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The DNA unwinding element binding protein DUE-B interacts with Cdc45 in preinitiation complex formation.
1Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA.
Molecular and Cellular Biology
|January 13, 2010
Summary
DNA replication initiation requires Cdc45 loading. This study reveals that DNA unwinding element-binding protein B (DUE-B) and Cdc45 interact and bind to active replication origins, facilitating initiation.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- DNA replication initiation is a complex process requiring precise regulation.
- The MCM helicase activator Cdc45 is crucial for loading at replication origins.
- The DNA unwinding element (DUE) plays a critical role in origin activation.
Purpose of the Study:
- To investigate the interaction between Cdc45 and DUE-binding proteins.
- To determine the role of DUE-B in replication origin activation and Cdc45 loading.
- To elucidate the mechanism of replication initiation at specific origins.
Main Methods:
- Co-immunoprecipitation to study protein interactions.
- Chromatin immunoprecipitation to assess protein localization.
- Xenopus egg extract replication assays.
- Analysis of replication origins with varying DUE sequences.
Main Results:
- Cdc45 interacts with the DUE-binding protein DUE-B.
- Both proteins localize to DUEs of active replication origins.
- Functional DUEs are essential for DUE-B and Cdc45 binding and origin activation.
- DUE-B, Cdc45, and TopBP1 form complexes, and DUE-B is required for Cdc45 and TopBP1 loading during replication.
Conclusions:
- DUE-B and Cdc45 binding to origins is coordinated and essential for replication initiation.
- Complex formation between DUE-B, Cdc45, and TopBP1 is critical for the initiation of DNA replication.
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