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Journal of Virology logoLink to Journal of Virology
. 2001 Oct;75(20):10000–10004. doi: 10.1128/JVI.75.20.10000-10004.2001

Arginine-Glycine-Aspartic Acid Motif Is Critical for Human Parechovirus 1 Entry

Yingmanee Boonyakiat 1,, Pamela J Hughes 1, Farideh Ghazi 1,, Glyn Stanway 1,*
PMCID: PMC114574  PMID: 11559835

Abstract

The human parechovirus 1 RGD motif in VP1 was studied by mutagenesis. An RGD-to-RGE change gave only revertant viruses with a restored RGD, while deletion of GD was lethal and nonrevertable. Mutations at the +1 and +2 positions had some effect on growth properties and a +1 M-to-P change was lethal. These studies indicate that the RGD motif plays a critical role in infectivity, presumably by interacting with integrins, and that downstream amino acids can have an influence on function.


Human parechovirus 1 (HPeV1) is a common pathogen that usually causes mild disease, typically in children (21, 43, 44). It belongs to the human parechovirus species of the recently recognized Parechovirus genus of Picornaviridae (24). Picornaviruses have a single-stranded RNA genome of positive polarity, 7,100 to 8,500 nucleotides long and surrounded by an icosahedral capsid usually consisting of four structural proteins, VP1 to VP4 (41). However, in HPeV1 the maturation cleavage of VP0 to VP2 and VP4 appears not to occur (16, 42). A characteristic form of the 2A protein is among other distinctive features of this genus (14, 39).

Several types of molecules, including integrins, immunoglobulin superfamily members, and complement regulatory proteins, have been recruited as picornavirus receptors (7). These molecules interact with structures on the virus surface, particularly the canyon, but in most cases the precise details of these interactions are not known. Sequence analysis of HPeV1 indicated a possible determinant of virus-host cell interaction, since the VP1 C terminus contains an arginine-glycine-aspartic acid motif (RGD) (16, 22, 42). This also occurs in the closely related parechovirus, HPeV2 (12, 33). RGD motifs are known to participate in cell-cell and cell-matrix interactions and to play a role in host cell recognition by several viruses through interactions with cell surface integrins (15, 38). The picornaviruses coxsackievirus A9 (CAV9) and echovirus 9 (EV9) also contain RGD motifs, located in precisely the same position in VP1 as that in HPeV1 (4, 5, 40, 5052). Another picornavirus, foot-and-mouth-disease virus (FMDV), contains an RGD motif, but it is in the prominent VP1 G-H loop (6, 8, 45, 46). Biochemical and genetic approaches have established a role for the RGD motif in FMDV, CAV9, and EV9 internalization (3, 9, 13, 2528, 32, 35, 36, 52). In the latter two viruses, this role is not critical for infectivity in cultured cells, as viable RGD-less mutants exist (13, 50).

In order to investigate the significance of the RGD motif in HPeV1 replication, several mutations were introduced within and downstream of this sequence. This was achieved by producing a cassette vector, pHPeV-YB, from the complete cDNA clone pHPeV1 (29). This allowed any of the amino acids GDMANL (HPeV1 nucleotide positions 3002 to 3017) to be changed by ligating annealed pairs of oligonucleotides, giving the appropriate sticky ends, into pHPeV-YB cut with SacII/BsmI. Linear cDNA templates were prepared by digestion at a MluI site immediately downstream of the HPeV1 poly(A) tract. cRNAs obtained by transcription were transfected into tissue culture cells (green monkey kidney [GMK], A549 [human lung carcinoma], and human rhabdomyosarcoma [RD] cells) by using Lipofectin as previously described (13). Transfected cells were incubated at 37°C for 17 h and overlaid with 0.5% carboxymethyl cellulose–0.5% agarose in culture medium. Individual virus plaques were picked 3 days after the transfection and were propagated once. When a cytopathic effect was seen, infected cells were freeze-thawed twice to release viruses. Infected cell lysates were kept as stock viruses at −70°C. Plaque titrations were performed in duplicate by adsorbing virus for 1 h to confluent cell monolayers and then overlaying with carboxymethyl cellulose-agarose. After 2 to 3 days of incubation, viral plaques were visualized by staining with 0.1% crystal violet in 1% ethanol.

Table 1 shows the sequences of the oligonucleotides used to construct mutants, the mutations introduced, and their effects. The names of the mutant cDNAs reflect the virus protein and specific amino acid position mutated (e.g., pD1224E is a D [aspartic acid]-to-E [glutamic acid] change in VP1 at position 224). The presence of the mutations in viruses recovered from transfections was confirmed by reverse transcription-PCR and sequencing across the RGD region (11).

TABLE 1.

