scholarly journals The RNA pseudoknots in foot-and-mouth disease virus are dispensable for genome replication but essential for the production of infectious virus

2020 ◽  
Author(s):  
Joseph C. Ward ◽  
Lidia Lasecka-Dykes ◽  
Chris Neil ◽  
Oluwapelumi Adeyemi ◽  
Sarah Gold ◽  
...  

AbstractThe positive stranded RNA genomes of picornaviruses comprise a single large open reading frame flanked by 5′ and 3′ untranslated regions (UTRs). Foot-and-mouth disease virus (FMDV) has an unusually large 5′ UTR (1.3 kb) containing five structural domains. These include the internal ribosome entry site (IRES), which facilitates initiation of translation, and the cis-acting replication element (cre). Less well characterised structures are a 5′ terminal 360 nucleotide stem-loop, a variable length poly-C-tract of approximately 100-200 nucleotides and a series of two to four tandemly repeated pseudoknots (PKs). We investigated the structures of the PKs by selective 2′ hydroxyl acetylation analysed by primer extension (SHAPE) analysis and determined their contribution to genome replication by mutation and deletion experiments. SHAPE and mutation experiments confirmed the importance of the previously predicted PK structures for their function. Deletion experiments showed that although PKs are not essential for replication, they provide genomes with a competitive advantage. However, although replicons and full-length genomes lacking all PKs were replication competent, no infectious virus was rescued from genomes containing less than one PK copy. This is consistent with our earlier report describing the presence of putative packaging signals in the PK region.

2016 ◽  
Vol 90 (15) ◽  
pp. 6864-6883 ◽  
Author(s):  
Morgan R. Herod ◽  
Cristina Ferrer-Orta ◽  
Eleni-Anna Loundras ◽  
Joseph C. Ward ◽  
Nuria Verdaguer ◽  
...  

ABSTRACTThePicornaviridaeis a large family of positive-sense RNA viruses that contains numerous human and animal pathogens, including foot-and-mouth disease virus (FMDV). The picornavirus replication complex comprises a coordinated network of protein-protein and protein-RNA interactions involving multiple viral and host-cellular factors. Many of the proteins within the complex possess multiple roles in viral RNA replication, some of which can be provided intrans(i.e., via expression from a separate RNA molecule), while others are required incis(i.e., expressed from the template RNA molecule).In vitrostudies have suggested that multiple copies of the RNA-dependent RNA polymerase (RdRp) 3D are involved in the viral replication complex. However, it is not clear whether all these molecules are catalytically active or what other function(s) they provide. In this study, we aimed to distinguish between catalytically active 3D molecules and those that build a replication complex. We report a novel nonenzymaticcis-acting function of 3D that is essential for viral-genome replication. Using an FMDV replicon in complementation experiments, our data demonstrate that thiscis-acting role of 3D is distinct from the catalytic activity, which is predominantlytransacting. Immunofluorescence studies suggest that bothcis- andtrans-acting 3D molecules localize to the same cellular compartment. However, our genetic and structural data suggest that 3D interacts inciswith RNA stem-loops that are essential for viral RNA replication. This study identifies a previously undescribed aspect of picornavirus replication complex structure-function and an important methodology for probing such interactions further.IMPORTANCEFoot-and-mouth disease virus (FMDV) is an important animal pathogen responsible for foot-and-mouth disease. The disease is endemic in many parts of the world with outbreaks within livestock resulting in major economic losses. Propagation of the viral genome occurs within replication complexes, and understanding this process can facilitate the development of novel therapeutic strategies. Many of the nonstructural proteins involved in replication possess multiple functions in the viral life cycle, some of which can be supplied to the replication complex from a separate genome (i.e., intrans) while others must originate from the template (i.e., incis). Here, we present an analysis ofcisandtransactivities of the RNA-dependent RNA polymerase 3D. We demonstrate a novelcis-acting role of 3D in replication. Our data suggest that this role is distinct from its enzymatic functions and requires interaction with the viral genome. Our data further the understanding of genome replication of this important pathogen.


2003 ◽  
Vol 77 (3) ◽  
pp. 2243-2246 ◽  
Author(s):  
Laurence Tiley ◽  
Andrew M. Q. King ◽  
Graham J. Belsham

ABSTRACT A temperature-sensitive (ts) mutation was identified within the 5′-untranslated region of foot-and-mouth disease virus (FMDV) RNA. The mutation destabilizes a stem-loop structure recently identified as a cis-acting replication element (cre). Genetic analyses indicated that the ts defect in virus replication could be complemented. Thus, the FMDV cre can function in trans. It is suggested that the cre be renamed a 3B-uridylylation site (bus).


