Internal Initiation of Translation Directed by the 5′-Untranslated Region of the Tobamovirus Subgenomic RNA I2

Скулачев, М. В.; Иванов, П.А.; Карпова, О. В.; Korpela, Timo; Родионова, Н. В.; Dorokhov, Yu. L.; Atabekov, J.G.

doi:10.1006/viro.1999.9928

Cited by 52 publications

(58 citation statements)

References 36 publications

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“…Other plant RNA virus 5Ј UTRs have elements with IRES-like activity as assayed using dual-reporter constructs, but the limited length of the region upstream of initiation codons suggests that small-subunit entry differs from that of animal virus IRESs (3,22,24,25,31,41,54,60,69). 5Ј elements with IRES-like activity in TEV and BRV contain polypyrimidine sequences that are complementary to a region of 18S rRNA that is known to be accessible to base pairing with an mRNA template (24,25,54,69). This has led to suggestions that small IRES-like elements in plant viruses may act by attracting 40S subunits through cRNA-RNA interactions, similar to the case for prokaryotic Shine-Dalgarno sequences (53).…”

Section: Discussionmentioning

confidence: 99%

“…Many plant virus 5Ј UTRs contain translational enhancers (5Ј TEs) comprising pseudoknots, or pyrimidine-rich or purine-rich unstructured sequences, some of which can direct translation of internal open reading frames (ORFs) in bicistronic mRNAs, a hallmark of IRES activity (24,25,31,41,54,60,69). Cellular mRNAs that are translated when cap-dependent translation is inhibited also contain IRESs of limited size in their 5Ј UTRs (6,15,27,33,50).…”

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confidence: 99%

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Ribosome Binding to a 5′ Translational Enhancer Is Altered in the Presence of the 3′ Untranslated Region in Cap-Independent Translation of Turnip Crinkle Virus

Stupina

Yuan

Meškauskas

et al. 2011

J Virol

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Plus-strand RNA viruses without 5 caps require noncanonical mechanisms for ribosome recruitment. A translational enhancer in the 3 untranslated region (UTR) of Turnip crinkle virus (TCV) contains an internal T-shaped structure (TSS) that binds to 60S ribosomal subunits. We now report that the 63-nucleotide (nt) 5 UTR of TCV contains a 19-nt pyrimidine-rich element near the initiation codon that supports translation of an internal open reading frame (ORF) independent of upstream 5 UTR sequences. Addition of 80S ribosomes to the 5 UTR reduced the flexibility of the polypyrimidine residues and generated a toeprint consistent with binding to this region. Binding of salt-washed 40S ribosomal subunits was reduced 6-fold when the pyrimidinerich sequence was mutated. 40S subunit binding generated the same toeprint as 80S ribosomes but also additional ones near the 5 end. Generation of out-of-frame AUGs upstream of the polypyrimidine region reduced translation, which suggests that 5-terminal entry of 40S subunits is followed by scanning and that the polypyrimidine region is needed for an alternative function that requires ribosome binding. No evidence for RNA-RNA interactions between 5 and 3 sequences was found, suggesting that TCV utilizes an alternative means for circularizing its genome. Combining 5 and 3 UTR fragments in vitro had no discernible effect on the structures of the RNAs. In contrast, when 80S ribosomes were added to both fragments, structural changes were found in the 5 UTR polypyrimidine tract that were not evident when ribosomes interacted with the individual fragments. This suggests that ribosomes can promote an interaction between the 5 and 3 UTRs of TCV.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Ribosome Binding to a 5′ Translational Enhancer Is Altered in the Presence of the 3′ Untranslated Region in Cap-Independent Translation of Turnip Crinkle Virus

Stupina

Yuan

Meškauskas

et al. 2011

J Virol

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“…Recently, a new tobamovirus [cruciferinfecting tobamovirus (crTMV)] capable of systemically infecting members of the Brassicaceae family has been isolated and characterized (21). We reported that the 148-nt region upstream of the CP gene of crTMV RNA contains an IRES (IRES CP,148 CR ), promoting cap-independent and internal translation of the CP gene and different reporter genes from dicistronic constructs (22,23). Recently, the ability of IRES CP,148 CR to promote internal translation was confirmed in a potato virus X vector-based system (24 CR exhibited a high capacity to mediate translation of the 3Ј-proximal ␤-glucuronidase (GUS) gene located on a dicistronic transcript in all of the types of cells tested.…”

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confidence: 99%

Polypurine (A)-rich sequences promote cross-kingdom conservation of internal ribosome entry

Dorokhov

Скулачев

Иванов

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

122

113

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. Remarkably, even homopolymeric poly(A) was moderately active, whereas a poly(G) homopolymer was not active. Furthermore, a database search for existing PARS sequences in 5-untranslated regions (5UTR) of genes in tobacco genome allowed the easy identification of a number of IRES candidates, in particular in the 5UTR of the gene encoding Nicotiana tabacum heat-shock factor 1 (NtHSF1). Consistent with our prediction, the 5UTR of NtHSF1 turned out to be an IRES element active in vitro, in plant protoplasts and HeLa cells. We predict that PARS elements, when found in other mRNAs, will show a similar activity.

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“…In particular, an IRES element derived from the coat protein gene of the crucifer Tobacco Mosaic Virus (cr-TMV) has been used for polycistronic gene expression in plants (Ha et al 2010;Skulachev et al 1999). Yamamoto et al used the cr-TMV IRES to selectively express a firefly luciferase gene from a single mRNA that also encoded a Renilla luciferase gene positioned 5′ to the firefly gene (Yamamoto et al 2003).…”

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confidence: 99%

Polycistronic expression of RNA silencing suppressor protects its own mRNA from RNA silencing

Kurihara

Okubo-Kurihara

Matsui

2015

Plant Biotechnology

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The internal ribosome entry site (IRES) enables polycistronic expression of multiple genes from a single mRNA controlled by one promoter. In general, only the most 5′ coding sequence is abundantly translated from polycistronic mRNAs in eukaryotic cells; IRES-mediated translation allows additional coding sequences at other positions to be translated at detectable levels. However, IRES-mediated translation often results in much lower protein expression than translation of single-gene mRNAs. We first aimed to improve IRES-mediated gene expression with a transient expression system based on Nicotiana benthamiana. We demonstrated that the presence of two cassettes comprised of an IRES-mediated Venus coding sequence results in higher Venus expression than one cassette. The double IRES cassette system is expected to be useful for expressing a gene of interest polycistronically in plants. Using the double IRES cassette system, we found that polycistronic expression of a reporter gene and two copies of an IRES-mediated RNA silencing suppressor gene protected the transcribed mRNA from RNA silencing-mediated degradation. This is the first report of a mRNA self-protection system from RNA silencing by IRES-mediated expression of a viral suppressor in plants.

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Internal Initiation of Translation Directed by the 5′-Untranslated Region of the Tobamovirus Subgenomic RNA I2

Cited by 52 publications

References 36 publications

Ribosome Binding to a 5′ Translational Enhancer Is Altered in the Presence of the 3′ Untranslated Region in Cap-Independent Translation of Turnip Crinkle Virus

Ribosome Binding to a 5′ Translational Enhancer Is Altered in the Presence of the 3′ Untranslated Region in Cap-Independent Translation of Turnip Crinkle Virus

Polypurine (A)-rich sequences promote cross-kingdom conservation of internal ribosome entry

Polycistronic expression of RNA silencing suppressor protects its own mRNA from RNA silencing

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