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DNMT1 forms a complex with Rb, E2F1 and HDAC1 and represses transcription from E2F-responsive promoters
K D Robertson1, S Ait-Si-Ali, T Yokochi
1Laboratory of Molecular Embryology, NICHD, NIH, Bethesda, Maryland, USA.
Nature Genetics
|July 11, 2000
Summary
DNA methylation patterns are established by linking DNA methyltransferase (DNMT1) with sequence-specific DNA binding proteins. This process is crucial for regulating gene transcription and is disrupted in cancer.
Area of Science:
- Epigenetics
- Molecular Biology
- Cancer Biology
Background:
- DNA methylation of CpG islands correlates with gene silencing and formation of nuclease-resistant chromatin.
- Methyl-CpG-binding proteins link methylated DNA to hypoacetylated histones via histone deacetylase recruitment.
- Mechanisms establishing DNA methylation patterns and whether they are targeted by silent chromatin remain unclear.
Purpose of the Study:
- To investigate the mechanisms underlying DNA methylation pattern establishment.
- To explore the link between DNA methylation, histone deacetylases, and sequence-specific DNA binding.
- To understand the role of these interactions in growth regulation and cancer.
Main Methods:
- Co-purification of DNA methyltransferase DNMT1 with retinoblastoma (Rb) tumor suppressor and E2F1.
- Assessing the interaction between DNMT1, Rb, and HDAC1.
- Analyzing the repression of transcription from promoters with E2F-binding sites.
Main Results:
- DNMT1 co-purifies with Rb and E2F1.
- DNMT1 cooperates with Rb to repress transcription from E2F-binding site-containing promoters.
- Establishes a link between DNA methylation, histone deacetylase, and sequence-specific DNA binding.
Conclusions:
- Identifies a novel mechanism for DNA methylation pattern establishment involving sequence-specific DNA binding proteins.
- Highlights the role of DNMT1 and Rb in transcriptional repression.
- Reveals a disrupted growth-regulatory pathway in nearly all cancer cells, involving DNA methylation and histone deacetylases.