Abstract
The stability of RNA polymerase II (Pol II) is tightly regulated during transcriptional elongation for proper control of gene expression. Our recent studies revealed that promoter-proximal Pol II is destabilized via the ubiquitin E3 ligase cullin 3 (CUL3) upon loss of transcription elongation factor SPT5. Here, we investigate how CUL3 recognizes chromatin-bound Pol II as a substrate. Using an unbiased proteomic screening approach, we identify armadillo repeat-containing 5 (ARMC5) as a CUL3 adaptor required for VCP/p97-dependent degradation of SPT5-depleted, chromatin-bound Pol II. Genome-wide analyses indicate that ARMC5 targets promoter-proximal Pol II in a BTB domain-dependent manner. Further biochemical analysis demonstrates that interaction between ARMC5 and Pol II requires the transcriptional cyclin-dependent kinase 9 (CDK9), supporting a phospho-dependent degradation model. We propose that defective, promoter-proximal Pol II that lacks SPT5 is rapidly eliminated from chromatin in a noncanonical early termination pathway that requires CDK9-dependent interaction with the CUL3-ARMC5 ubiquitin ligase complex.
| Original language | English (US) |
|---|---|
| Article number | eadt5885 |
| Journal | Science Advances |
| Volume | 11 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 24 2025 |
Funding
We thank S. G. Mackintosh, S. Byrum, and H. L. Douglas at the University of Arkansas for Medical Sciences IDeA National Resource for Quantitative Proteomics for mass spectrometry sample processing and analysis. We are grateful to B. Monroe for illustration in Fig. 5, to M. Das and M. Iwanaszko for next-generation sequencing data processing, and to the Shilatifard laboratory members for helpful discussions. This work was supported by National Cancer Institute Outstanding Investigator award R35-C A197569 (A.S.) and NIH/NIGMS grant R24GM137786 (IDeA National Resource for Quantitative Proteomics).
ASJC Scopus subject areas
- General