus biofilms, in addition to a discussion of potential avenues for targeting eDNA for biofilm eradication.
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Affiliation(s)
| | | | | | - Bradford K. Berges
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
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Hofer LK, Jurcisek JA, Elmaraghy C, Goodman SD, Bakaletz LO. Z-Form Extracellular DNA in Pediatric CRS May Provide a Mechanism for Recalcitrance to Treatment. Laryngoscope 2024; 134:1564-1571. [PMID: 37597166 PMCID: PMC10875147 DOI: 10.1002/lary.30986] [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: 05/19/2023] [Revised: 07/21/2023] [Accepted: 08/09/2023] [Indexed: 08/21/2023]
Abstract
OBJECTIVES We examined sinus mucosal samples recovered from pediatric chronic rhinosinusitis (CRS) patients for the presence of Z-form extracellular DNA (eDNA) due to its recently elucidated role in pathogenesis of disease. Further, we immunolabeled these specimens for the presence of both members of the bacterial DNA-binding DNABII protein family, integration host factor (IHF) and histone-like protein (HU), due to their known role in converting common B-DNA to the rare Z-form. METHODS Sinus mucosa samples recovered from 20 patients during functional endoscopic sinus surgery (FESS) were immunolabelled for B- and Z-DNA, as well as for both bacterial DNABII proteins. RESULTS Nineteen of 20 samples (95%) included areas rich in eDNA, with the majority in the Z-form. Areas positive for B-DNA were restricted to the most distal regions of the mucosal specimen. Labeling for both DNABII proteins was observed on B- and Z-DNA, which aligned with the role of these proteins in the B-to-Z DNA conversion. CONCLUSIONS Abundant Z-form eDNA in culture-positive pediatric CRS samples suggested that bacterial DNABII proteins were responsible for the conversion of eukaryotic B-DNA that had been released into the luminal space by PMNs during NETosis, to the Z-form. The presence of both DNABII proteins on B-DNA and Z-DNA supported the known role of these bacterial proteins in the B-to-Z DNA conversion. Given that Z-form DNA both stabilizes the bacterial biofilm and inactivates PMN NET-mediated killing of trapped bacteria, we hypothesize that this conversion may be contributing to the chronicity and recalcitrance of CRS to treatment. LEVEL OF EVIDENCE NA Laryngoscope, 134:1564-1571, 2024.
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Affiliation(s)
- Llwyatt K. Hofer
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children’s Hospital
| | - Joseph A. Jurcisek
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children’s Hospital
| | - Charles Elmaraghy
- The Ohio State University College of Medicine
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center
- Department of Pediatric Otolaryngology, Nationwide Children’s Hospital
| | - Steven D. Goodman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children’s Hospital
- The Ohio State University College of Medicine
| | - Lauren O. Bakaletz
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children’s Hospital
- The Ohio State University College of Medicine
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Böhning J, Tarafder AK, Bharat TA. The role of filamentous matrix molecules in shaping the architecture and emergent properties of bacterial biofilms. Biochem J 2024; 481:245-263. [PMID: 38358118 PMCID: PMC10903470 DOI: 10.1042/bcj20210301] [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: 09/18/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/16/2024]
Abstract
Numerous bacteria naturally occur within spatially organised, multicellular communities called biofilms. Moreover, most bacterial infections proceed with biofilm formation, posing major challenges to human health. Within biofilms, bacterial cells are embedded in a primarily self-produced extracellular matrix, which is a defining feature of all biofilms. The biofilm matrix is a complex, viscous mixture primarily composed of polymeric substances such as polysaccharides, filamentous protein fibres, and extracellular DNA. The structured arrangement of the matrix bestows bacteria with beneficial emergent properties that are not displayed by planktonic cells, conferring protection against physical and chemical stresses, including antibiotic treatment. However, a lack of multi-scale information at the molecular level has prevented a better understanding of this matrix and its properties. Here, we review recent progress on the molecular characterisation of filamentous biofilm matrix components and their three-dimensional spatial organisation within biofilms.
