University of California, Berkeley | Plant & Microbial Biology
A Two-Headed Monster to Avert Disaster: HBS1/SKI7 Is Alternatively Spliced to Build Eukaryotic RNA Surveillance Complexes.
| Title | A Two-Headed Monster to Avert Disaster: HBS1/SKI7 Is Alternatively Spliced to Build Eukaryotic RNA Surveillance Complexes. |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Authors | Brunkard JO, Baker B |
| Journal | Front Plant Sci |
| Volume | 9 |
| Pagination | 1333 |
| Date Published | 2018 |
| ISSN | 1664-462X |
| Abstract | <p>The cytosolic RNA exosome, a 3'→5' exoribonuclease complex, contributes to mRNA degradation in eukaryotes, limiting the accumulation of poorly-translated, improperly translated, or aberrant mRNA species. Disruption of cytosolic RNA exosome activity allows aberrant RNA species to accumulate, which can then be detected by host antiviral immune systems as a signature of pathogen infection, activating antiviral defenses. SKI7 is a critical component of the cytosolic RNA exosome in yeast, bridging the catalytic exoribonuclease core with the SKI2/SKI3/SKI8 adaptor complex that guides aberrant RNA substrates into the exosome. The ortholog of was only recently identified in humans as an alternative splice form of the gene, which encodes a decoding factor translational GTPase that rescues stalled ribosomes. Here, we identify the plant orthologs of . We found that HBS1 and SKI7 are typically encoded by alternative splice forms of a single locus, although some plant lineages have evolved subfunctionalized genes that apparently encode only HBS1 or only SKI7. In all plant lineages examined, the gene is subject to regulation by alternative splicing that can yield unproductive transcripts, either by removing deeply conserved SKI7 coding sequences, or by introducing premature stop codons that render susceptible to nonsense-mediated decay. Taking a comparative, evolutionary approach, we define crucial features of the SKI7 protein shared by all eukaryotes, and use these deeply conserved features to identify SKI7 proteins in invertebrate lineages. We conclude that SKI7 is a conserved cytosolic RNA exosome subunit across eukaryotic lineages, and that is consistently regulated by alternative splicing, suggesting broad coordination of nuclear and cytosolic RNA metabolism.</p> |
| DOI | 10.3389/fpls.2018.01333 |
| Alternate Journal | Front Plant Sci |
| PubMed ID | 30258456 |
| PubMed Central ID | PMC6143672 |
| Grant List | DP5 OD023072 / OD / NIH HHS / United States |