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E2F integrates cell cycle progression with DNA repair, replication, and G(2)/M checkpoints
Bing Ren1, Hieu Cam, Yasuhiko Takahashi
1Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
Abstract:
The E2F transcription factor family is known to play a key role in the timely expression of genes required for cell cycle progression and proliferation, but only a few E2F target genes have been identified. We explored the possibility that E2F regulators play a broader role by identifying additional genes bound by E2F in living human cells. A protocol was developed to identify genomic binding sites for DNA-binding factors in mammalian cells that combines immunoprecipitation of cross-linked protein-DNA complexes with DNA microarray analysis. Among approximately 1200 genes expressed during cell cycle entry, we found that the promoters of 127 were bound by the E2F4 transcription factor in primary fibroblasts. A subset of these targets was also bound by E2F1. Most previously identified target genes known to have roles in DNA replication and cell cycle control and represented on the microarray were confirmed by this analysis. We also identified a remarkable cadre of genes with no previous connection to E2F regulation, including genes that encode components of the DNA damage checkpoint and repair pathways, as well as factors involved in chromatin assembly/condensation, chromosome segregation, and the mitotic spindle checkpoint. Our data indicate that E2F directly links cell cycle progression with the coordinate regulation of genes essential for both the synthesis of DNA as well as its surveillance.
Insights
Researchers identified new E2F transcription factor targets, revealing its role in DNA damage response and repair pathways beyond cell cycle progression. This expands our understanding of E2F
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- The E2F transcription factor family regulates genes crucial for cell cycle progression and proliferation.
- However, the full spectrum of E2F target genes remains largely uncharacterized.
Purpose of the Study:
- To identify novel E2F-bound genes in human cells, expanding the known regulatory network of E2F.
- To investigate the broader role of E2F transcription factors in cellular processes.
Main Methods:
- Developed a protocol combining immunoprecipitation of cross-linked protein-DNA complexes with DNA microarray analysis to identify genomic binding sites.
- Analyzed gene expression during cell cycle entry in primary human fibroblasts.
Main Results:
- Identified 127 promoter regions bound by E2F4 among approximately 1200 genes expressed during cell cycle entry.
- Confirmed known E2F targets involved in DNA replication and cell cycle control.
- Discovered new E2F targets in DNA damage checkpoint and repair pathways, chromatin assembly, chromosome segregation, and mitotic spindle checkpoint.
Conclusions:
- E2F transcription factors directly regulate a wider range of genes than previously known, including those involved in DNA surveillance.
- E2F links cell cycle progression with the coordinated regulation of DNA synthesis and DNA damage response pathways.