Oligonucleotides used to produce mutant HPeV1 cDNA and the phenotypes of viruses recovered

pHPeV1 cDNA Oligonucleotides used to produce mutant cDNAsa Amino acid sequence encodedb Effect of mutation
Wild type (WT) 5′   GGTGATATGGCCAACC 3′ RGDMAN WT properties
3′ CGCCACTATACCGGTT   5′
pD1224E* 5′   GGAGAAATGGCCAACC 3′ RGEMAN Lethalc
3′ CGCCTCTTTACCGGTT   5′
pΔGD 5′   ATGGCCAACC       3′ R--MAN Lethal
3′ CGTACCGGTT         5′
pM1225L/R 5′   GGTGACCNCGCAAACC 3′ RGDLAN Viable (WT properties)
3′ CGCCACTGGNGCGTTT   5′ RGDRAN Viable (WT properties)
pM1225H 5′   GGTGACCATGCTAACC 3′ RGDHAN Viable (small plaque)
3′ CGCCACTGGTACGATT   5′
pM1225P 5′   GGTGACCCAGCCAACC 3′ RGDPAN Lethald
3′ CGCCACTGGGTCGGTT   5′
pA1226S/C/Y 5′   GGTGACATGTNTAACC 3′ RGDMSN Viable (WT properties)
3′ CGCCACTGTACANATT   5′ RGDMCN Viable (small plaque)
RGDMYN Viable (small plaque)
a

When annealed, the oligonucleotides give the overhangs shown, which are compatible to those generated by SacII and BsmI, sites for which are located in the pHPeV-YB cassette vector. Mutated codons are marked by bold type. 

b

Mutated amino acids are marked by bold type. 

c

Only revertant viruses (E→D) were obtained. 

d

Only pseudorevertant viruses (P→L) were obtained. 

The structurally conservative change of RGD→RGE (clone pD1224E*) was initially introduced, as RGE is known not to function in integrin binding (38). A cDNA clone derived from pHPeV-YB but containing the wild-type sequence (pD1224D) was also produced. RNA from pD1224D gave plaques (3 × 104 plaques/μg of RNA) 3 days after transfection, which is typical of wild-type HPeV1. Following transfection of pD1224E*, a small number of plaques (5 plaques/μg of RNA) were obtained after 3 days. Several of the viruses were propagated and then sequenced in the RGD region. All the sequences showed the presence of an aspartic acid (D) codon (GAU), representing a reversion from the original glutamic acid (E) codon (GAA) (Table 2). These were genuine revertants, as all exhibited a unique, silent mutation introduced into the preceding glycine codon (G1223) of pD1224E*. This indicates that HPeV1 carrying an RGE sequence is not viable, but that reversion to RGD gives a virus with wild-type growth properties. All revertant viruses contained the same codon (GAU) for aspartic acid, possibly reflecting the codon preference of HPeV1, as most codons end in A or U in the genome of this virus (12).

TABLE 2.

Comparison of revertant virus sequences obtained from pD1224E* with those from parental cDNA, pD1224D (pseudo-wild type), and wild type (HPeV1 wt)

Virus or cDNA Nucleotide and amino acid sequencesa
HPeV1 wtb   R     G     D     M     A  
C G G G G U G A U A U G G C A
pD1224D   R     G     D     M     A  
C G C G G T G A T A T G G C C
pD1224E*   R     G     E     M     A  
C G C G G A G A A A T G G C C
Revertants from pD1224E*   R     G     D     M     A  
C G C G G A G A U A U G G C C
a

Nucleotides different from the wild-type cDNA are shown in bold. The silent nucleotide change used to confirm that the revertant viruses were obtained from pD1224E* is underlined. 

b

wt, wild type. 

To further analyze the RGD motif, a GD deletion was introduced into cDNA. RNA transfected from this cDNA clone (pΔGD) was not infectious and no virus was recovered from the liquid overlay, even after multiple blind passages. Thus, deletion of the GD dipeptide of the RGD motif is a lethal, nonrevertable mutation. As RGD-less CAV9 mutants show no growth impairment on RD cells (13), transfections of pD1224E and pΔGD RNA were also performed using these cells. However, in neither case was an RGD-less HPeV1 recovered. Similarly, these constructs did not yield viable viruses in A549 cells. These results indicate that in GMK, RD, and A549 cells, a functional RGD is required for HPeV1 replication. This contrasts with the ability to produce viable CAV9 RGE or RGD deletion mutants (13) and the lack of an RGD motif in the nonpathogenic EV9 strain Hill (50). However, in FMDV A12, mutation of RGD is lethal and it has been shown that RGD-deleted viruses are unable to bind to cells (26, 28).