1995 ◽  
Vol 114 (1) ◽  
pp. 1-13 ◽  
Author(s):  
E. L. Woodbury

Foot-and-mouth disease (FMD) was the first animal disease to be attributed to a virus, and the second virus to be discovered [1]. It is a positive-sense, singlestranded RNA picornavirus and the sole member of the genus Aphthovirus. Each infectious virus particle contains a single strand of RNA approximately 8-5 kb long. This is translated into a single polypeptide which is then cleaved into the structural and non-structural virus proteins.


2002 ◽  
Vol 76 (19) ◽  
pp. 9686-9694 ◽  
Author(s):  
Peter W. Mason ◽  
Svetlana V. Bezborodova ◽  
Tina M. Henry

ABSTRACT Over the last few years, an essential RNA structure known as the cis-acting replicative element (cre) has been identified within the protein-coding region of several picornaviruses. The cre, a stem-loop structure containing a conserved AAACA motif, functions as a template for addition of U residues to the protein primer 3B. By surveying the genomes of representatives of several serotypes of foot-and-mouth disease virus (FMDV), we discovered a putative cre in the 5′ untranslated region of the genome (contiguous with the internal ribosome entry site [IRES]). To confirm the role of this putative cre in replication, we tested the importance of the AAACA motif and base pairing in the stem in FMDV genome replication. To this end, cre mutations were cloned into an FMDV replicon and into synthetic viral genomes. Analyses of the properties of these replicons and genomes revealed the following. (i) Mutations in the AAACA motif severely reduced replication, and all viruses recovered from genomes containing mutated AAACA sequences had reverted to the wild-type sequence. (ii) Mutations in the stem region showed that the ability to form this base-paired structure was important for replication. Although the cre was contiguous with the IRES, the mutations we created did not significantly reduce IRES-mediated translation in vivo. Finally, the position of the cre at the 5′ end of the genome was shown not to be critical for replication, since functional replicons and viruses lacking the 5′ cre could be obtained if a wild-type cre was added to the genome following the 3Dpol coding region. Taken together, these results support the importance of the cre in replication and demonstrate that the activity of this essential element does not require localization within the polyprotein-encoding region of the genome.


2006 ◽  
Vol 87 (10) ◽  
pp. 3013-3022 ◽  
Author(s):  
Paula Serrano ◽  
Miguel Rodriguez Pulido ◽  
Margarita Sáiz ◽  
Encarnacion Martínez-Salas

The untranslated regions (UTRs) of the foot-and-mouth disease virus (FMDV) genome contain multiple functional elements. In the 5′ UTR, the internal ribosome entry site (IRES) element governs cap-independent translation initiation, whereas the S region is presumably involved in RNA replication. The 3′ UTR, composed of two stem–loops and a poly(A) tract, is required for viral infectivity and stimulates IRES activity. Here, it was found that the 3′ end established two distinct strand-specific, long-range RNA–RNA interactions, one with the S region and another with the IRES element. These interactions were not observed with the 3′ UTR of a different picornavirus. Several results indicated that different 3′ UTR motifs participated in IRES or S region interactions. Firstly, a high-order structure adopted by both the entire IRES and the 3′ UTR was essential for RNA interaction. In contrast, the S region interacted with each of the stem–loops. Secondly, S–3′ UTR interaction but not IRES–3′ UTR interaction was dependent on a poly(A)-dependent conformation. However, no other complexes were observed in mixtures containing the three transcripts, suggesting that these regions did not interact simultaneously with the 3′ UTR probe. Cellular proteins have been found to bind the S region and one of these also binds to the 3′ UTR in a competitive manner. Our data suggest that 5′–3′-end bridging through both direct RNA–RNA contacts and RNA–protein interactions may play an essential role in the FMDV replication cycle.


2004 ◽  
Vol 85 (9) ◽  
pp. 2555-2565 ◽  
Author(s):  
Gergis Bassili ◽  
Eleni Tzima ◽  
Yutong Song ◽  
Lanja Saleh ◽  
Kerstin Ochs ◽  
...  

Foot-and-mouth disease virus (FMDV) and other picornaviruses initiate translation of their positive-strand RNA genomes at the highly structured internal ribosome entry site (IRES), which mediates ribosome recruitment to an internal site of the virus RNA. This process is facilitated by eukaryotic translation initiation factors (eIFs), such as eIF4G and eIF4B. In the eIF4G-binding site, a characteristic, discontinuous sequence element is highly conserved within the cardio- and aphthovirus subgroup (including FMDV) of the picornaviruses. This conserved element was mutated in order to investigate its primary sequence and secondary structure requirements for IRES function. Both binding of eIF4G to the IRES and IRES-directed translation are seriously impaired by mutations in two unpaired dinucleotide stretches that are exposed from the double-stranded (ds)RNA. In the base-paired regions of the conserved element, maintenance of the double-stranded secondary structure is essential, whilst in some cases, the primary sequence within the dsRNA regions is also important for IRES function. Extra eIF4F added to the translation reaction does not restore full IRES activity or eIF4G binding, indicating that disturbances in the structure of this conserved element cannot be overcome by increased initiation factor concentrations.


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