Recognition of eIF4G by Rotavirus NSP3 Reveals a Basis for mRNA Circularization

Groft, Caroline M.; Burley, S.K.

doi:10.1016/s1097-2765(02)00555-5

Cited by 123 publications

(115 citation statements)

References 51 publications

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“…Rotavirus mRNAs end in a consensus sequence that is bound by the NSP3 viral protein (48). The NSP3 protein interacts with the 40-amino-acid PABP binding domain in eIF-4G, with a motif that has no obvious similarity to the eIF-4G binding domain in PABP (47,62), although it binds to the same site (19). There is no similarity between the sequence required for translation activation by SLBP and the eIF-4G binding sequences in either PABP or NSP3.…”

mentioning

confidence: 99%

The Stem-Loop Binding Protein Is Required for Efficient Translation of Histone mRNA In Vivo and In Vitro

Sánchez

Marzluff

2002

Molecular and Cellular Biology

120

186

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Metazoan replication-dependent histone mRNAs end in a conserved stem-loop rather than in the poly(A) tail found on all other mRNAs. The 3 end of histone mRNA binds a single class of proteins, the stem-loop binding proteins (SLBP). In Xenopus, there are two SLBPs: xSLBP1, the homologue of the mammalian SLBP, which is required for processing of histone pre-mRNA, and xSLBP2, which is expressed only during oogenesis and is bound to the stored histone mRNA in Xenopus oocytes. The stem-loop is required for efficient translation of histone mRNAs and substitutes for the poly(A) tail, which is required for efficient translation of other eucaryotic mRNAs. When a rabbit reticulocyte lysate is programmed with uncapped luciferase mRNA ending in the histone stem-loop, there is a three-to sixfold increase in translation in the presence of xSLBP1 while xSLBP2 has no effect on translation. Neither SLBP affected the translation of a luciferase mRNA ending in a mutant stem-loop that does not bind SLBP. Capped luciferase mRNAs ending in the stem-loop were injected into Xenopus oocytes after overexpression of either xSLBP1 or xSLBP2. Overexpression of xSLBP1 in the oocytes stimulated translation, while overexpression of xSLBP2 reduced translation of the luciferase mRNA ending in the histone stem-loop. A small region in the N-terminal portion of xSLBP1 is required to stimulate translation both in vivo and in vitro. An MS2-human SLBP1 fusion protein can activate translation of a reporter mRNA ending in an MS2 binding site, indicating that xSLBP1 only needs to be recruited to the 3 end of the mRNA but does not need to be directly bound to the histone stem-loop to activate translation.Replication-dependent histone mRNAs are unique among metazoan mRNAs because they are not polyadenylated but end, instead, in a highly conserved stem-loop (35). In contrast, histone mRNAs from fungi and plants are polyadenylated. Histone pre-mRNA processing requires only a single endonucleolytic cleavage to form the 3Ј end of the mature mRNA immediately after a highly conserved stem-loop structure (16). Most of the regulation of histone mRNA levels is mediated by the stem-loop and occurs at the posttranscriptional level, via regulation of mRNA processing and stability (22,44). It is likely that the stem-loop also fulfills the essential functions that are performed by the poly(A) tail on other mRNAs. One of these functions is to enhance the efficiency of translation (27,52). For example, the stem-loop has been shown to promote localization of histone mRNAs to polyribosomes (56). mRNAs ending in the histone stem-loop at the 3Ј end are translationally more active than messages ending in other stem-loops when transfected into Chinese hamster ovary cells (15).By using the yeast three-hybrid system, proteins that bind to the stem-loop have been isolated from several species (34,55,64,66). Although only a single SLBP is present in mammals (34, 66), Drosophila (55), and Caenorhabditis elegans, frog oocytes (46) express two SLBPs, called xSLBP1 and xSLBP2 (64). The ...

