The cryo-EM resolution revolution and transcription complexes

Area of Science:

• Structural Biology
• Biochemistry
• Molecular Biology

Background:

• Direct electron detector technology and advanced imaging processing have significantly enhanced cryo-electron microscopy (cryo-EM) resolution.
• This 'resolution revolution' in cryo-EM has transformed structural biology, particularly for large and dynamic molecular complexes.
• Many transcription complexes, crucial for gene regulation, have historically resisted detailed structural analysis.

Purpose of the Study:

• To review recent advancements in understanding transcription complex structures using cryo-EM.
• To highlight the impact of the cryo-EM resolution revolution on structural biology.
• To focus on eukaryotic RNA polymerases, pre-initiation complexes, chromatin remodelers, and epigenetic regulators.

Main Methods:

• Single-particle cryo-electron microscopy (cryo-EM)
• Cryo-electron tomography (cryo-ET)
• Advanced image processing techniques

Main Results:

• Atomic or near-atomic resolution structures of large, flexible, and transient transcription complexes are now achievable.
• Cryo-EM has overcome previous limitations in determining structures of complexes that were intractable by crystallography.
• Detailed structural insights into eukaryotic RNA polymerases and associated regulatory factors are emerging.

Conclusions:

• The cryo-EM resolution revolution is a pivotal development for structural biology.
• It provides unprecedented opportunities to study the molecular mechanisms of transcription.
• Further structural studies will illuminate the regulation of gene expression and epigenetic processes.