Related Experiment Video
Updated: Jul 5, 2026

A Reporter Based Cellular Assay for Monitoring Splicing Efficiency
Published on: September 15, 2021
A role for ubiquitin in the spliceosome assembly pathway
Priya Bellare1, Eliza C Small, Xinhua Huang
1Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, 2205 Tech Drive, Evanston, Illinois 60208, USA.
Abstract:
The spliceosome uses numerous strategies to regulate its function in mRNA maturation. Ubiquitin regulates many cellular processes, but its potential roles during splicing are unknown. We have developed a new strategy that reveals a direct role for ubiquitin in the dynamics of splicing complexes. A ubiquitin mutant (I44A) that can enter the conjugation pathway but is compromised in downstream functions diminishes splicing activity by reducing the levels of the U4/U6-U5 small nuclear ribonucleoprotein (snRNP). Similarly, an inhibitor of ubiquitin's protein-protein interactions, ubistatin A, reduces U4/U6-U5 triple snRNP levels in vitro. When ubiquitin interactions are blocked, ATP-dependent disassembly of purified U4/U6-U5 particles is accelerated, indicating a direct role for ubiquitin in repressing U4/U6 unwinding. Finally, we show that the conserved splicing factor Prp8 is ubiquitinated within purified triple snRNPs. These results reveal a previously unknown ubiquitin-dependent mechanism for controlling the pre-mRNA splicing pathway.
Related Concept Videos
RNA Splicing
RNA Splicing
Pre-mRNA Processing: RNA Splicing
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
Regulation of Nuclear Protein Sorting

