The nucleus is much more than a storage compartment for chromosomes: It also contains the complex machinery that produces transcripts of the genes that are currently needed and releases them into the cell body. Some of the proteins involved herein are not evenly distributed in the nucleus, but cluster at specific sites. A study by the universities of Würzburg, Heidelberg and Bonn with the help of Evotec SE at the Martinsried site now shows how these „flash mobs“ are regulated. In the long term, the results could also yield new therapeutic approaches for spinal muscular atrophy. They are published in the journal Cell Reports.