Transmission of DNA requires that the sister chromosomes are pulled to opposite poles of the cell before division. Eukaryotic cells have a specific spindle apparatus which anchors the chromosomes during mitosis, but no analogous structure has been identified during chromosome segregation in bacteria. In the December 19 Sciencexpress, Sigal Ben-Yehuda and colleagues at Harvard University, USA, show that RacA is a bacterial protein that anchors chromosomes to the cell poles (Sciencexpress, 10.1126/science.1079914, December 19, 2002).

Ben-Yehuda et al. examined the genes and proteins involved in the sporulation in Bacillus subtilis and observed that a protein named RacA (for remodeling and anchoring of the chromosome) is required for the formation of the axial filament and for anchoring the origin regions at the cell poles. They suggest that RacA assembles into an adhesive patch at a centromere-like element near the origin, causing chromosomes to stick at the...