Hepatitis C Virus Internal Ribosome Entry Site-Dependent Translation in
            <i>Saccharomyces cerevisiae</i>
            Is Independent of Polypyrimidine Tract-Binding Protein, Poly(rC)-Binding Protein 2, and La Protein

Rosenfeld, Amy; Racaniello, Vincent R.

doi:10.1128/jvi.79.16.10126-10137.2005

Cited by 28 publications

(28 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results may suggest that the HCV IRES requires a certain minimal threshold of base-pairing free energy for a functional interaction and/or that three consecutive G/C bases in helix 26 are specifically required for the 18S rRNA to base pair with the HCV IRES. It may be significant that some studies have reported that the HCV IRES can function in Saccharomyces cerevisiae (32,33). The yeast 18S rRNA contains a UUU sequence in the apical loop of helix 26, which may suggest that subdomain IIId of the IRES can base pair to 18S rRNA via G−U pairing.…”

Section: Resultsmentioning

confidence: 99%

Base pairing between hepatitis C virus RNA and 18S rRNA is required for IRES-dependent translation initiation in vivo

Matsuda

Mauro

2014

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

View full text Add to dashboard Cite

Degeneracy in eukaryotic translation initiation is evident in the initiation strategies of various viruses. Hepatitis C virus (HCV) provides an exceptional example-translation of the HCV RNA is facilitated by an internal ribosome entry site (IRES) that can autonomously bind a 40S ribosomal subunit and accurately position it at the initiation codon. This binding involves both ribosomal protein and 18S ribosomal RNA (rRNA) interactions. In this study, we evaluate the functional significance of the rRNA interaction and show that HCV IRES activity requires a 3-nt Watson-Crick base-pairing interaction between the apical loop of subdomain IIId in the IRES and helix 26 in 18S rRNA. Mutations of these nucleotides in either RNA dramatically disrupted IRES activity. The activities of the mutated HCV IRESs could be restored by compensatory mutations in the 18S rRNA. The effects of the 18S rRNA mutations appeared to be specific inasmuch as ribosomes containing these mutations did not support translation mediated by the wild-type HCV IRES, but did not block translation mediated by the cap structure or other viral IRESs. The present study provides, to our knowledge, the first functional demonstration of mRNA-rRNA base pairing in mammalian cells. By contrast with other rRNA-binding sites in mRNAs that can enhance translation as independent elements, e.g., the ShineDalgarno sequence in prokaryotes, the rRNA-binding site in the HCV IRES functions as an essential component of a more complex interaction.hepatitis C virus | 18S rRNA | IRES | base pairing | translation H CV is a single-stranded RNA virus that is a major cause of severe liver disease. The RNA genome contains a large ORF and expresses a single polypeptide that is processed into smaller proteins, which are necessary for replication and assembly of viral particles. The RNA genome is uncapped, and translation does not require the eukaryotic initiation factor 4F (eIF4F) complex (1), which mediates cap-dependent translation. Instead, translation is facilitated by an internal ribosome entry site (IRES) located in the 5′ nontranslated region (2, 3). Inasmuch as the production of all HCV proteins requires the HCV IRES, the HCV IRES is a therapeutic target (4).IRESs encompass a variety of initiation mechanisms and have been extensively studied in viruses, which often exploit the translation capabilities of the host for their own use (5-7). In many cases, the IRES mechanism complements the infection strategy of the virus. In the case of the HCV IRES and other IRESs of this type, the IRES can effectively recruit the host translation machinery by directly binding to 40S ribosomal subunits (1,(8)(9)(10)(11)(12). The HCV-ribosome interaction has been shown to require an interaction with ribosomal protein S25 (13) and can also involve the eIF3 complex, which increases the stability of the interaction (14). In the presence of ternary complex, which contains the initiator Met-tRNA, a preinitiation complex can assemble at the start site.Various studies have investigated the binding of ...

show abstract

Section: Resultsmentioning

confidence: 99%

Base pairing between hepatitis C virus RNA and 18S rRNA is required for IRES-dependent translation initiation in vivo

