New insights into ‘glue’ for DNA

Leicester scientist involved in discovery of how a component of the cohesin ring binds DNA.

A group of scientists, including a University of Leicester biologist, have revealed new insights into a protein that acts as a ‘glue’ for DNA.

Before cell division begins, a newly replicated chromosome consists of two identical threadlike strands that are joined together. Responsible for holding these sister chromatids together is a ring-shaped protein complex called cohesin, possibly by embracing them within its ring. However, how cohesin might directly recognise DNA was unknown. Now, Yan Li and colleagues working under the supervision of the University of Leicester’s Daniel Panne, who conducted the work while at EMBL Grenoble, have published the crystal structure of a cohesin subcomplex.

The study shows that this complex directly engages the double helix. A stretch of amino acids on the surface of the cohesin component effectively ‘glues’ to the DNA. Furthermore, in collaboration with the group of Christian Haering at EMBL Heidelberg, the scientists artificially altered these amino acids. This modified cohesin ring does not engage chromatids, thus preventing normal cell division.

The results – published in eLife – therefore reveal a direct DNA attachment site in the cohesin complex. Further studies on cohesin and its engagement to chromatids will lead to deeper mechanistic insights into how this machinery contributes to cell division.