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Banerjee A, Majumder P, Sanyal S, Singh J, Jana K, Das C, Dasgupta D. The DNA intercalators ethidium bromide and propidium iodide also bind to core histones. FEBS Open Bio 2014; 4:251-9. [PMID: 24649406 PMCID: PMC3958746 DOI: 10.1016/j.fob.2014.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 01/17/2023] Open
Abstract
Eukaryotic DNA is compacted in the form of chromatin, in a complex with histones and other non-histone proteins. The intimate association of DNA and histones in chromatin raises the possibility that DNA-interactive small molecules may bind to chromatin-associated proteins such as histones. Employing biophysical and biochemical techniques we have characterized the interaction of a classical intercalator, ethidium bromide (EB) and its structural analogue propidium iodide (PI) with hierarchical genomic components: long chromatin, chromatosome, core octamer and chromosomal DNA. Our studies show that EB and PI affect both chromatin structure and function, inducing chromatin compaction and disruption of the integrity of the chromatosome. Calorimetric studies and fluorescence measurements of the ligands demonstrated and characterized the association of these ligands with core histones and the intact octamer in absence of DNA. The ligands affect acetylation of histone H3 at lysine 9 and acetylation of histone H4 at lysine 5 and lysine 8 ex vivo. PI alters the post-translational modifications to a greater extent than EB. This is the first report showing the dual binding (chromosomal DNA and core histones) property of a classical intercalator, EB, and its longer analogue, PI, in the context of chromatin.
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Affiliation(s)
- Amrita Banerjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Parijat Majumder
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Sulagna Sanyal
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Jasdeep Singh
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Kuladip Jana
- Division of Molecular Medicine, Centre for Translational Animal Research, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, West Bengal, India
| | - Chandrima Das
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Dipak Dasgupta
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
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Bonaly J, Bre MH, Lefort-Tran M, Mestre JC. A flow cytometric study of DNA staining in situ in exponentially growing and stationary Euglena gracilis. CYTOMETRY 1987; 8:42-5. [PMID: 2433111 DOI: 10.1002/cyto.990080107] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
DNA stainability by different fluorochromes has been compared in exponentially dividing and stationary Euglena cells. With the intercalating fluorochromes, ethidium bromide, acridine orange and DAPI, a decrease of fluorescence intensity of the G1 cells is observed when cells enter stationary stage. However this decrease of fluorescence is not obtained with the nonintercalating fluorochrome Hoechst 33258. If nuclear basic proteins are extracted, however, the intensity of staining by either Hoechst 33258 or ethidium-bromide is comparable in stationary and dividing cells. Therefore, the decrease of fluorescence intensity of the G1 cells observed during the transition from exponential to stationary phase is not due to a loss of DNA but is related to the exposure of chromatin binding sites for ethidium bromide. In Euglena cells, DNA accessibility for intercalating fluorochromes depends upon chromatin structure and consequently upon cell age.
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