Matsuda

Mauro

2014

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

View full text Add to dashboard Cite

show abstract

“…Rosenfeld and Racaniello (2005) claimed that cleavage of dicistronic mRNA was ruled out in their study because translation of the 3′ cistron was not reduced by mutations that inactivate the nonsense-mediated decay pathway, but that pathway is not the only source of RNases in yeast. In the case of HCV, cleavage might even occur by magnesium-catalyzed autohydrolysis (Kieft et al, 1999).…”

Section: Last Thoughtsmentioning

confidence: 97%

Lessons (not) learned from mistakes about translation

Kozak

2007

Gene

View full text Add to dashboard Cite

“…69 Plasmids. Plasmids encoding the lacZ gene of Escherichia coli (monocistronic plasmid) or the bicistronic transcript of the ADE3 gene of S. cerevisiase, the HCV IRES including sequence encoding the first 120 amino acids of the HCV polyprotein fused with the second amino acid of β-galactosidase were previously described 38 and introduced into all stains by standard cation transformation. 69 Transformation.…”

Section: Methodsmentioning

confidence: 99%

“…The requirement for two subunits of eIF3, the eIF2-GTP-Met tRNA i ternary complex, and eIF5B in HCV mediated internal initiation has been investigated using a functional assay for IRES dependent translation in S. cerevisiae. 38 Both the a and j subunits of eIF3 are needed for efficient HCV IRES dependent initiation. The absence of eIF5B abrogates internal initiation mediated by the IRES, while alteration of the eIF2-GTP-Met tRNA i ternary complex reduces translation in a concentration dependent manner.…”

Section: Introductionmentioning

confidence: 99%

Components of the multifactor complex needed for internal initiation by the IRES of hepatitis C virus inSaccharomyces cerevisiae

Rosenfeld

Racaniello

2010

RNA Biology

Self Cite

View full text Add to dashboard Cite

Interaction between the 40S ribosomal subunit and the IRES of hepatitis C virus (HCV) is thought to be independent of initiation proteins, while joining of the 60S ribosomal subunit, and initiation of translation is dependent upon components of the translation machinery. An established in vivo functional assay for internal initiation mediated by the HCV IRES was used to identify proteins needed for IRES dependent translation in Saccharomyces cerevisiae strains possessing alterations of the translation machinery. Internal initiation dependent upon the HCV IRES was abrogated in strains lacking eIF5B, and reduced in strains with altered eIF3, either lacking the Hcr1p subunit, a component of eIF3 not previously known to interact with HCV RNA, or possessing an amino acid change in the Rpg1p subunit. The HCV RNA-induced conformational change in the 40S subunit might affect positioning of eIF3 and lead to different interactions between the ribosome, eIF3, and the multifactor complex. HCV IRES dependent initiation was unaffected in strains in which the concentration of the initiating tRNA was reduced. Alteration of the δ subunit of eIF2B, which leads to inefficient recycling, or substitution of aspartic acid for serine 51 of eIF2α had no effect on internal initiation. Production of human Pkr inhibited HCV IRES dependent initiation in yeast. The synthesis of Pkr in yeast is known to result in high levels of eIF2α phosphorylation, increased Gcn4p synthesis, and reduced ribosomal protein production. These alterations may explain the effect of Pkr synthesis on HCV IRES dependent initiation in yeast.

show abstract

Hepatitis C Virus Internal Ribosome Entry Site-Dependent Translation in Saccharomyces cerevisiae Is Independent of Polypyrimidine Tract-Binding Protein, Poly(rC)-Binding Protein 2, and La Protein

Cited by 28 publications

References 80 publications

Base pairing between hepatitis C virus RNA and 18S rRNA is required for IRES-dependent translation initiation in vivo

Base pairing between hepatitis C virus RNA and 18S rRNA is required for IRES-dependent translation initiation in vivo

Lessons (not) learned from mistakes about translation

Components of the multifactor complex needed for internal initiation by the IRES of hepatitis C virus inSaccharomyces cerevisiae

Contact Info

Product

Resources

About