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Wang RH, Lahusen TJ, Chen Q, Xu X, Jenkins LMM, Leo E, Fu H, Aladjem M, Pommier Y, Appella E, Deng CX. SIRT1 deacetylates TopBP1 and modulates intra-S-phase checkpoint and DNA replication origin firing. Int J Biol Sci 2014; 10:1193-202. [PMID: 25516717 PMCID: PMC4261203 DOI: 10.7150/ijbs.11066] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 11/24/2014] [Indexed: 12/22/2022] Open
Abstract
SIRT1, the mammalian homolog of yeast Sir2, is a founding member of a family of 7 protein and histone deacetylases that are involved in numerous biological functions. Previous studies revealed that SIRT1 deficiency results in genome instability, which eventually leads to cancer formation, yet the underlying mechanism is unclear. To investigate this, we conducted a proteomics study and found that SIRT1 interacted with many proteins involved in replication fork protection and origin firing. We demonstrated that loss of SIRT1 resulted in increased replication origin firing, asymmetric fork progression, defective intra-S-phase checkpoint, and chromosome damage. Mechanistically, SIRT1 deacetylates and affects the activity of TopBP1, which plays an essential role in DNA replication fork protection and replication origin firing. Our study demonstrated that ectopic over-expression of the deacetylated form of TopBP1 in SIRT1 mutant cells repressed replication origin firing, while the acetylated form of TopBP1 lost this function. Thus, SIRT1 acts upstream of TopBP1 and plays an essential role in maintaining genome stability by modulating DNA replication fork initiation and the intra-S-phase cell cycle checkpoint.
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Affiliation(s)
- Rui-Hong Wang
- 1. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland MD 20892, USA; ; 4. Faculty of Health Sciences, University of Macau, Macau, SAR of People's Republic of China
| | - Tyler J Lahusen
- 1. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Qiang Chen
- 1. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Xiaoling Xu
- 1. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland MD 20892, USA; ; 4. Faculty of Health Sciences, University of Macau, Macau, SAR of People's Republic of China
| | - Lisa M Miller Jenkins
- 2. Laboratory of Cell Biology, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Elisabetta Leo
- 3. Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Haiqing Fu
- 3. Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Mirit Aladjem
- 3. Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Yves Pommier
- 3. Developmental Therapeutics Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Ettore Appella
- 2. Laboratory of Cell Biology, National Institutes of Health, Bethesda, Maryland MD 20892, USA
| | - Chu-Xia Deng
- 1. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland MD 20892, USA; ; 4. Faculty of Health Sciences, University of Macau, Macau, SAR of People's Republic of China
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