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The DNA unwinding element binding protein DUE-B interacts with Cdc45 in preinitiation complex formation

A Chowdhury1, G Liu, M Kemp

  • 1Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA.

Molecular and Cellular Biology
|January 13, 2010
PubMed

Insights

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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