Health

A tale of two forms of cohesin in DNA repair | Science

In a groundbreaking study published in the journal *Nature*, researchers have unveiled the intricate mechanisms by which two forms of cohesin—extrusive and cohesive cohesin—collaborate to repair double-strand breaks (DSBs) in DNA. Double-strand breaks are critical lesions that can lead to genomic instability and are implicated in various diseases, including cancer. The cohesin complex, traditionally known for its role in chromosome organization and segregation during cell division, has now been identified as a key player in the DNA repair process.

The study highlights how extrusive cohesin, which can extend away from the chromosomal axis, and cohesive cohesin, which holds sister chromatids together, work in tandem to facilitate the repair of DSBs. When a break occurs, extrusive cohesin actively engages in the recruitment of repair proteins to the site of damage, effectively acting as a molecular bridge. This action is crucial as it ensures that the necessary components for repair are concentrated at the break site, enhancing the efficiency of the repair process. Once the repair machinery is in place, cohesive cohesin stabilizes the structure, ensuring that the chromosomal integrity is maintained during and after the repair process.

This discovery not only sheds light on the fundamental processes of DNA repair but also opens new avenues for understanding how errors in these mechanisms can lead to diseases. For instance, mutations in cohesin components have been linked to various cancers and developmental disorders. By elucidating the cooperative roles of extrusive and cohesive cohesin, this research lays the groundwork for potential therapeutic strategies aimed at targeting cohesin-related pathways in cancer treatment. Overall, the findings emphasize the complexity of cellular repair mechanisms and the importance of cohesin in maintaining genomic stability.

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