RacA, a Bacterial Protein That Anchors Chromosomes to the Cell Poles

Ben-Yehuda, Sigal
Rudner, David Z.
Losick, Richard

Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material: www.sciencemag.org/cgi/content/full/1079914/DC1; Materials and Methods; Figs. S1 to S3; Tables S1 and S2; References

29 October 2002; accepted 4 December 2002

Published online 19 December 2002; 10.1126/science.1079914

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Science 299(5606):p 532-536, January 24, 2003.

Eukaryotic chromosomes are anchored to a spindle apparatus during mitosis, but no such structure is known during chromosome segregation in bacteria. When sister chromosomes are segregated during sporulation in Bacillus subtilis, the replication origin regions migrate to opposite poles of the cell. If and how origin regions are fastened at the poles has not been determined. Here we describe a developmental protein, RacA, that acts as a bridge between the origin region and the cell poles. We propose that RacA assembles into an adhesive patch at a centromere-like element near the origin, causing chromosomes to stick at the poles.