Messenger RNAs of Yeast Virus-Like Elements Contain Non-templated 5′ Poly(A) Leaders, and Their Expression Is Independent of eIF4E and Pab1

Vopálenský, Václav; Sýkora, Michal; Mašek, Tomáš; Pospíšek, Martin

doi:10.3389/fmicb.2019.02366

Cited by 7 publications

(4 citation statements)

References 121 publications

(190 reference statements)

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“…The TMV omega prime enhances translation via promoting the recruitment of the eIF4F complex [149,182]. Recently, it was found that mRNAs of yeast-virus-like elements contain a similar non-templated 5 -poly(A) leader, which also drives eIF4E-independent translation [183]. It is of note that these VACV post-replicative mRNAs have 5 -caps [184,185].…”

Section: Preferential Translation Of Vacv Mrnasmentioning

confidence: 99%

Vaccinia Virus as a Master of Host Shutoff Induction: Targeting Processes of the Central Dogma and Beyond

et al. 2020

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The synthesis of host cell proteins is adversely inhibited in many virus infections, whereas viral proteins are efficiently synthesized. This phenomenon leads to the accumulation of viral proteins concurrently with a profound decline in global host protein synthesis, a phenomenon often termed “host shutoff”. To induce host shutoff, a virus may target various steps of gene expression, as well as pre- and post-gene expression processes. During infection, vaccinia virus (VACV), the prototype poxvirus, targets all major processes of the central dogma of genetics, as well as pre-transcription and post-translation steps to hinder host cell protein production. In this article, we review the strategies used by VACV to induce host shutoff in the context of strategies employed by other viruses. We elaborate on how VACV induces host shutoff by targeting host cell DNA synthesis, RNA production and processing, mRNA translation, and protein degradation. We emphasize the topics on VACV’s approaches toward modulating mRNA processing, stability, and translation during infection. Finally, we propose avenues for future investigations, which will facilitate our understanding of poxvirus biology, as well as fundamental cellular gene expression and regulation mechanisms.

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Section: Preferential Translation Of Vacv Mrnasmentioning

confidence: 99%

Vaccinia Virus as a Master of Host Shutoff Induction: Targeting Processes of the Central Dogma and Beyond

et al. 2020

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“…It seems that genes of DNA polymerases have been pulled into VLEs that were sourced from a different origin. The research of Sýkora et al [ 65 ] and Vopálenský et al [ 66 ], who analyzed the transcriptional mechanism of pGKL from K. lactis , showed that RNA polymerase encoded on the autonomous molecules as well as the promoter sequences of all genes lying on both autonomous and non-autonomous molecules probably derived from the protoplast of poxviruses. Furthermore, the DNA polymerases found in viruses of the Poxviridae family do not show homology to the polymerases of VLEs origin.…”

Section: Resultsmentioning

confidence: 99%

New Cytoplasmic Virus-Like Elements (VLEs) in the Yeast Debaryomyces hansenii

Połomska

Neuvéglise

Zyzak

et al. 2021

Toxins

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Yeasts can have additional genetic information in the form of cytoplasmic linear dsDNA molecules called virus-like elements (VLEs). Some of them encode killer toxins. The aim of this work was to investigate the prevalence of such elements in D. hansenii killer yeast deposited in culture collections as well as in strains freshly isolated from blue cheeses. Possible benefits to the host from harboring such VLEs were analyzed. VLEs occurred frequently among fresh D. hansenii isolates (15/60 strains), as opposed to strains obtained from culture collections (0/75 strains). Eight new different systems were identified: four composed of two elements and four of three elements. Full sequences of three new VLE systems obtained by NGS revealed extremely high conservation among the largest molecules in these systems except for one ORF, probably encoding a protein resembling immunity determinant to killer toxins of VLE origin in other yeast species. ORFs that could be potentially involved in killer activity due to similarity to genes encoding proteins with domains of chitin-binding/digesting and deoxyribonuclease NucA/NucB activity, could be distinguished in smaller molecules. However, the discovered VLEs were not involved in the biocontrol of Yarrowia lipolytica and Penicillium roqueforti present in blue cheeses.

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“…Perhaps this property underlies the preferential translation of VACV mRNA during infection, as well as its resistance to cleavage by eIF4G and inhibition by cap analogs in vitro [ 42 , 43 ]. A similar situation takes place in the case of mRNA of yeast virus-like elements (VLE) pGKL1/2, which also have oligo(A)-leaders of variable length, but usually not exceeding 12 nt [ 44 ]. As with VACV, many VLE transcripts are uncapped, and thus their translation does not require eIF4E.…”

Section: “Deviant” Cap-dependent Initiation Employed By Viral Mrnasmentioning

confidence: 95%

Non-Canonical Translation Initiation Mechanisms Employed by Eukaryotic Viral mRNAs

Sorokin

Vassilenko

Terenin

et al. 2021

Biochemistry Moscow

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Viruses exploit the translation machinery of an infected cell to synthesize their proteins. Therefore, viral mRNAs have to compete for ribosomes and translation factors with cellular mRNAs. To succeed, eukaryotic viruses adopt multiple strategies. One is to circumvent the need for m 7 G-cap through alternative instruments for ribosome recruitment. These include internal ribosome entry sites (IRESs), which make translation independent of the free 5′ end, or cap-independent translational enhancers (CITEs), which promote initiation at the uncapped 5′ end, even if located in 3′ untranslated regions (3′ UTRs). Even if a virus uses the canonical cap-dependent ribosome recruitment, it can still perturb conventional ribosomal scanning and start codon selection. The pressure for genome compression often gives rise to internal and overlapping open reading frames. Their translation is initiated through specific mechanisms, such as leaky scanning, 43S sliding, shunting, or coupled termination-reinitiation. Deviations from the canonical initiation reduce the dependence of viral mRNAs on translation initiation factors, thereby providing resistance to antiviral mechanisms and cellular stress responses. Moreover, viruses can gain advantage in a competition for the translational machinery by inactivating individual translational factors and/or replacing them with viral counterparts. Certain viruses even create specialized intracellular “translation factories”, which spatially isolate the sites of their protein synthesis from cellular antiviral systems, and increase availability of translational components. However, these virus-specific mechanisms may become the Achilles’ heel of a viral life cycle. Thus, better understanding of the unconventional mechanisms of viral mRNA translation initiation provides valuable insight for developing new approaches to antiviral therapy.

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Messenger RNAs of Yeast Virus-Like Elements Contain Non-templated 5′ Poly(A) Leaders, and Their Expression Is Independent of eIF4E and Pab1

Cited by 7 publications

References 121 publications

Vaccinia Virus as a Master of Host Shutoff Induction: Targeting Processes of the Central Dogma and Beyond

Vaccinia Virus as a Master of Host Shutoff Induction: Targeting Processes of the Central Dogma and Beyond

New Cytoplasmic Virus-Like Elements (VLEs) in the Yeast Debaryomyces hansenii

Non-Canonical Translation Initiation Mechanisms Employed by Eukaryotic Viral mRNAs

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