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Affiliation(s)
- Jan Böhning
- Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, U.K
| | - Abul K. Tarafder
- Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, U.K
| | - Tanmay A.M. Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, U.K
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Buzzo JR, Devaraj A, Gloag ES, Jurcisek JA, Robledo-Avila F, Kesler T, Wilbanks K, Mashburn-Warren L, Balu S, Wickham J, Novotny LA, Stoodley P, Bakaletz LO, Goodman SD. Z-form extracellular DNA is a structural component of the bacterial biofilm matrix. Cell 2021; 184:5740-5758.e17. [PMID: 34735796 DOI: 10.1016/j.cell.2021.10.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 08/03/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022]
Abstract
Biofilms are community architectures adopted by bacteria inclusive of a self-formed extracellular matrix that protects resident bacteria from diverse environmental stresses and, in many species, incorporates extracellular DNA (eDNA) and DNABII proteins for structural integrity throughout biofilm development. Here, we present evidence that this eDNA-based architecture relies on the rare Z-form. Z-form DNA accumulates as biofilms mature and, through stabilization by the DNABII proteins, confers structural integrity to the biofilm matrix. Indeed, substances known to drive B-DNA into Z-DNA promoted biofilm formation whereas those that drive Z-DNA into B-DNA disrupted extant biofilms. Importantly, we demonstrated that the universal bacterial DNABII family of proteins stabilizes both bacterial- and host-eDNA in the Z-form in situ. A model is proposed that incorporates the role of Z-DNA in biofilm pathogenesis, innate immune response, and immune evasion.
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Affiliation(s)
- John R Buzzo
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Aishwarya Devaraj
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Erin S Gloag
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA
| | - Joseph A Jurcisek
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Frank Robledo-Avila
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Theresa Kesler
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Kathryn Wilbanks
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Lauren Mashburn-Warren
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Sabarathnam Balu
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Joseph Wickham
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Laura A Novotny
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Paul Stoodley
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA; National Centre for Advanced Tribology at Southampton, University of Southampton, Southampton S017 1BJ, UK
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
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7
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Panlilio H, Rice CV. The role of extracellular DNA in the formation, architecture, stability, and treatment of bacterial biofilms. Biotechnol Bioeng 2021; 118:2129-2141. [PMID: 33748946 DOI: 10.1002/bit.27760] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/01/2020] [Accepted: 03/04/2021] [Indexed: 12/16/2022]
Abstract
Advances in biotechnology to treat and cure human disease have markedly improved human health and the development of modern societies. However, substantial challenges remain to overcome innate biological factors that thwart the activity and efficacy of pharmaceutical therapeutics. Until recently, the importance of extracellular DNA (eDNA) in biofilms was overlooked. New data reveal its extensive role in biofilm formation, adhesion, and structural integrity. Different approaches to target eDNA as anti-biofilm therapies have been proposed, but eDNA and the corresponding biofilm barriers are still difficult to disrupt. Therefore, more creative approaches to eradicate biofilms are needed. The production of eDNA often originates with the genetic material of bacterial cells through cell lysis. However, genomic DNA and eDNA are not necessarily structurally or compositionally identical. Variations are noteworthy because they dictate important interactions within the biofilm. Interactions between eDNA and biofilm components may as well be exploited as alternative anti-biofilm strategies. In this review, we discuss recent developments in eDNA research, emphasizing potential ways to disrupt biofilms. This review also highlights proteins, exopolysaccharides, and other molecules interacting with eDNA that can serve as anti-biofilm therapeutic targets. Overall, the array of diverse interactions with eDNA is important in biofilm structure, architecture, and stability.
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Affiliation(s)
- Hannah Panlilio
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Charles V Rice
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
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Basu HS, Sturkenboom MC, Delcros JG, Csokan PP, Szollosi J, Feuerstein BG, Marton LJ. Effect of polyamine depletion on chromatin structure in U-87 MG human brain tumour cells. Biochem J 1992; 282 ( Pt 3):723-7. [PMID: 1554353 PMCID: PMC1130847 DOI: 10.1042/bj2820723] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The chromatin structure of polyamine-depleted U-87 MG human brain tumour cells was studied by following the kinetics of digestion of cell nuclei by micrococcal nuclease and bovine pancreatic DNAase I. Cells growing in monolayers were treated with either alpha-difluoromethylornithine (DFMO), to deplete putrescine and spermidine, or N1,N14-bis(ethyl)homospermine (BE-4-4-4), to deplete putrescine, spermidine and spermine. BE-4-4-4 increased the initial rates of digestion and the magnitudes of limit digest by both enzymes; DFMO increased the limit digests without affecting initial digestion rates. Addition of 1 mM-putrescine 1 day after addition of DFMO reversed the effect of DFMO on limit digests. (Because polyamine uptake is low in cells treated with BE-4-4-4, and because putrescine does not reverse the growth-inhibitory effects of BE-4-4-4, reversal of the effects of BE-4-4-4 with putrescine was not attempted.) The increases in initial rates and limit digests did not result from changes in the lengths of nucleosomal or linker DNA, from blocks in cell-cycle progression, or from growth inhibition caused by DFMO or BE-4-4-4. Thus, because the limit digest is highest in cells with the lowest polyamine levels, it seems clear that the enhanced enzymic digestion of nuclei is caused by polyamine depletion and its possible effect on chromatin structure.
