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Imre L, Niaki EF, Bosire R, Nanasi P, Nagy P, Bacso Z, Hamidova N, Pommier Y, Jordan A, Szabo G. Nucleosome destabilization by polyamines. Arch Biochem Biophys 2022; 722:109184. [PMID: 35395253 PMCID: PMC10572104 DOI: 10.1016/j.abb.2022.109184] [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: 12/29/2021] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 11/19/2022]
Abstract
The roles and molecular interactions of polyamines (PAs) in the nucleus are not fully understood. Here their effect on nucleosome stability, a key regulatory factor in eukaryotic gene control, is reported, as measured in agarose embedded nuclei of H2B-GFP expressor HeLa cells. Nucleosome stability was assessed by quantitative microscopy [1,2] in situ, in close to native state of chromatin, preserving the nucleosome constrained topology of the genomic DNA. A robust destabilizing effect was observed in the millimolar concentration range in the case of spermine, spermidine as well as putrescine, which was strongly pH and salt concentration-dependent, and remained significant also at neutral pH. The integrity of genomic DNA was not affected by PA treatment, excluding DNA break-elicited topological relaxation as a factor in destabilization. The binding of PAs to DNA was demonstrated by the displacement of ethidium bromide, both from deproteinized nuclear halos and from plasmid DNA. The possibility that DNA methylation patterns may be influenced by PA levels is contemplated in the context of gene expression and DNA methylation correlations identified in the NCI-60 panel-based CellMiner database: methylated loci in subsets of high-ODC1 cell lines and the dependence of PER3 DNA methylation on PA metabolism.
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Affiliation(s)
- Laszlo Imre
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Erfaneh Firouzi Niaki
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Rosevalentine Bosire
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Peter Nanasi
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Peter Nagy
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Zsolt Bacso
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Nubar Hamidova
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary
| | - Yves Pommier
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892-4255, USA
| | - Albert Jordan
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, 08028, Spain
| | - Gabor Szabo
- Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine Debrecen, H-4032, Hungary.
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Imre L, Balogh I, Kappelmayer J, Szabó M, Melegh B, Wanker E, Szabó G. Detection of mutations by flow cytometric melting point analysis of PCR products. Cytometry A 2011; 79:720-6. [PMID: 21774077 DOI: 10.1002/cyto.a.21104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 11/09/2022]
Abstract
Exploring the possibilities offered by flow cytometric microbead analyses for the detection of genetic alterations, an assay based on the dependence of the melting point of double-stranded DNA molecules on their length has been developed, making use of PCR products carrying biotin and fluorescent moiety on their two ends. The samples of different length PCR products immobilized on streptavidine coated microbeads are heat-treated in the presence of formamide at temperatures between the melting point of the longer and that of the shorter PCR product, when the mean fluorescence intensity of the beads carrying the shorter molecules decreases as a result of denaturation, as opposed to the sample containing the longer product. The efficacy and sensitivity of the method is demonstrated in the case of the assessment of the degree of triplet expansion in Huntington's disease. Its utility for the detection of point mutations in heterozygous clinical samples is shown in the case of the BRCA1 gene. The assay is simple and may be offered for the purposes of clinical diagnostics of a number of genetic conditions. These include screening of samples for triplet expansions and SNPs predisposing for particular pathological or pharmacogenomic conditions. In general, the method described herein is offered for the diagnosis of any pathological condition where the length of a genomic or cDNA sequence is expected to be different from that of the normal allele.
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Affiliation(s)
- László Imre
- Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, Hungary
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