Related Experiment Videos
Modulation of DNMT1 activity by ADP-ribose polymers
Anna Reale1, Giovanna De Matteis, Giada Galleazzi
1Department of Cellular Biotechnologies and Haematology, University of Rome 'La Sapienza', 00161 Rome, Italy.
Oncogene
|January 8, 2005
Summary
Poly(ADP-ribose) polymerases (PARP) inhibition leads to DNA hypermethylation. We found that poly ADP-ribose directly binds and inhibits DNA methyltransferase 1 (DNMT1), suggesting a novel regulatory mechanism.
Area of Science:
- Molecular Biology
- Epigenetics
- Biochemistry
Background:
- Competitive inhibition of poly(ADP-ribose) polymerases (PARP) using 3-aminobenzamide in mammalian cells results in genome-wide DNA hypermethylation and anomalous CpG island hypermethylation.
- The precise molecular mechanisms linking poly(ADP-ribosyl)ation to DNA methylation remain elusive.
Purpose of the Study:
- To elucidate the molecular connection between poly(ADP-ribosyl)ation and DNA methylation.
- To investigate the interaction between PARP activity and DNA methyltransferase 1 (DNMT1).
Main Methods:
- In vitro binding assays to assess the interaction between DNMT1 and poly ADP-ribose polymers.
- Enzyme activity assays to measure DNMT1 activity upon binding with poly ADP-ribose.
- Co-immunoprecipitation experiments to determine the in vivo association of PARP1 and DNMT1.
Main Results:
- DNMT1 non-covalently binds to long and branched ADP-ribose polymers.
- Binding of poly ADP-ribose to DNMT1 inhibits its DNA methyltransferase activity.
- PARP1 and DNMT1 form a complex in vivo, where PARP1 is in its ADP-ribosylated isoform.
Conclusions:
- The interaction between poly ADP-ribose and DNMT1 provides a direct molecular link between PARP activity and DNA methylation.
- The PARP1-DNMT1 complex, with ADP-ribosylated PARP1, appears to be catalytically inefficient for DNA methylation, suggesting a regulatory role in epigenetic control.