Identification of minimum Rpn4-responsive elements in genes related to proteasome functions

The proteasome is an essential, 66-subunit protease that mediates ubiquitin-dependent proteolysis. The transcription factor Rpn4 regulates concerted expression of proteasome subunits to increase the proteasome by recognizing nonamer proteasome-associated control element (PACE) elements on the promoter regions. However, the genes for proteasome assembly chaperones and some of the subunits have no PACEs. Here we identified a minimal hexamer “PACE-core” sequence that responds to Rpn4. PACE-cores are found in many genes related to proteasome function including the assembly chaperones, but cannot substitute for PACE of the subunits. Our results add a new layer of complexity in transcriptional regulation of genes involved in protein degradation.