Abstract
Multiple unrelated polymer systems have evolved to partition DNA molecules between daughter cells at division. To better understand polymer-driven DNA segregation, we reconstituted the three-component segregation system of the R1 plasmid from purified components. We found that the ParR/parC complex can construct a simple bipolar spindle by binding the ends of ParM filaments, inhibiting dynamic instability, and acting as a ratchet permitting incorporation of new monomers and riding on the elongating filament ends. Under steady-state conditions, the dynamic instability of unattached ParM filaments provides the energy required to drive DNA segregation.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / chemistry*
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Actins / metabolism*
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Actins / ultrastructure
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Adenosine Triphosphate / metabolism
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Bacterial Proteins / metabolism
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Biopolymers
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DNA Topoisomerase IV / metabolism
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DNA, Bacterial / metabolism*
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Escherichia coli Proteins / chemistry*
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Escherichia coli Proteins / metabolism*
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Escherichia coli Proteins / ultrastructure
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Microspheres
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Protein Binding
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R Factors / genetics
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R Factors / metabolism*
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Repressor Proteins / metabolism
Substances
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Actins
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Bacterial Proteins
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Biopolymers
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DNA, Bacterial
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Escherichia coli Proteins
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ParM protein, E coli
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ParR protein, bacteria
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Repressor Proteins
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Adenosine Triphosphate
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DNA Topoisomerase IV