Cell Biology

Pole to Pole

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Science  29 Jul 2005:
Vol. 309, Issue 5735, pp. 673
DOI: 10.1126/science.309.5735.673b

Bacillus subtilis is a rod-shaped bacterium that is competent to bind, internalize, and eventually incorporate DNA in a process known as transformation. Hahn et al.describe the localization of three competence-mediating proteins and find that they are preferentially associated with the poles of the cells in a dynamic fashion. Using laser tweezers to manipulate single fluorescent DNA molecules, they observed that DNA binding and uptake occurs preferentially at the poles, too.

Kidane and Graumann also examine protein and DNA dynamics in B. subtilis. They find that the DNA recombination enzyme RecA colocalizes at the cell poles with one of the competence proteins, and during DNA uptake formed into threads. In comparison, another DNA recombination protein, RecN, was observed to oscillate from pole to pole on the scale of minutes; however, when DNA was added, RecN arrested at the same end where competence proteins were located, due to direct interaction with incoming DNA. The dynamic assembly and disassembly of the competence machinery are likely to govern exactly how transformable particular bacteria may be at a given time. — SMH

Cell 122, 59; 73 (2005).

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