The yeast ESCRT complexes are involved in the regulation of transcription elongation

Abstract

Endosomal sorting complex required for transport (ESCRT) is involved in membrane protein degradation through the recognition and sorting of ubiquitylated cargo proteins into the multivesicular body before fusion with the lysosome/vacuole. However, recent studies have challenged this canonical cellular function of ESCRT and have implicated a role for this machinery in multiple intracellular pathways. Here, we provide evidence that ESCRT complexes contribute to the regulation of transcription elongation in Saccharomyces cerevisiae. Most strains deficient in each subunit of ESCRT-0, -I, -II, and -III showed significant sensitivity to 6-azauracil or mycophenolic acid, a phenotype associated with transcription elongation defects. Moreover, these deletion strains significantly reduced transcription activation through Gcn4, a regulator of the general amino acid control. The transcription factor Rim101, which is proteolytically activated through the multimerized component Vps32/Snf7 of ESCRT-III and its collaborative proteins, was not associated with transcription elongation or Gcn4 activation. In addition, we observed that ESCRT complexes were crosslinked at the 3' region of the coding sequence in the actively transcribed gene. In summary, these results suggest that ESCRT complexes promote genes transcription during the late stages of elongation and are required for transcription activation through Gcn4.