ParM filaments (green) drive plasmid segregation.

Gerdes/Oxford

Polymerization of an actin-related protein may drive segregation of a bacterial plasmid, according to Jakob Møller-Jensen, Kenn Gerdes (University of Southern Denmark, Odense, Denmark), and colleagues.

Segregation in bacteria was thought to be a rather passive affair, with DNA attaching to the membrane and getting dragged along as cell growth led to membrane expansion. That model was challenged when DNA replication was found to be localized to one area at the cell center, followed by rapid movement of both plasmids and chromosomal DNA from midcell to more polar sites.

In the meantime, Gerdes had been working on the segregation requirements for the R1 plasmid. He had found that ParR binds to the parC centromere-like site on the plasmid, and that ParM binds to ParR. Then, Møller-Jensen tried detecting native ParM directly, using immunofluorescence, and saw axial filaments in...

The Rockefeller University Press
2002
The Rockefeller University Press
2002
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