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Updated: Jun 10, 2025
07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
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RNA Polymerase II is a Polar Roadblock to a Progressing DNA Fork
Taryn M Kay1, James T Inman2,3, Lucyna Lubkowska4
1Biophysics Program, Cornell University, Ithaca, NY 14853, USA.
Biorxiv : the Preprint Server for Biology
|October 17, 2024
Summary
Conflicts between DNA replication and transcription arise from RNA polymerase (Pol II) stalling. This study reveals Pol II has inherent polarity, forming stable roadblocks, especially with RNA-DNA hybrids, impacting genome stability.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- DNA replication and transcription frequently collide on the same DNA template.
- These conflicts can stall replication forks, posing risks to genome stability.
- The inherent polarity of RNA polymerase (Pol II) roadblocks remains poorly understood.
Purpose of the Study:
- To investigate the inherent polarity of Pol II roadblocks during transcription-replication conflicts.
- To elucidate the structural basis and impact of RNA-DNA hybrids in these conflicts.
- To understand the role of TFIIS in resolving these roadblocks.
Main Methods:
- Utilized a simplified model system with mechanical DNA unzipping to mimic replisome progression.
- Examined Pol II roadblock stability in head-on and co-directional configurations.
- Analyzed the formation and role of RNA-DNA hybrids and TFIIS activity.
Main Results:
- Pol II exhibits inherent polarity, forming more stable roadblocks in head-on collisions.
- Elongating Pol II with longer transcripts creates more persistent roadblocks, enhanced by RNA-DNA hybrids.
- Backtracked Pol II can form topological locks via lagging strand RNA-DNA hybrids, which TFIIS can resolve.
Conclusions:
- Pol II roadblocks possess inherent polarity, exacerbated by RNA-DNA hybrid formation.
- RNA-DNA hybrids play a critical role in stabilizing Pol II roadblocks and can even prime DNA replication.
- TFIIS facilitates the resolution of these conflicts by removing RNA-DNA hybrids.
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