Activation of a novel ubiquitin-independent proteasome pathway when RNA polymerase II encounters a protein roadblock.

ABSTRACT: Topoisomerase II? (Top2?)-DNA cleavage complexes are known to arrest elongating RNA polymerase II (RNAPII), triggering a proteasomal degradation of the RNAPII large subunit (RNAPII LS) and Top2? itself as a prelude to DNA repair. Here, we demonstrate that the degradation of Top2? occurs through a novel ubiquitin-independent mechanism that requires only 19S AAA ATPases and 20S proteasome. Our results suggest that 19S AAA ATPases play a dual role in sensing the Top2? cleavage complex and coordinating its degradation by 20S proteasome when RNAPII is persistently stalled by the Top2? protein roadblock. Clarification of this transcription-associated proteasome pathway could shed light on a general role of 19S AAA ATPases in processing tight protein-DNA complexes during transcription elongation.

SUBMITTER: Ban Y 

PROVIDER: S-EPMC3811683 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature