Related Experiment Video
Updated: Jul 20, 2026
10:44
Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage
Published on: January 31, 2018
Five repair pathways in one context: chromatin modification during DNA repair
Yeganeh Ataian1, Jocelyn E Krebs
1Department of Biological Sciences, University of AK Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA.
Biochemistry and Cell Biology = Biochimie Et Biologie Cellulaire
|August 29, 2006
Summary
Cells use five major DNA repair pathways to fix daily DNA damage. Chromatin structure poses a challenge, but chromatin remodelers and histone modifiers help repair factors access damaged DNA.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Eukaryotic cells encounter over 10,000 DNA lesions daily.
- Failure to repair DNA damage can cause mutations, genomic instability, and cell death.
- Five major DNA repair pathways exist: homologous recombination, nonhomologous end joining, nucleotide excision repair, base excision repair, and mismatch repair.
Purpose of the Study:
- To review recent studies on the interplay between chromatin modifiers/remodelers and DNA repair pathways.
- To elucidate how cells overcome chromatin's barrier to DNA repair.
Main Methods:
- Review of recent scientific literature.
- Analysis of studies focusing on chromatin remodeling and DNA repair mechanisms.
Main Results:
- DNA is packaged into chromatin, a structure that impedes DNA repair.
- ATP-dependent chromatin-remodeling enzymes and histone-modifying enzymes facilitate access to damaged DNA sites.
- These enzymes are crucial for the efficient functioning of major DNA repair pathways within the chromatin context.
Conclusions:
- Chromatin accessibility is a critical factor in DNA repair efficiency.
- Chromatin modifiers and remodelers play essential roles in enabling DNA repair pathways to function.
- Understanding this interplay is key to comprehending genome stability maintenance.
Related Concept Videos
02:25Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
02:25Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
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...
02:04Fixing 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...
01:38Nucleotide Excision Repair
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...