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05:35
Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins
Published on: March 3, 2016
Centromere pairing by a plasmid-encoded type I ParB protein.
Simon Ringgaard1, Jan Löwe, Kenn Gerdes
1Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
The Journal of Biological Chemistry
|July 24, 2007
Summary
ParB protein mediates DNA fragment pairing, crucial for plasmid partitioning in Escherichia coli. This process requires the N-terminus of ParB for effective centromere pairing and higher-order complex formation.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The par2 locus in E. coli plasmid pB171 controls plasmid segregation.
- It encodes ParA and ParB proteins and cis-acting sites parC1 and parC2.
Purpose of the Study:
- To investigate the role of ParB in DNA fragment pairing.
- To determine the mechanism of plasmid partitioning mediated by the par2 locus.
Main Methods:
- In vitro DNA binding assays.
- Electron microscopy.
- Analysis of N-terminal truncated ParB mutants.
Main Results:
- ParB protein binds cooperatively to parC sites.
- ParB mediates binary and higher-order pairing of DNA fragments in vitro.
- The N-terminus of ParB is essential for DNA pairing activity.
Conclusions:
- ParB-mediated centromere pairing is a key step in plasmid partitioning.
- This mechanism is conserved in type I loci for bacterial plasmid segregation.
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