The exosome complex of 3'-5' exonucleases participates in RNA maturation and quality control and can rapidly degrade RNA-protein complexes in vivo. However, the purified exosome showed weak in vitro activity, indicating that rapid RNA degradation requires activating cofactors. This work identifies a nuclear polyadenylation complex containing a known exosome cofactor, the RNA helicase Mtr4p; a p...

The exosome is an exoribonuclease complex involved in the degradation and maturation of a wide variety of RNAs. The nine-subunit core of the eukaryotic exosome is catalytically inactive and may have an architectural function and mediate substrate binding. In Saccharomyces cerevisiae, the associated Dis3 and Rrp6 provide the exoribonucleolytic activity. The human exosome-associated Rrp6 counterp...

The exosome complex is involved in multiple RNA processing and degradation pathways. How exosome is recruited to particular RNA substrates and then chooses between RNA processing and degradation modes remains unclear. We find that the RNA binding protein Nrd1, complexed with its partners Nab3, Sen1, and cap binding complex, physically interacts with the nuclear form of exosome. Nrd1 stimulates ...

Background: The exosome complex plays key roles in RNA processing and degradation in Eukaryotes and Archaea. Outstanding structural studies identified multiple pathways for RNA substrates into the exosome in vitro, but identifying the pathway followed by individual RNA species in vivo remains challenging. Methods: We attempted to address this question using RNase protection. In vivo RNA-protein...

The exosome is a large protein complex conserved in all eukaryotes that possesses 3’-5’ exoribonuclease activity [1]. It is playing a major role in RNA turnover and surveillance as well as processing of stable RNA species [2,3,1,4,5]. The exosome is composed of six distinct subunits homologous to the catalytic domains of ring shaped phosphorolytic bacterial RNase PH and PNPase (Rrp41, Rrp42, Rr...

Nuclear RNA degradation pathways are highly conserved across eukaryotes and play important roles in RNA quality control. Key substrates for exosomal degradation include aberrant functional RNAs and cryptic unstable transcripts (CUTs). It has recently been reported that the nuclear exosome is inactivated during meiosis in budding yeast through degradation of the subunit Rrp6, leading to the stab...

The exosome, one of the main cellular ribonucleases in eukaryotes, is a multi-subunit complex of deep evolutionary origin. This complex has been extensively characterized in Saccharomyces cerevisae. Given the good conservation of exosome subunit sequences, it was widely accepted that the yeast exosome provided a good model for other eukaryotic species. Recent analysis of higher eukaryotic exoso...

Exosomes play important roles in cancer progression. Although its contents (e.g., proteins and microRNAs) have been focused on in cancer research, particularly as potential diagnostic markers, the exosome behavior and methods for exosome quantification remain unclear. In the present study, we analyzed the tumor-derived exosome behavior and assessed the quantification of exosomes in patient plas...

is presumably because defects in one exosome subunit The eukaryotic cell contains a wide variety of RNA specause a failure to assemble the exosome properly, and cies that are either processed from 39-extended precurthe exosome per se is required for viability. This conclusors or degraded in a 39-to-59 direction. How 39-to-59 sion is supported by the observations that inactivation processing is ...

Chromatin insulators are functionally conserved DNA-protein complexes situated throughout the genome that organize independent transcriptional domains. Previous work implicated RNA as an important cofactor in chromatin insulator activity, although the precise mechanisms are not yet understood. Here we identify the exosome, the highly conserved major cellular 3' to 5' RNA degradation machinery, ...