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Published on: August 25, 2017
Cis-acting negative control of DNA replication in eukaryotic cells
1Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington 98104.
Cell
|February 12, 1988
Summary
Replication of a chimeric SV40-BPV episome occurs once per cell cycle, controlled by a cis-acting negative mechanism. This ensures stable episome maintenance by preventing re-replication within the same cell cycle.
Area of Science:
- Molecular Biology
- Epigenetics
- Virology
Background:
- Episomal replicons require precise cell cycle control to maintain stable copy numbers.
- Understanding the mechanisms governing DNA replication initiation and termination is crucial for genome stability.
Purpose of the Study:
- To investigate the cell cycle-dependent replication control of a chimeric simian virus 40-bovine papillomavirus (SV40-BPV) episomal replicon.
- To identify the regulatory mechanisms ensuring once-per-cell-cycle replication of episomal DNA.
Main Methods:
- Utilized stable monkey cell lines harboring a chimeric SV40-BPV episomal replicon.
- Analyzed replication frequency and episome copy number maintenance across cell cycles.
- Investigated the role of the T antigen initiation factor in replication control.
Main Results:
- The SV40-BPV episomal replicon replicated exactly once per cell cycle.
- Episome copy number remained stable, even with excess T antigen.
- A cis-acting negative control mechanism was identified, preventing re-replication of duplicated episomes.
Conclusions:
- Replication control of this episome is mediated by a novel cis-acting negative mechanism, not by limiting positive factors.
- The SV40 T antigen forms a stable, potentially heritable association with the episomal template post-replication.
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