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confidence: 99%

The Stem-Loop Binding Protein Is Required for Efficient Translation of Histone mRNA In Vivo and In Vitro

Sánchez

Marzluff

2002

Molecular and Cellular Biology

120

186

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“…Rotoviruses and influenza virus use a viral protein to structurally mimic PABP to recruit eIF4G (27,28). The picornavirus-like viruses in plants, the potyviruses, lack a cap at their 5Ј end but possess a virusencoded covalently linked protein (VPg) at the 5Ј end of the viral RNA (29).…”

Section: Satellite Tobacco Necrosis Virus (Stnv)mentioning

confidence: 99%

A Novel Interaction of Cap-binding Protein Complexes Eukaryotic Initiation Factor (eIF) 4F and eIF(iso)4F with a Region in the 3′-Untranslated Region of Satellite Tobacco Necrosis Virus

Gazo

Murphy

Gatchel

et al. 2004

Journal of Biological Chemistry

108

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Satellite tobacco necrosis virus (STNV)RNA is naturally uncapped at its 5 end and lacks polyadenylation at its 3 end. Despite lacking these two hallmarks of eukaryotic mRNAs, STNV-1 RNA is translated very efficiently. A ϳ130-nucleotide translational enhancer (TED), located 3 to the termination codon, is necessary for efficient cap-independent translation of STNV-1 RNA. The STNV-1 TED RNA fragment binds to the eukaryotic cap-binding complexes, initiation factor (eIF) 4F and eIF(iso)4F, as measured by nitrocellulose binding and fluorescence titration. STNV-1 TED is a potent inhibitor of in vitro translation when added in trans. This inhibition is reversed by the addition of eIF4F or eIF(iso)4F, and the subunits of eIF4F and eIF(iso)4F cross-link to STNV-1 TED, providing additional evidence that these factors interact directly with STNV-1 TED. Deletion mutagenesis of the STNV-1 TED indicates that a minimal region of ϳ100 nucleotides is necessary to promote cap-independent translation primarily through interaction with the cap binding subunits (eIF4E or eIF(iso)4E) of eIF4F or eIF(iso)4F.Initiation of protein synthesis in eukaryotic cells is a complicated process requiring 8 -10 initiation factors for proper alignment of the initiation codon of messenger RNA on the 40 S ribosome and subsequent joining of the 60 S ribosome (for review, see Refs. 1-6). For eukaryotes the first step in this process is the recognition of the m 7 GpppX cap structure at the 5Ј end of mRNA by eIF4E, 1 the cap-binding protein component of the eIF4F complex. The eIF4G component of eIF4F then acts as a scaffold for the assembly of other initiation factors (for review, see Refs. 7-11). Initiation factors eIF4A, eIF3, and poly(A)-binding protein (PABP) are known to interact with eIF4G during this process (for review, see Refs. 7, 9, and 10). PABP binds the poly(A) tail present at the 3Ј end of most cellular mRNAs, and the interaction of PABP with eIF4G implies that the 5Ј and 3Ј ends of the cellular mRNA are brought into close proximity during the initiation process (for review, see Refs. 9 and 12). This assembly of factors on the mRNA presumably functions in an ATP-dependent unwinding of secondary structure in the 5Ј-UTR of the mRNA before binding and scanning of the 40 S ribosome to find the correct initiation codon (5).Plant eIF4F consists of two subunits, a small cap-binding protein, eIF4E (26 kDa), and a large subunit, eIF4G (180 kDa). Higher plants possess an isozyme form of eIF4F, termed eIF(iso) 4F (13, 14). eIF(iso)4F, like eIF4F, consists of two subunits, eIF(iso)4E (28 kDa), and a large subunit, eIF(iso)4G (86 kDa). eIF(iso)4F has functions similar to eIF4F in the initiation of translation of plant mRNAs (14). The amino acid sequence of plant eIF(iso)4E is ϳ50% similar to plant eIF4E and retains all the conserved tryptophan residues found in cap-binding proteins (15,16). The large subunit, eIF(iso)4G, is significantly smaller than plant eIF4G (86 versus 180 kDa, (15)), sharing ϳ30 -40% similarity with central and C-terminal regions o...

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“…The region of NSP3 that is necessary for its interaction with RoXaN I includes a portion of the NSP3 dimerization domain and is close to the eIF4G-binding domain (44). Dimerization of NSP3 is required for its eIF4G-and RNAbinding properties (13,22,44), and consequently, for its biological properties (61). By interacting with NSP3, RoXaN I could impair the binding of eIF4G to NSP3, either by disrupting NSP3 dimers or by concealing its eIF4G-binding site.…”

