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Human topoisomerase IIalpha and IIbeta interact with the C-terminal region of p53
I G Cowell1, A L Okorokov, S A Cutts
1School of Biochemistry and Genetics, University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom.
Abstract:
The p53 tumor suppressor protein is a critical regulator of cell cycle progression and apoptosis following exposure of cells to DNA damaging agents such as ionizing radiation or anticancer drugs. An important group of anticancer drugs, including compounds such as etoposide and doxorubicin (Adriamycin), interacts with DNA topoisomerase II (topo II), causing the accumulation of enzyme-DNA adducts that ultimately lead to double-strand breaks and cell death via apoptosis. Human topo IIbeta has previously been shown to interact with p53, and we have extended this analysis to show that both topo IIalpha and IIbeta interact with p53 in vivo and in vitro. Furthermore, we show that the regulatory C-terminal basic region of p53 (residues 364-393) is necessary and sufficient for interaction with DNA topo II.
Insights
The p53 protein interacts with DNA topoisomerase II (topo II) alpha and beta in cells and in vitro. This interaction, crucial for cancer drug efficacy, is mediated by p53
Area of Science:
- Molecular Biology
- Cancer Research
- Biochemistry
Background:
- The p53 protein is a key regulator of cell cycle arrest and apoptosis in response to DNA damage.
- Certain anticancer drugs, like etoposide and doxorubicin, function by inhibiting DNA topoisomerase II (topo II), leading to DNA breaks and cell death.
- Previous studies indicated an interaction between p53 and human topo IIbeta.
Purpose of the Study:
- To investigate the interaction between p53 and both human topo IIalpha and topo IIbeta.
- To determine the specific region of p53 involved in binding to DNA topo II.
Main Methods:
- In vivo and in vitro assays were employed to study protein-protein interactions.
- Analysis focused on the interaction between p53 and DNA topoisomerase IIalpha and IIbeta.
Main Results:
- Both topo IIalpha and topo IIbeta were shown to interact with p53.
- The interaction was confirmed to occur both in vivo and in vitro.
- The C-terminal basic region of p53 (residues 364-393) was identified as essential and sufficient for binding to DNA topo II.
Conclusions:
- p53 interacts with both isoforms of human DNA topoisomerase II.
- The C-terminal region of p53 plays a critical role in mediating this interaction.
- Understanding this interaction may provide insights into the mechanisms of action for topo II-targeting anticancer drugs.