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Identification of a protein from Saccharomyces cerevisiae with E2F-like DNA-binding and transactivating properties
Abstract:
The promoter of the human proto-oncogene MYC has been the first cellular target shown to be subject to regulation by the E2F transcription factor. E2F also has binding sites in other promoters regulated by cell proliferation and during the cell cycle. We have analyzed Saccharomyces cerevisiae for the presence of an E2F-analogous protein. GAL1-based promoter constructs carrying the E2F binding site of the MYC or the adenovirus E2 promoter showed transcriptional activity in yeast cells. A DNA-binding factor, designated YE2F, binds specifically to the E2F consensus sequence and was partially purified from yeast extracts. YE2F showed identical contact points within the MYC binding site as authentic E2F protein from mammalian cells. The results suggest that the existence of an E2F-like protein in the yeast S. cerevisiae.
Insights
Researchers identified a yeast protein, YE2F, that functions similarly to the E2F transcription factor found in mammals. This discovery suggests conserved regulatory mechanisms controlling cell growth and division across species.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Transcription Factor Research
Background:
- The E2F transcription factor regulates genes involved in cell proliferation and the cell cycle.
- The MYC proto-oncogene promoter was the first identified E2F target in human cells.
- E2F binding sites are present in promoters crucial for cell cycle progression.
Purpose of the Study:
- To investigate the presence of an E2F-analogous protein in Saccharomyces cerevisiae (yeast).
- To determine if yeast possesses transcription factors with similar functions to mammalian E2F.
- To explore potential evolutionary conservation of E2F-mediated gene regulation.
Main Methods:
- Utilized GAL1-based promoter constructs containing known E2F binding sites (from MYC and adenovirus E2 promoters).
- Assessed transcriptional activity of these constructs in yeast cells.
- Performed partial purification of a DNA-binding factor from yeast extracts.
- Characterized the DNA-binding specificity and target site interactions of the purified factor.
Main Results:
- Yeast cells exhibited transcriptional activity from promoters containing E2F binding sites.
- A specific DNA-binding factor, named YE2F, was identified in yeast.
- YE2F demonstrated specific binding to the E2F consensus sequence.
- YE2F shared identical contact points within the MYC binding site as mammalian E2F.
Conclusions:
- The findings strongly suggest the existence of an E2F-like protein in Saccharomyces cerevisiae.
- This indicates a potential evolutionary conservation of E2F-related transcription factors and their regulatory functions.
- YE2F represents a yeast homolog of the E2F family, offering a model for studying cell cycle control mechanisms.