Section: Vol 78 2004mentioning

confidence: 99%

“…In rotavirus-infected cells, NSP3 binds the 3Ј end of rotavirus mRNAs (46) and coimmunoprecipitates with eIF4G (45). NSP3 interacts with the same region of eIF4G as does PABP (22,29,45), but with a higher affinity (22). Therefore, during rotavirus infection, NSP3 evicts PABP from eIF4G, leading to the enhancement of translation of rotavirus mRNAs and the concomitant impairment of translation of cellular mRNAs (45,60).…”

mentioning

confidence: 99%

“…The carboxy-terminal 110 aa of NSP3 are required for binding to eIF4G I in a two-hybrid assay and for coimmunoprecipitation analysis (44,45). The three-dimensional structure of the carboxy terminus of NSP3 (aa 206 to 313) also shows that NSP3 is a dimer when bound to eIF4G I (aa 132 to 160), but contacts between NSP3 and eIF4G are limited to the carboxy-terminal 50 aa of NSP3 (22). NSP3-mediated stimulation of translation requires the simultaneous binding of NSP3 to mRNA and eIF4G, since deletion of either the amino-or carboxy-terminal domain abolishes translation enhancement (61).…”

mentioning

confidence: 99%

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RoXaN, a Novel Cellular Protein Containing TPR, LD, and Zinc Finger Motifs, Forms a Ternary Complex with Eukaryotic Initiation Factor 4G and Rotavirus NSP3

Vitour

Livet

Vende

et al. 2004

J Virol

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Rotavirus mRNAs are capped but not polyadenylated, and viral proteins are translated by the cellular translation machinery. This is accomplished through the action of the viral nonstructural protein NSP3, which specifically binds the 3 consensus sequence of viral mRNAs and interacts with the eukaryotic translation initiation factor eIF4G I. To further our understanding of the role of NSP3 in rotavirus replication, we looked for other cellular proteins capable of interacting with this viral protein. Using the yeast two-hybrid assay, we identified a novel cellular protein-binding partner for rotavirus NSP3. This 110-kDa cellular protein, named RoXaN (rotavirus X protein associated with NSP3), contains a minimum of three regions predicted to be involved in protein-protein or nucleic acid-protein interactions. A tetratricopeptide repeat region, a proteinprotein interaction domain most often found in multiprotein complexes, is present in the amino-terminal region. In the carboxy terminus, at least five zinc finger motifs are observed, further suggesting the capacity of RoXaN to bind other proteins or nucleic acids. Between these two regions exists a paxillin leucine-aspartate repeat (LD) motif which is involved in protein-protein interactions. RoXaN is capable of interacting with NSP3 in vivo and during rotavirus infection. Domains of interaction were mapped and correspond to the dimerization domain of NSP3 (amino acids 163 to 237) and the LD domain of RoXaN (amino acids 244 to 341). The interaction between NSP3 and RoXaN does not impair the interaction between NSP3 and eIF4G I, and a ternary complex made of NSP3, RoXaN, and eIF4G I can be detected in rotavirus-infected cells, implicating RoXaN in translation regulation.Rotaviruses, the major cause of diarrhea in young animals and children, are involved in the death of more than 400,000 children under the age of five each year (40, 41). Rotaviruses are members of the Reoviridae family, and their genomes are composed of 11 segments of double-stranded RNA which encode six structural proteins and five or six nonstructural proteins. The viral replication cycle occurs entirely in the cytoplasm. Upon virus entry, the viral transcriptase synthesizes capped, but nonpolyadenylated, mRNAs (16,28). These molecules are competent to serve as templates for either translation or replication. A subset of viral mRNAs are packaged into core particles and replicated to form the genomic doublestranded RNAs of progeny virions. Morphogenesis continues and viral proteins are added to generate the middle and outer layers surrounding the core particle. Mature virions, which consist of triple-layered particles, are released from the cell by lysis (reviewed in reference 16).Cellular translation involves a myriad of proteins and elements found at both the 5Ј and 3Ј termini of the majority of cellular mRNAs in a highly regulated cascade, controlled by specific protein-RNA and protein-protein interactions. In the steps leading to translational initiation, the cap structure at the 5Ј terminus of a...

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Recognition of eIF4G by Rotavirus NSP3 Reveals a Basis for mRNA Circularization

Cited by 123 publications

References 51 publications

The Stem-Loop Binding Protein Is Required for Efficient Translation of Histone mRNA In Vivo and In Vitro

The Stem-Loop Binding Protein Is Required for Efficient Translation of Histone mRNA In Vivo and In Vitro

A Novel Interaction of Cap-binding Protein Complexes Eukaryotic Initiation Factor (eIF) 4F and eIF(iso)4F with a Region in the 3′-Untranslated Region of Satellite Tobacco Necrosis Virus

RoXaN, a Novel Cellular Protein Containing TPR, LD, and Zinc Finger Motifs, Forms a Ternary Complex with Eukaryotic Initiation Factor 4G and Rotavirus NSP3

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