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Affiliation(s)
- H S Basu
- Department of Neurological Surgery, School of Medicine, University of California, San Francisco 94143
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Delic J, Onclercq R, Moisan-Coppey M. Inhibition and enhancement of eukaryotic gene expression by potential non-B DNA sequences. Biochem Biophys Res Commun 1991; 181:818-26. [PMID: 1755861 DOI: 10.1016/0006-291x(91)91263-c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In a transient or constitutive expression assay we have examined the effect of non-B DNA sequences d(CA)40 and d(CAAAAATGCC)n on gene expression in eukaryotic cells. These sequences were cloned adjacent to the weak eukaryotic promoter (CGTATTTATTTG) and located upstream from the coding sequence of galactokinase enzyme. Recombinants were micro-injected in cultured cells (Chinese hamster fibroblasts R1610, mutant gal-K-) and expression levels have been determined. The alternating purine-pyrimidine tract found in d(CA)40 able to assume the Z-DNA conformation shows an inhibitory effect on gene expression. In addition, our results suggest a new potential role of Z-DNA motifs in vivo to stimulate recombination. The sequences d(CAAAAATGCC)n able to adopt another non-B structure, corresponding to curved (or bended) helix conformation, strongly enhance gene expression and this enhancement depends on sequence redundancy.
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Affiliation(s)
- J Delic
- Institut Curie, Section de Biologie, INSERM U219, Paris, France
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10
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Delic J, Onclercq R, Moisan-Coppey M. Inhibition and enhancement of eukaryotic gene expression by potential non-B DNA sequences. Biochem Biophys Res Commun 1991; 180:1273-83. [PMID: 1953778 DOI: 10.1016/s0006-291x(05)81333-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In a transient or constitutive expression assay we have examined the effect of non-B DNA sequences d(CA)40 and d(CAAAAATGCC)n on gene expression in eukaryotic cells. These sequences were cloned adjacent to the weak eukaryotic promoter (CGTATTTATTTG) and located upstream from the coding sequence of galactokinase enzyme. Recombinants were micro-injected in cultured cells (Chinese hamster fibroblasts R1610, mutant gal-K-) and expression levels have been determined. The alternating purine-pyrimidine tract found in d(CA)40 able to assume the Z-DNA conformation shows an inhibitory effect on gene expression. In addition, our results suggest a new potential role of Z-DNA motifs in vivo to stimulate recombination. The sequences d(CAAAAATGCC)n able to adopt another non-B structure, corresponding to curved or bended helix conformation, strongly enhance gene expression and this enhancement depends on sequence redundancy.
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Affiliation(s)
- J Delic
- Institut Curie, INSERM U219, Paris, France
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11
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Veaute X, Fuchs RP. Polymorphism in N-2-acetylaminofluorene induced DNA structure as revealed by DNase I footprinting. Nucleic Acids Res 1991; 19:5603-6. [PMID: 1945836 PMCID: PMC328963 DOI: 10.1093/nar/19.20.5603] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In this paper, we have constructed double stranded helices (60-mers) containing a single N-2-acetylaminofluorene (-AAF) adduct covalently bound to one of the three guanine residues of the Narl site (G1G2CG3CC). This sequence was identified as a strong frameshift mutation hot spot for many carcinogens that bind to the C8 position of guanine. Using DNase I as a probe for DNA conformation we show i) that the average size of the helix deformation extends over 3 to 5 base pairs in both directions from the adduct site, and ii) that there is a strong polymorphism in the adduct induced DNA conformation. The present study supports the idea that adducts induce specific sequence dependent local conformational changes in DNA that are differentially recognized and processed by the enzymatic machineries that lead to repair or mutagenesis.
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Affiliation(s)
- X Veaute
- Institut de Biologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Strasbourg, France
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