Stochastic motion and transcriptional dynamics of pairs of distal DNA loci on a compacted chromosome

David B Brueckner (1) , Hongtao Chen (2, 3) , Lev Barinov (2) , Benjamin Zoller (4, 2) , Thomas Gregor (2, 4)

1 IST Austria - Institute of Science and Technology [Klosterneuburg, Austria]
2 DPPU - Department of Physics, Princeton University
3 Lewis-Sigler Institute for Integrative Genomics
4 Physique des fonctions biologiques / Physics of Biological Functions

Chromosomes in the eukaryotic nucleus are highly compacted. However, for many functional processes, including transcription initiation, the 3D pair-wise motion of distal chromosomal elements, such as enhancers and promoters, is essential and necessitates dynamic fluidity. Therefore, the interplay of chromosome organization and dynamics is crucial for gene regulation. Here, we use a live imaging assay to simultaneously measure the positions of pairs of enhancers and promoters and their transcriptional output in the developing fly embryo while systematically varying the genomic separation between these two DNA loci. Our analysis reveals a combination of a compact globular organization and fast subdiffusive dynamics. These combined features cause an anomalous scaling of polymer relaxation times with genomic separation and lead to long-ranged correlations compared to existing polymer models. This scaling implies that encounter times of DNA loci are much less dependent on genomic separation than predicted by existing polymer models, with potentially significant consequences for eukaryotic gene expression.

Domaines: Biophysique

David B Brueckner, Hongtao Chen, Lev Barinov, Benjamin Zoller, Thomas Gregor. Stochastic motion and transcriptional dynamics of pairs of distal DNA loci on a compacted chromosome. 2023. ⟨pasteur-03988837v1⟩