Stochastic analysis of nuclear chromatin dynamics
Dr Eldad Kepten will be visiting the Institute to meet with staff and present a Seminar at 11:30hrs in the Brian Heap Seminar Room.
If you would like to attend this Seminar or find out more, please contact the Host Dr Peter Fraser directly.
A canonical example of bio-complexity can be found in the cell nucleus, as accurate gene expression demands strong regulation of chromatin interactions (DNA with its accompanying molecules). Several studies have looked into the spatial organization of the chromatin chains and its relation to various nuclear functions. However, organization is both created and destroyed through motion – an aspect of chromatin activity that is still lacking accurate description.
We track the temporal dynamics of chromatin loci through single cell in vivo fluorescent microscopy, and subsequent image analysis. Once trajectories are gathered, it is possible to dive into the stochastic data and identify the relevant mathematical and physical picture for the system. Mathematical analysis shows that the diffusion of loci is described by fractional Brownian motion, compatible with polymer models. Surprisingly, down regulation of Lamin A, a central structural protein, transforms dynamics into rapid normal diffusion, in contradiction to naïve physical expectation. In addition, long range anisotropic correlations are seen between loci, leading to the identification of another super imposed diffusive process. The emerging dynamical picture of chromatin has significant biological implications regarding both the maintenance and modification of nuclear organization.