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Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
Ribosomal DNA replication fork barrier and HOT1 recombination hot spot: shared sequences but independent activities
T R Ward1, M L Hoang, R Prusty
1Department of Genetics, University of Washington, Seattle 98195, USA.
Molecular and Cellular Biology
|June 10, 2000
Summary
Replication fork barrier (RFB) and HOT1 recombination sites in yeast share some DNA sequences but HOT1 activity does not require fork arrest. This suggests a common trans-acting factor influences both processes.
Area of Science:
- Molecular Biology
- Genetics
- Yeast Biology
Background:
- The ribosomal DNA (rDNA) in Saccharomyces cerevisiae contains regulatory elements.
- Sequences in the nontranscribed spacer 3' of the 35S ribosomal RNA gene influence replication fork progression and recombination.
Purpose of the Study:
- To investigate the relationship between the replication fork barrier (RFB) and the HOT1 recombination site.
- To determine if RFB-mediated fork arrest is necessary for HOT1 activity.
Main Methods:
- Site-directed mutagenesis of rDNA sequences.
- Analysis of replication fork arrest at RFB sites.
- Measurement of mitotic recombination rates at the HOT1 locus.
Main Results:
- RFB and HOT1 activities share some essential sequences.
- Mutations affecting HOT1 recombination also impact RFB activity.
- HOT1-stimulated recombination occurs independently of replication fork arrest at RFB.
Conclusions:
- HOT1 and RFB functions are partially separable but share common sequence requirements.
- Replication fork arrest at RFB is not essential for HOT1-mediated recombination.
- A common trans-acting factor likely interacts with both RFB and HOT1 regulatory sequences.
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