kohesinens

Kohesinens is a biological term referring to the protein complex responsible for holding sister chromatids together after DNA replication during cell division. This complex plays a crucial role in ensuring that each daughter cell receives a complete and accurate set of chromosomes. The cohesin complex is composed of several protein subunits, including SMC1, SMC3, SCC1 (also known as RAD21), and SCC3 (also known as STAG). These proteins assemble into a ring-like structure that encircles the two sister chromatids.

The loading of cohesin onto chromosomes occurs during the S phase of the cell cycle, coincident with DNA replication. It is then maintained throughout the G2 and M phases, with its removal carefully regulated to allow for proper chromosome segregation during anaphase. The dissolution of cohesin is primarily mediated by a protease called separase, which cleaves one of the cohesin subunits, thereby releasing the sister chromatids to move to opposite poles of the cell. Errors in cohesin function or regulation can lead to aneuploidy, a condition characterized by an abnormal number of chromosomes, which is often associated with developmental disorders and cancer. Consequently, cohesin is a vital component of cell cycle control and genome stability.