Effects of Transcription-Dependent Physical Perturbations on the Chromosome Dynamics in Living Cells

Recent studies with single-particle tracking in live cells have revealed that chromatin dynamics are directly affected by transcription. However, how transcription alters the chromatin movements followed by changes in the physical properties of chromatin has not been elucidated. Here, we measured diffusion characteristics of chromatin by targeting telomeric DNA repeats with CRISPR-labeling. We found that transcription inhibitors that directly block transcription factors globally increased the movements of chromatin, while the other inhibitor that blocks transcription by DNA intercalating showed an opposite effect. We hypothesized that the increased mobility of chromatin by transcription inhibition and the decreased chromatin movement by a DNA intercalating inhibitor is due to alterations in chromatin rigidity. We also tested how volume confinement of nuclear space affects chromatin movements. We observed decreased chromatin movements under osmotic pressure and with overexpressed chromatin architectural proteins that compact chromatin.

Automated summary

Recent studies have shown that transcription directly affects chromatin dynamics. This study measured the diffusion characteristics of chromatin and found that transcription inhibitors increase chromatin movement, while DNA intercalating inhibitors have the opposite effect. The study also investigated the impact of volume confinement in the nucleus on chromatin movements.