Dimerization processes for light-regulated transcription factor Photozipper visualized by high-speed atomic force...

Area of Science:

• Molecular biology
• Biophysics
• Microscopy

Background:

• Transcription factors (TFs) are crucial for regulating cellular functions through DNA binding.
• The molecular mechanisms of TF dimerization, essential for DNA binding, are not fully understood.

Purpose of the Study:

• To elucidate the molecular mechanisms of TF dimerization using a photoresponsive TF.
• To visualize the dynamic dimerization process and domain interactions within a TF.

Main Methods:

• High-speed atomic force microscopy (HS-AFM) was employed to observe TF dimerization in real-time.
• A photoresponsive TF, Photozipper (PZ), comprising LOV and bZIP domains, was utilized.
• Controlled dark-light cycling was applied to manipulate TF dimerization.

Main Results:

• HS-AFM successfully visualized monomeric and dimeric states of PZ molecules under varying light conditions.
• The dynamic process of PZ dimerization and reversible monomer-dimer transitions was captured.
• Detailed AFM imaging revealed that the bZIP domain's entanglement state is modulated by light, loosening and fluctuating around the LOV domain.

Conclusions:

• The study reveals the critical role of the bZIP domain in TF dimerization.
• Light-induced conformational changes in the bZIP domain directly influence TF dimerization.
• HS-AFM provides unprecedented insights into the real-time dynamics of TF oligomerization.