Topoisomerase IIα is essential for maintenance of mitotic chromosome structure

Topoisomerases are a family of proteins that alter DNA topology to accommodate for the stresses imparted by processes such as transcription, replication, and mitotic chromosome condensation. Topoisomerase 2A (TOP2A) is a key member of this family that prominently stains along the axis of mitotic chromosomes. Assessing mitotic-specific functions of TOP2A has been thwarted by the many essential roles the protein plays across the cell cycle. Our study used an ultrafast protein depletion system in human cells to dissect the mitotic-specific function of TOP2A. We have shown that TOP2A is necessary for keeping the structure of chromatids together once they have formed (maintenance), in addition to being involved in the establishment of the mitotic chromosome.