A Molecular Titration System Coordinates Ribosomal Protein Gene Transcription with Ribosomal RNA Synthesis

• DOI: 10.1016/j.molcel.2016.10.003
• Publication Date: 2016-11-03T17:45:23Z
• Authors: Benjamin Albert; Britta Knight; Jason Merwin; Victoria Martin; Diana Ottoz; Yvonne Gloor; Maria Jessica Bru...; Adam Rudner; David Shore
• Keywords: Ribosomal Proteins; 0301 basic medicine; Organelle Biogenesis; Saccharomyces cerevisiae Proteins; Transcription, Genetic; Saccharomyces cerevisiae; 03 medical and health sciences; RNA Polymerase I; RNA, Ribosomal; Gene Expression Regulation, Fungal; Trans-Activators; Promoter Regions, Genetic; Ribosomes; Protein Binding

Cell growth potential is determined by the rate of ribosome biogenesis, a complex process that requires massive and coordinated transcriptional output. In the yeast Saccharomyces cerevisiae, ribosome biogenesis is highly regulated at the transcriptional level. Although evidence for a system that coordinates ribosomal RNA (rRNA) and ribosomal protein gene (RPG) transcription has been described, the molecular mechanisms remain poorly understood. Here we show that an interaction between the RPG transcriptional activator Ifh1 and the rRNA processing factor Utp22 serves to coordinate RPG transcription with that of rRNA. We demonstrate that Ifh1 is rapidly released from RPG promoters by a Utp22-independent mechanism following growth inhibition, but that its long-term dissociation requires Utp22. We present evidence that RNA polymerase I activity inhibits the ability of Utp22 to titrate Ifh1 from RPG promoters and propose that a dynamic Ifh1-Utp22 interaction fine-tunes RPG expression to coordinate RPG and rRNA transcription.