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Oneto M, Scipioni L, Sarmento MJ, Cainero I, Pelicci S, Furia L, Pelicci PG, Dellino GI, Bianchini P, Faretta M, Gratton E, Diaspro A, Lanzanò L. Nanoscale Distribution of Nuclear Sites by Super-Resolved Image Cross-Correlation Spectroscopy. Biophys J 2019; 117:2054-2065. [PMID: 31732142 PMCID: PMC6895719 DOI: 10.1016/j.bpj.2019.10.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/21/2019] [Accepted: 10/29/2019] [Indexed: 02/07/2023] Open
Abstract
Deciphering the spatiotemporal coordination between nuclear functions is important to understand its role in the maintenance of human genome. In this context, super-resolution microscopy has gained considerable interest because it can be used to probe the spatial organization of functional sites in intact single-cell nuclei in the 20-250 nm range. Among the methods that quantify colocalization from multicolor images, image cross-correlation spectroscopy (ICCS) offers several advantages, namely it does not require a presegmentation of the image into objects and can be used to detect dynamic interactions. However, the combination of ICCS with super-resolution microscopy has not been explored yet. Here, we combine dual-color stimulated emission depletion (STED) nanoscopy with ICCS (STED-ICCS) to quantify the nanoscale distribution of functional nuclear sites. We show that super-resolved ICCS provides not only a value of the colocalized fraction but also the characteristic distances associated to correlated nuclear sites. As a validation, we quantify the nanoscale spatial distribution of three different pairs of functional nuclear sites in MCF10A cells. As expected, transcription foci and a transcriptionally repressive histone marker (H3K9me3) are not correlated. Conversely, nascent DNA replication foci and the proliferating cell nuclear antigen(PCNA) protein have a high level of proximity and are correlated at a nanometer distance scale that is close to the limit of our experimental approach. Finally, transcription foci are found at a distance of 130 nm from replication foci, indicating a spatial segregation at the nanoscale. Overall, our data demonstrate that STED-ICCS can be a powerful tool for the analysis of the nanoscale distribution of functional sites in the nucleus.
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Affiliation(s)
- Michele Oneto
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Lorenzo Scipioni
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Maria J Sarmento
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Isotta Cainero
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy; Department of Physics, University of Genoa, Genoa, Italy
| | - Simone Pelicci
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy; Department of Physics, University of Genoa, Genoa, Italy
| | - Laura Furia
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Pier G Pelicci
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Gaetano I Dellino
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Paolo Bianchini
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Mario Faretta
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Alberto Diaspro
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy; Department of Physics, University of Genoa, Genoa, Italy.
| | - Luca Lanzanò
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy.
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Bouwman BAM, Crosetto N. Endogenous DNA Double-Strand Breaks during DNA Transactions: Emerging Insights and Methods for Genome-Wide Profiling. Genes (Basel) 2018; 9:E632. [PMID: 30558210 PMCID: PMC6316733 DOI: 10.3390/genes9120632] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) jeopardize genome integrity and can-when repaired unfaithfully-give rise to structural rearrangements associated with cancer. Exogenous agents such as ionizing radiation or chemotherapy can invoke DSBs, but a vast amount of breakage arises during vital endogenous DNA transactions, such as replication and transcription. Additionally, chromatin looping involved in 3D genome organization and gene regulation is increasingly recognized as a possible contributor to DSB events. In this review, we first discuss insights into the mechanisms of endogenous DSB formation, showcasing the trade-off between essential DNA transactions and the intrinsic challenges that these processes impose on genomic integrity. In the second part, we highlight emerging methods for genome-wide profiling of DSBs, and discuss future directions of research that will help advance our understanding of genome-wide DSB formation and repair.
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Affiliation(s)
- Britta A M Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
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Sarmento MJ, Oneto M, Pelicci S, Pesce L, Scipioni L, Faretta M, Furia L, Dellino GI, Pelicci PG, Bianchini P, Diaspro A, Lanzanò L. Exploiting the tunability of stimulated emission depletion microscopy for super-resolution imaging of nuclear structures. Nat Commun 2018; 9:3415. [PMID: 30143630 PMCID: PMC6109149 DOI: 10.1038/s41467-018-05963-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 07/27/2018] [Indexed: 11/23/2022] Open
Abstract
Imaging of nuclear structures within intact eukaryotic nuclei is imperative to understand the effect of chromatin folding on genome function. Recent developments of super-resolution fluorescence microscopy techniques combine high specificity, sensitivity, and less-invasive sample preparation procedures with the sub-diffraction spatial resolution required to image chromatin at the nanoscale. Here, we present a method to enhance the spatial resolution of a stimulated-emission depletion (STED) microscope based only on the modulation of the STED intensity during the acquisition of a STED image. This modulation induces spatially encoded variations of the fluorescence emission that can be visualized in the phasor plot and used to improve and quantify the effective spatial resolution of the STED image. We show that the method can be used to remove direct excitation by the STED beam and perform dual color imaging. We apply this method to the visualization of transcription and replication foci within intact nuclei of eukaryotic cells.
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Affiliation(s)
- Maria J Sarmento
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the A.S.C.R. v.v.i., Prague, Czech Republic
| | - Michele Oneto
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Simone Pelicci
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
- Department of Physics, University of Genoa, via Dodecaneso 33, 16146, Genoa, Italy
| | - Luca Pesce
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
- Department of Physics, University of Genoa, via Dodecaneso 33, 16146, Genoa, Italy
| | - Lorenzo Scipioni
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Mario Faretta
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Laura Furia
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Gaetano Ivan Dellino
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20142, Milan, Italy
| | - Pier Giuseppe Pelicci
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20142, Milan, Italy
| | - Paolo Bianchini
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Alberto Diaspro
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.
- Department of Physics, University of Genoa, via Dodecaneso 33, 16146, Genoa, Italy.
| | - Luca Lanzanò
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.
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Stevanoni M, Palumbo E, Russo A. The Replication of Frataxin Gene Is Assured by Activation of Dormant Origins in the Presence of a GAA-Repeat Expansion. PLoS Genet 2016; 12:e1006201. [PMID: 27447727 PMCID: PMC4957762 DOI: 10.1371/journal.pgen.1006201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 06/27/2016] [Indexed: 12/17/2022] Open
Abstract
It is well known that DNA replication affects the stability of several trinucleotide repeats, but whether replication profiles of human loci carrying an expanded repeat differ from those of normal alleles is poorly understood in the endogenous context. We investigated this issue using cell lines from Friedreich's ataxia patients, homozygous for a GAA-repeat expansion in intron 1 of the Frataxin gene. By interphase, FISH we found that in comparison to the normal Frataxin sequence the replication of expanded alleles is slowed or delayed. According to molecular combing, origins never fired within the normal Frataxin allele. In contrast, in mutant alleles dormant origins are recruited within the gene, causing a switch of the prevalent fork direction through the expanded repeat. Furthermore, a global modification of the replication profile, involving origin choice and a differential distribution of unidirectional forks, was observed in the surrounding 850 kb region. These data provide a wide-view of the interplay of events occurring during replication of genes carrying an expanded repeat.
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Affiliation(s)
| | - Elisa Palumbo
- Department of Biology, University of Padova, Padova, Italy
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