Waltz of the chromosomes

During interphase, chromosomes are supposed to be as immobile as a sailboat on a windless day. But according to a new study, chromosomes aremore active than anyone thought, hustling around the nucleus at a speed of up to three microns a minute. The nonrandom movements require energy and may prepare DNA for transcription, the researchers believe.

To track these movements, Susan Gasser of the University of Geneva (Geneva, Switzerland) and colleagues used GFP to tag four positions on two yeast chromosomes. Although the centromeres and telomeres are tethered to the edge of the nucleus and move little, the chromosomal arms are mobile and may traverse one third the diameter of the nucleus in as little as 10 s. Previous workers may not have noticed the movements because they are less obvious in the...