RNA polymerase II degradation in response to rapamycin is not mediated through ubiquitylation

Area of Science:

• Molecular Biology
• Yeast Genetics
• Biochemistry

Background:

• Rapamycin induces RNA polymerase II degradation and growth arrest in Saccharomyces cerevisiae.
• The regulatory mechanisms controlling this process remain largely unknown.

Purpose of the Study:

• To elucidate the regulatory pathway of rapamycin-induced RNA polymerase II degradation in yeast.
• To identify key factors involved in this stress response mechanism.

Main Methods:

• Investigated the role of peptidyl prolyl cis/trans isomerase Rrd1 in RNA polymerase II regulation.
• Assessed the dependence of degradation on RNA polymerase II polyubiquitylation and elongation factor Elc1.
• Analyzed alternative degradation pathways under different stress conditions.

Main Results:

• Demonstrated that Rrd1 is essential for rapamycin-induced RNA polymerase II degradation.
• Showed that this degradation is independent of RNA polymerase II polyubiquitylation.
• Confirmed that the elongation factor Elc1 is not required for this process.
• Identified at least two distinct pathways for RNA polymerase II degradation, stress-dependent.

Conclusions:

• The peptidyl prolyl cis/trans isomerase Rrd1 plays a critical role in regulating RNA polymerase II degradation.
• Yeast employs multiple, stress-specific pathways to degrade RNA polymerase II, offering insights into cellular stress responses.