Distinct modes of non-canonical initiation regulate selective host versus viral mRNA translation during poxvirus-induced shutoff
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ABSTRACT: Many viruses potently inhibit host protein synthesis while employing unconventional strategies to sustain their own translation, but how and why certain cellular mRNAs continue to be translated remains unclear. Here, we show that during shutoff by Vaccinia Virus (VacV) several host mRNAs increase in polysome occupancy but few, topped by JUN, result in increased protein abundance. Translation of viral mRNAs depended on the small ribosomal protein, Receptor for Activated C Kinase 1 (RACK1) and the eukaryotic Initiation Factor, eIF3. Cryo-electron microscopy (cryo-EM) further showed that eIF3 bound to virus-modified RACK1-containing 40S subunits that exhibit altered head rotation during infection. By contrast, RACK1 and eIF3 were dispensable for JUN translation. Moreover, structurally distinct 5’ untranslated regions (5’UTRs) in viral versus JUN mRNAs conferred differential eIF3 dependencies. Altogether, we reveal how distinct modes of non-canonical initiation support the production of both host and viral proteins that facilitate poxvirus replication despite infection-induced shutoff.
ORGANISM(S): Homo sapiens
PROVIDER: GSE278320 | GEO | 2024/10/30
REPOSITORIES: GEO
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