Chris Brackley "How do nucleosome positions control chromatin fibre structure and dynamics"

Chromatin is the substrate for all DNA-associated processes, and understanding its structural and dynamical properties is crucial for our understanding of gene regulation and other nuclear processes. It was once thought that chromatin would adopt very regular structures, for example, the 30-nm diameter solenoid-like fibres which were often presented in textbooks. But there is now much evidence which suggests that chromatin actually adopts a broad range of different structures within cells, and that these different structures play an important role in function. However, we do not have a clear understanding of what controls fibre structure and properties. I will present results from recent work which combines experiments and computer simulations to study the properties of artificial chromatin fibre constructs which mimic different types of chromatin. This shows that irregularity in nucleosome positioning can lead to broad and dynamic variation of many features of the resulting fibres, which, for example, could be the source of noise, cell-to-cell variability and plasticity in gene expression.