Decatenation G2 Checkpoint
A surveillance system that ensures that mitosis does not begin when topoisomerase IIα is locked in the closed clamp conformation by topoII catalytic inhibitors.
During DNA replication, daughter DNA duplexes become catenated or entangled through knots and links. These knots and links must be removed before sister chromatids can be properly segregated during mitosis. Type II DNA topoisomerases are enzymes that remove knots and links through a concerted set of reactions in which a protein-associated DNA double-strand break is generated, another segment of DNA is passed through the break, and the protein-associated double-strand break is reversed. The decatenation G2 checkpoint is an active signal transduction pathway that monitors topoisomerase IIα catalytic status and controls the location and/or activity of mitosis-promoting factor to delay the onset of mitosis.
Drugs that inhibit topoisomerase II fall into two groups known as poisons and...