Trabajo presentado en el XV Workshop UNIA: Chromosomal architecture and topological stress, organizado por la Universidad Internacional de Andalucía, en Baeza (Jaén), del 8 al 10 de octubre de 2018
Interplay between chromatin and topological machineries is essential for genome architecture and function. Here we have addressed how chromatin and cohesins impact each other by either disrupting chromatin integrity in histone-depleted cells or cohesin activity in scc1-73 mutants. A dramatic loss of chromatin integrity has a minor effect in the binding and distribution of cohesins along the genome, pointing to DNA-associated specific features as major determinants for cohesin binding in vivo. On the contrary, a loss of cohesin activity alters nucleosome occupancy, especially at intergenic regions (IGRs). Interestingly, a highly significant number of these altered nucleosomes is also observed in histone-depleted cells, establishing a connection between cohesin activity and nucleosome assembly on chromatin integrity. In spite of the fact that most nucleosome alterations lie at IGRs, only a minor subset of them is associated with transcription misregulation. Indeed, we show that the loss of cohesin activity in scc1-73 affects the expression of a reduced number of genes (~10% of yeast genes) despite cohesins lie at 25% of the IGRs and can regulate genes located at cohesin-free regions. In sum, chromatin integrity is not a major determinant for cohesin binding, whereas cohesin activity does contribute to chromatin integrity