Related Experiment Video
Updated: Jun 10, 2026
09:07
Live-Cell Imaging of Transcriptional Activity at DNA Double-Strand Breaks
Published on: September 20, 2021
Deciphering the chromatin landscape induced around DNA double strand breaks
Laurent Massip1, Pierre Caron, Jason S Iacovoni
1LBCMCP, CNRS and University of Toulouse, France.
Cell Cycle (Georgetown, Tex.)
|August 18, 2010
Summary
Researchers developed a novel system to precisely induce DNA double-strand breaks (DSBs) and map associated chromatin changes. This breakthrough enables detailed study of DNA repair mechanisms and chromatin modifications at DSB sites.
Area of Science:
- Molecular Biology
- Genomics
- Biochemistry
Background:
- DNA double-strand breaks (DSBs) are critical DNA lesions requiring efficient repair.
- Understanding chromatin alterations around DSBs is essential for molecular biologists.
- Existing methods for studying DSB-induced chromatin changes were limited by induction techniques.
Purpose of the Study:
- To present a novel experimental system for generating specific DNA double-strand breaks (DSBs).
- To enable high-resolution profiling of chromatin modifications and DNA repair complexes at DSB sites.
- To investigate the genome-wide distribution and properties of the gammaH2AX modification post-DSB induction.
Main Methods:
- Development of a AsiSI-ER system for inducible, sequence-specific DSB generation.
- Utilizing 4-hydroxytamoxifen (4OHT) to activate the AsiSI-ER construct.
- Employing Chromatin Immunoprecipitation sequencing (ChIP-seq) to map protein-genome interactions and chromatin modifications.
Main Results:
- Generation of cell lines with precisely positioned, inducible DSBs across the genome.
- Production of the first genome-wide map of gammaH2AX, a key DSB marker, using ChIP-seq.
- Characterization of the spreading properties of gammaH2AX in response to DSBs.
Conclusions:
- The AsiSI-ER system provides a powerful tool for studying DSB repair dynamics.
- This system facilitates high-resolution analysis of chromatin changes at DSB sites.
- The developed methodology opens new avenues for investigating previously uncharacterized aspects of DNA double-strand break repair.
More Related Videos
Related Concept Videos
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
02:05Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
02:25Spreading of Chromatin Modifications
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer is an enzyme that can...
Writers
The writer is an enzyme that can...