Periodic Reporting for period 4 - ChromatidCohesion (Establishment of Sister Chromatid Cohesion)
Berichtszeitraum: 2020-04-01 bis 2022-03-31
Because of their fundamental contribution to DNA organisation within the cell nucleus and within chromosomes, cohesin impinges on almost all processes that happen on DNA. These include gene transcription, DNA repair, chromosome compaction and chromosome segregation. Also, because of this, mutations in cohesin or its regulators are responsible for a large range of human illnesses. These range from severe developmental disorders to tumourigensis.
Our aim is to provide molecular insight into the function of the cohesin complex, so that we understand how cells work with their genomes, both in health and disease.
- We have repeated the biochemical reconstitution using proteins from two different yeast species. This has shown the evolutionary conservation of the process, but also revealed important differences.
- We have characterised the role of a critical component of the DNA replication fork, Chl1, and its contribution to sister chromatid cohesion establishment by directly physically contacting the cohesin rings during DNA replication.
- To visualise the conformational dynamics of the cohesin ring, we have constructed variant cohesin complexes that have fluorophores attached at defined locations. We have begun to watch their conformational dynamics by both bulk and single molecule observations.
- We have uncovered how a chromatin remodeler plays a two-fold role in loading cohesin onto DNA. It acts as both, the chromatin receptor for the cohesin loader complex, as well as an active machine that generates a nucleosome-free region that is required as the substrate for cohesin loading.