Probing chromatin condensation dynamics in live cells using interferometric scattering correlation spectroscopy.

Area of Science:

• Cell Biology
• Biophysics
• Microscopy

Background:

• Chromatin organization and dynamics are crucial for regulating nuclear processes.
• Examining chromatin nanostructures in living cells is challenging due to chromatin's diffusive motion.

Purpose of the Study:

• To introduce a novel label-free technique for spatially mapping nanoscopic chromatin configurations in live cells.
• To deduce chromatin condensation states and analyze chromatin dynamics over time.

Main Methods:

• Interferometric scattering correlation spectroscopy (iSCORS) was employed.
• The technique captures time-varying linear scattering signals from native chromatin motion on a millisecond timescale.
• Label-free optical microscopy was utilized.

Main Results:

• iSCORS successfully mapped nanoscopic chromatin configurations in unlabeled live cell nuclei.
• Spontaneous fluctuations in chromatin condensation and heterogeneous compaction levels were observed in interphase cells.
• Changes in iSCORS signals correlated with transcriptional activity upon transcription inhibition.

Conclusions:

• iSCORS is a powerful tool for visualizing dynamic chromatin nano-arrangements in live cells without labeling.
• The technique can probe nanoscopic chromatin structures and dynamics linked to transcriptional activities.
• This advancement has potential applications in studying chromatin remodeling during stem cell differentiation, mechanotransduction, and DNA repair.