Related Experiment Video
Updated: Feb 4, 2026
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DamID-seq: Genome-wide Mapping of Protein-DNA Interactions by High Throughput Sequencing of Adenine-methylated DNA Fragments
Published on: January 27, 2016
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POTENTIATION EFFECTS OF 3-AMINOBENZAMIDE ON DIVALENT CATION-DEPENDENT DNA FRAGMENTATION IN MAMMALIAN CELLS EXPOSED TO
1DEPARTMENT OF MOLECULAR BIOLOGY, WONKWANG UNIVERSITY, IRI, REPUBLIC OF KOREA.
In Vitro Toxicology
|September 28, 2018
Summary
Methyl methanesulfonate (MMS) causes DNA fragmentation dependent on calcium and magnesium ions. Inhibiting poly (ADP-ribose) polymerase with 3-aminobenzamide activates an endonuclease, enhancing DNA cutting.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Methyl methanesulfonate (MMS) is a known DNA-damaging agent.
- Cells possess repair mechanisms to counteract DNA damage.
- Nuclease activity plays a crucial role in DNA repair pathways.
Purpose of the Study:
- To investigate the properties of nuclease activity related to methyl methanesulfonate (MMS) DNA damage.
- To elucidate the role of divalent cations (Ca++ and Mg++) in MMS-induced DNA fragmentation.
- To examine the effect of 3-aminobenzamide (3-AB) on MMS damage-related nuclease activity.
Main Methods:
- Neutral and alkaline elution techniques were employed to study DNA fragmentation.
- Agarose gel electrophoresis and densitometric analysis were used to assess DNA modifications.
- Nuclear extracts from CHO cells were utilized to study enzyme activity.
Main Results:
- MMS-induced DNA fragmentation was dependent on the presence of Ca++ and Mg++ ions.
- Divalent ion chelators like EDTA and EGTA inhibited MMS-induced DNA fragmentation.
- 3-Aminobenzamide (3-AB) treatment significantly increased Ca++ and Mg++-dependent conversion of supercoiled plasmid DNA to open circular form.
Conclusions:
- The study suggests that inhibition of poly (ADP-ribose) polymerase by 3-AB activates a Ca++, Mg++-dependent endonuclease.
- This activated endonuclease non-specifically cleaves MMS-treated DNA.
- Divalent cations are critical for the nuclease activity involved in processing MMS-induced DNA damage.
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