TRIM28 regulates RNA polymerase II promoter-proximal pausing and pause release

Area of Science:

• Molecular Biology
• Gene Regulation
• Transcriptional Control

Background:

• Promoter-proximal pausing of RNA polymerase II (Pol II) is a critical checkpoint in gene transcription.
• Identifying novel regulators of paused Pol II is essential for understanding gene expression control.

Purpose of the Study:

• To identify novel human proteins that regulate paused Pol II.
• To investigate the role of TRIM28 in Pol II pausing and transcriptional elongation.

Main Methods:

• Unbiased screening to identify Pol II regulators.
• In vitro and in vivo experiments assessing Pol II pausing.
• Genome-wide ChIP-sequencing to analyze Pol II occupancy.
• Mechanistic studies on transcription-coupled phosphorylation.

Main Results:

• TRIM28 was identified as a novel regulator of paused Pol II.
• TRIM28 depletion led to HSF1-dependent attenuation of Pol II pausing.
• TRIM28 knockdown resulted in de novo expression of HSPA1B and other genes regulated by paused Pol II.
• Genome-wide analyses revealed a global role for TRIM28 in regulating Pol II pausing and release.
• Transcription-coupled phosphorylation was implicated in TRIM28-mediated Pol II pause release.

Conclusions:

• TRIM28 is a novel factor that modulates Pol II pausing and transcriptional elongation.
• TRIM28 plays a significant role in regulating gene expression at a global level in mammals.
• Understanding TRIM28's function provides new insights into the mechanisms of transcriptional control.