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Identification and characterization of a novel component of the human minichromosome maintenance complex

Amos M Sakwe1, Tin Nguyen, Vicki Athanasopoulos

  • 1Department of Medical Genetics, University of Toronto, Kings College Circle, Toronto, Ontario, Canada.

Molecular and Cellular Biology
|February 14, 2007
PubMed

Insights

Researchers discovered a new protein, MCM binding protein (MCM-BP), that forms stable DNA replication complexes in human cells, potentially replacing a known component and influencing chromatin binding.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • The Minichromosome maintenance (MCM) complex is crucial for DNA replication in eukaryotes.
  • Understanding the composition and regulation of MCM complexes is vital for comprehending genome stability.

Purpose of the Study:

  • To identify novel components of the MCM complex in human cells.
  • To characterize the function and properties of a newly discovered MCM-associated protein, MCM binding protein (MCM-BP).

Main Methods:

  • Tandem affinity purification-tagging in human cells.
  • Co-immunoprecipitation assays.
  • In vitro helicase activity assays.
  • Chromatin association studies using cell cycle analysis.

Main Results:

  • A novel protein, MCM binding protein (MCM-BP), was identified as a component of the MCM complex.
  • MCM-BP forms a stable complex with MCM3-MCM7, replacing MCM2, and enhances complex stability.
  • MCM-BP-containing complexes retain helicase activity and associate with chromatin in a cell cycle-dependent manner, similar to other MCM subunits.
  • MCM-BP chromatin association is dependent on MCM4 and cdc6, and MCM-BP influences MCM4 chromatin loading.

Conclusions:

  • Multicellular eukaryotes possess two distinct types of hexameric MCM complexes with unique properties.
  • MCM-BP represents a novel regulatory component of the DNA replication machinery, influencing complex stability and chromatin association.

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