Transcription Elongation Can Affect Genome 3D Structure.

Area of Science:

• Molecular Biology
• Genomics
• Epigenetics

Background:

• The relationship between active transcription and the three-dimensional (3D) genome organization remains largely unclear.
• Understanding how dynamic processes like transcription influence chromatin architecture is crucial for comprehending gene regulation and cellular function.

Purpose of the Study:

• To investigate the impact of transcription, particularly during viral infection, on the 3D organization of the host cell genome.
• To elucidate the molecular mechanisms by which transcription elongation affects chromatin interactions and genome architecture.

Main Methods:

• Utilized influenza A virus (IAV) infection model to study transcription-induced chromatin reorganization.
• Analyzed changes in chromatin interactions, cohesin displacement from CTCF sites, and chromatin compartment switching.
• Examined the effects of both viral and non-viral transcription stimuli, as well as transcription elongation inhibition.

Main Results:

• Rampant transcription during IAV infection rapidly reorganizes host chromatin interactions, primarily at the ends of highly transcribed genes.
• Elongating RNA polymerase II displaces cohesin from CTCF sites in readthrough transcription regions, causing locus decompaction.
• Transcription elongation can switch heterochromatin from the inactive B to the active A compartment, facilitating transcription factor binding.

Conclusions:

• Transcription elongation by RNA polymerase II is a key driver of genome 3D architecture remodeling.
• Cohesin-mediated chromatin contacts are dynamically regulated by transcription elongation and inhibition.
• These findings reveal a direct link between transcriptional activity and large-scale genome organization.