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Updated: Jul 9, 2026
07:05
Single-Molecule Imaging of EWS-FLI1 Condensates Assembling on DNA
Published on: September 8, 2021
Dynamic Regulation of Endogenous Transcription Factor Hubs at Single-Molecule Resolution
Shawn Yoshida1,2, Yanghao Zhong1, Akiko Kumagai2
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA.
Summary
Transcription factors (TFs) form hubs essential for gene activation. This study reveals how oncogenic EWS::FLI1 forms unique hubs in Ewing sarcoma cells, offering new therapeutic targets.
Area of Science:
- Molecular Biology
- Cell Biology
- Biophysics
Background:
- Transcription factors (TFs) form hubs for gene activation.
- Characterizing TF hub dynamics requires high-resolution imaging, which is limited.
- Oncogenic fusion TF EWS::FLI1 is crucial in Ewing sarcoma.
Purpose of the Study:
- Investigate the biophysical behavior of endogenous EWS::FLI1 hubs.
- Understand the regulation and dissolution mechanisms of these hubs.
- Assess the impact of compounds on EWS::FLI1 hub formation and localization.
Main Methods:
- CRISPR/Cas9 genome editing for endogenous TF manipulation.
- Single-molecule microscopy for high-resolution imaging.
- Live-cell imaging to observe dynamic TF hub behavior.
Main Results:
- EWS::FLI1 forms sub-diffraction-limit hubs with unique dissolution mechanisms.
- Hub formation is a neomorphic trait of EWS::FLI1, not its parental proteins.
- EWS::FLI1 hubs dissolve during mitosis but associate with chromosomes, suggesting a bookmarking role.
- Nascent RNA destabilizes EWS::FLI1 hubs.
- Therapeutic compounds LY2835219 and trabectedin disrupt or mislocalize EWS::FLI1 hubs.
Conclusions:
- EWS::FLI1 exhibits unique hub dynamics distinct from simple liquid-liquid phase separation.
- EWS::FLI1 plays a role in mitotic bookmarking.
- Nascent RNA regulates EWS::FLI1 hub stability.
- Targeting EWS::FLI1 hubs shows therapeutic potential for Ewing sarcoma.
Keywords:
EWS::FLI1Ewing sarcomacondensatesphase separationsingle‐molecule microscopytranscription factor hubstranscriptional regulationMore Related Videos
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