Foot-and-Mouth Disease Virus, but Not Bovine Enterovirus, Targets the Host Cell Cytoskeleton via the Nonstructural Protein 3C
            <sup>pro</sup>

Foot-and-mouth disease virus (FMDV), the causative agent of foot-and-mouth disease, is an Aphthovirus within the Picornaviridae family. During infection with FMDV, several host cell membrane rearrangements occur to form sites of viral replication. FMDV protein 2C is part of the replication complex and thought to have multiple roles during virus replication. To better understand the role of 2C in the process of virus replication, we have been using a yeast two-hybrid approach to identify host proteins that interact with 2C. We recently reported that cellular Beclin1 is a natural ligand of 2C and that it is involved in the autophagy pathway, which was shown to be important for FMDV replication. Here, we report that cellular vimentin is also a specific host binding partner for 2C. The 2C-vimentin interaction was further confirmed by coimmunoprecipitation and immunofluorescence staining to occur in FMDV-infected cells. It was shown that upon infection a vimentin structure forms around 2C and that this structure is later resolved or disappears. Interestingly, overexpression of vimentin had no effect on virus replication; however, overexpression of a truncated dominant-negative form of vimentin resulted in a significant decrease in viral yield. Acrylamide, which causes disruption of vimentin filaments, also inhibited viral yield. Alanine scanning mutagenesis was used to map the specific amino acid residues in 2C critical for vimentin binding. Using reverse genetics, we identified 2C residues that are necessary for virus growth, suggesting that the interaction between FMDV 2C and cellular vimentin is essential for virus replication.

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confidence: 99%

Foot-and-Mouth Disease Virus Modulates Cellular Vimentin for Virus Survival

Gladue

O’Donnell

Baker-Branstetter

et al. 2013

“…However, in contrast to MNV-1, these viruses were observed to stimulate increased tubulin acetylation. Conversely, other viruses, such as poliovirus and foot-and-mouth disease virus, have been shown to disrupt microtubule formation via cleavage of cytoskeletal components which stabilize microtubules (3,23,24). Why the recruitment of acetylated tubulin to the RC would contribute to MNV-1 replication still remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Mouse Norovirus 1 Utilizes the Cytoskeleton Network To Establish Localization of the Replication Complex Proximal to the Microtubule Organizing Center

Hyde

Gillespie

Mackenzie

2012

Human noroviruses (family Caliciviridae) are the leading cause of nonbacterial gastroenteritis worldwide. Although Human noroviruses are significant enteric pathogens, there exists no reliable vaccine or therapy to treat infected individuals. To date, attempts to cultivate Human noroviruses within the laboratory have met with little success; however, the related murine norovirus mouse norovirus 1 (MNV-1) has provided an ideal model system to study norovirus replication due to the ease with which the virus is cultivated and the ability to infect a small animal model with this virus. Previously we have identified the association between MNV-1 and components of the host secretory pathway and proposed a role for the viral open reading frame 1 proteins in the replication cycle. Here we describe for the first time a role for cytoskeletal components in early MNV-1 replication events. We show that the MNV-1 utilizes microtubules to position the replication complex adjacent to the microtubule organizing center. Chemical disruption of the microtubule network disperses the sites of MNV-1 replication throughout the cell and impairs production of viral protein and infectious virus. Furthermore, we demonstrate the ability of MNV-1 to redistribute acetylated tubulin to the replication complex and that this association is potentially mediated via the MNV-1 major structural protein, VP1. Transient expression of MNV-1 VP1 exhibited extensive colocalization with both ␣-tubulin and acetylated tubulin and was observed to alter the distribution of acetylated tubulin in transfected cells. This study highlights the role of the cytoskeleton in early virus replication events and demonstrates the importance of this interaction in establishing the intracellular location of MNV-1 replication complexes.

“…During replication, FMDV forms a replication complex produced by the rearrangement of intracellular membranes into vesicular structures containing viral nonstructural proteins (2,31). Many other positive-strand RNA viruses also initiate production of replication complexes upon infection of a cell (3,4,11,38,39).…”

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confidence: 99%

Foot-and-Mouth Disease Virus Nonstructural Protein 2C Interacts with Beclin1, Modulating Virus Replication

Gladue

O’Donnell

Baker-Branstetter

et al. 2012

Foot-and-mouth disease virus (FMDV), the causative agent of foot-and-mouth disease, is an Apthovirus within the Picornaviridae family. Replication of the virus occurs in association with replication complexes that are formed by host cell membrane rearrangements. The largest viral protein in the replication complex, 2C, is thought to have multiple roles during virus replication. However, studies examining the function of FMDV 2C have been rather limited. To better understand the role of 2C in the process of virus replication, we used a yeast two-hybrid approach to identify host proteins that interact with 2C. We report here that cellular Beclin1 is a specific host binding partner for 2C. Beclin1 is a regulator of the autophagy pathway, a metabolic pathway required for efficient FMDV replication. The 2C-Beclin1 interaction was further confirmed by coimmunoprecipitation and confocal microscopy to actually occur in FMDV-infected cells. Overexpression of either Beclin1 or Bcl-2, another important autophagy factor, strongly affects virus yield in cell culture. The fusion of lysosomes to autophagosomes containing viral proteins is not seen during FMDV infection, a process that is stimulated by Beclin1; however, in FMDV-infected cells overexpressing Beclin1 this fusion occurs, suggesting that 2C would bind to Beclin1 to prevent the fusion of lysosomes to autophagosomes, allowing for virus survival. Using reverse genetics, we demonstrate here that modifications to the amino acids in 2C that are critical for interaction with Beclin1 are also critical for virus growth. These results suggest that interaction between FMDV 2C and host protein Beclin1 could be essential for virus replication.F oot-and-mouth disease virus (FMDV), a single-stranded positive-sense RNA virus, is the causative agent of foot-andmouth disease (FMD), a highly contagious viral disease of domestic and wild cloven-hoofed animals. Seven serotypes of FMDV exist (A, O, C, Asia, SAT1, SAT2, and SAT3), and recovery from one serotype does not provide immunity against the others (7,22). The infectious virion is a nonenveloped icosahedron composed of four structural proteins: VP1, VP2, VP3, and VP4. The genome of approximately 8,400 nucleotides has a single open reading frame (ORF) that is translated into a polyprotein, which is processed by the three viral proteases Lpro, 2A, and 3C into the polypeptide products P1 (VP1 to VP4), P2 (2A, 2B, and 2C), and P3 (3A, 3B, 3Cpro, and 3Dpol). Further cleavage of these regions yields 14 mature virus proteins, along with several protein intermediates, that are needed for viral replication (18,19).During replication, FMDV forms a replication complex produced by the rearrangement of intracellular membranes into vesicular structures containing viral nonstructural proteins (2, 31). Many other positive-strand RNA viruses also initiate production of replication complexes upon infection of a cell (3,4,11,38,39). FMDV 2C, a 318-amino-acid protein, is the largest membranebinding component of the virus RNA replication complex (30)....