S. cerevisiae Nab2-PrA interactomes in exosome, transport and ribosome biogenesis mutant backgrounds

ABSTRACT: RNA-binding proteins (RBPs) are key mediators of RNAbiogenesis and metabolism. An RBP can be dedicated to a specific transcript class (e.g. mRNAs) or function broadly across both coding and non-coding RNAs. Consequently, nuclear RNA homeostasis requires maintenance of bothRBP binding specificity and the proper distribution of RBP activity across multiple transcript classes. In S. cerevisiae, mutation of an RBP that functions in ribosome biogenesis, Enp1, was previously found to have terminal phenotypes similar to exosome or TRAMP mutants that extended beyond ribosomal RNA processing defects. Here, we show through proteomicand RNomic analyses that enp1-1 cells have stabilized polyadenylated pre-rRNAs that bind and sequester RBPs in the nucleolus, including the poly(A)-binding protein (PABP) Nab2. Changes in nucleolar polyadenylated RNA levels and PABP availability are further accompanied by transcriptome-wide changes in RNA biogenesis in enp1-1 cells, including increased levels of pervasive transcripts and snoRNA processing defects. The observed changes in RNA processing can be mitigated if enp1-1 cells are provided excess PABP activity through overexpression of Nab2 or Pab1. Together, these findings indicate that generation of excess nucleolar poly(A)-RNA is toxic to the cell, disrupting nuclear RNA processing homeostasis through sequestering RBPs, including the PABP Nab2.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Marlene Oeffinger  

LAB HEAD: Marlene Heloise Oeffinger

PROVIDER: PXD021855 | Pride | 2020-10-08

REPOSITORIES: Pride