Recruitment of a 19 S Proteasome Subcomplex to an Activated Promoter

Abstract

The 19 S proteasome regulatory particle plays a critical role in cellular proteolysis. However, recent reports have demonstrated that 19 S proteins play a nonproteolytic role in nucleotide excision repair and transcription elongation. We show by chromatin immunoprecipitation assays that proteins comprising the 19 S complex are recruited to the GAL1-10 promoter by the Gal4 transactivator upon induction with galactose. This recruited complex does not contain proteins from the 20 S proteolytic particle and includes a subset of the 19 S proteins. This subset is also specifically retained from an extract by the Gal4 activation domain. These data indicate that in vivo, the base of the 19 S complex functions independently of the larger complex and plays a direct, nonproteolytic role in RNA polymerase II transcription.