Defective RNA polymerase III is negatively regulated by the SUMO-Ubiquitin-Cdc48 pathway

Area of Science:

• Molecular Biology
• Cellular Regulation
• Biochemistry

Background:

• Transcription by RNA polymerase III (Pol III) is crucial for cellular function.
• Pol III dysfunction is linked to human neurodegenerative diseases.
• Regulation of Pol III transcription is poorly understood compared to Pol II.

Purpose of the Study:

• To investigate the regulatory mechanisms of Pol III transcription in Saccharomyces cerevisiae.
• To identify post-translational modifications and protein factors involved in Pol III regulation.

Main Methods:

• Yeast genetics and molecular biology techniques.
• Analysis of protein post-translational modifications (SUMOylation, ubiquitylation).
• Investigation of the role of the Cdc48/p97 segregase in Pol III regulation.

Main Results:

• Pol III is negatively regulated by Small Ubiquitin-like Modifier (SUMO)ylation in budding yeast.
• Pol III subunits are targeted by ubiquitylation and the Cdc48/p97 segregase.
• These modifications sequentially lead to proteasomal degradation of Pol III subunits, repressing transcription.

Conclusions:

• A novel regulatory pathway for Pol III transcription involving SUMOylation, ubiquitylation, and Cdc48/p97 has been uncovered.
• This pathway leads to the repression of Pol III transcription through subunit degradation.
• SUMO and ubiquitin pathways, along with Cdc48/p97, represent potential therapeutic targets for Pol III-related diseases.