The critical requirement for an RGD motif can be circumvented in some FMDV strains. Viable virus particles were produced after changing the RGD to RGE in FMDV strain O1K (25). It is therefore probable that FMDV O1K can use more than one receptor and/or that other regions, in addition to RGD, may be responsible for cell binding. One study showed that an FMDV O1K strain binds to heparan sulfate on the cell surface, enabling efficient infection (18). High-efficiency binding is due to a mutation (histidine to arginine) at residue 56 in VP3, selected by adaptation to tissue culture cells (10). FMDV mutants lacking both an RGD motif and heparan sulfate binding ability have been isolated, suggesting that there is at least one more potential receptor-antireceptor interaction open to this virus (1). Possible HPeV1 interactions with heparan sulfate were investigated by using heparin-Sepharose. HPeV1 was incubated with heparin-Sepharose and the amount of unbound virus was determined by plaque titration assay and compared to that of cells treated with the control (Sepharose). This experiment indicated there was no HPeV1 binding to heparin (data not shown), making it unlikely that heparan sulfate plays a role in HPeV1 infection. HPeV1 infection is also not blocked by heparin (data not shown). Furthermore, multiple blind passage of GD-deleted HPeV1 did not give a virus able to infect by an alternative route.

Another molecule implicated in entry of RGD-containing picornaviruses is β2 microglobulin, as infection with CAV9 and EV9 is blocked by antibodies to this protein by interference with a postbinding step (48, 49). However, an antibody which efficiently blocked CAV9 infection of RD cells had no effect on HPeV1 infection of the same cells (data not shown). Similarly, the failure of an antibody to β2 microglobulin to block HPeV1 infection of A549 cells has been reported (23). Thus, if molecules other than αv-containing integrins are involved in the binding or internalization of HPeV1, they probably do not include heparan sulfate or β2 microglobulin.

There are some similarities in the amino acids which tend to occur downstream of the RGD motif in FMDVs, CAV9, and EV9 (5, 17, 40), and the consensus sequence RGD(M/L)XXL can be derived (Fig. 1). HPeV1 (and to a lesser extent HPeV2) conforms to this consensus (12, 22, 33, 42). A +1 L is found in two completely sequenced HPeV2 strains and in a wild-type HPeV1 strain, while M is found in three wild-type HPeV1 strains (12, 22, 33). In the majority of more than 30 wild-type CAV9 isolates, together with most FMDV strains and EV9, L is present (4, 5, 40, 51). In FMDV, some SAT-2 strains show arginine (R) at position +1 (2). The +2 position (RGDMA, [A1226]) is one of the few RGD-flanking amino acids conserved between HPeV1 and HPeV2 (12). Alanine at position +2 was also found in many of the viruses compared (Fig. 1).

FIG. 1.

FIG. 1

Amino acid sequence comparison of the VP1 C-terminal region of representative strains of HPeV1, HPeV2, and the enteroviruses CAV9 and EV9 (4, 12, 16, 33, 51). The sequences of the RGD-containing G-H loop regions of representatives of each FMDV serotype are also shown (1, 6, 8, 45, 46).

To investigate the significance of this conservation, the mutant cDNAs pM1225L, pM1225R, pM1225H, pM1225P, pA1226S, pA1226C, and pA1226Y were produced. Mutant RNAs (except from pM1225P) were infectious (Table 1), and sequencing revealed retention of the mutation in the progeny virus. However, after changing M1225 to P, no M1225P mutant virus was recovered and only a pseudorevertant virus, containing leucine (L) at position 225 instead of proline (P), was obtained (Table 3). This was a genuine pseudorevertant, as it contained a silent change at the A1226 codon (GCC), introduced only into pM1225P.

TABLE 3.

Comparison of partial sequence of pseudorevertant virus obtained from pM1225P with those of parental cDNA and the wild-type sequence

Virus or cDNA Nucleotide and amino acid sequencea
HPeV1 wtb   R     G     D     M     A  
C G G G G U G A U A U G G C A
pM1225P   R     G     D     P     A  
C G C G G T G A C C C A G C C
Pseudorevertant from pM1225P   R     G     D     L     A  
C G C G G U G A C C U A G C C
a

Nucleotides different from the wild-type cDNA are shown in bold. A unique, silent nucleotide change introduced into pM1225P and used to confirm that pseudorevertant (P→L) viruses were obtained in this construct is underlined. 

b

wt, wild type. 

The plaque size of each mutant virus is shown in Table 4. Plaque sizes of M1225L, M1225R, and A1226S are similar to those of wild-type HPeV1, while a small plaque phenotype was observed for M1225H, A1226Y, and A1226C. This largely, but not entirely, correlates with the titer achieved upon propagation, as M1225L, M1225R, and A1226Y grew to wild-type levels, while M1225H, A1226S, and A1226C achieved a lower titer upon passage (data not shown). The reason for the lack of correlation shown by A1226Y and A1226S is not clear but probably resides in the relatively minor nature of the effect on RGD function and resulting growth defects. Growth curves of the mutants were similar to those of wild-type HPeV1 but appeared to have a slightly delayed time course (data not shown). The results show that none of these mutations (except M1225P) destroy the viability of HPeV1, and so the RGD motif can function with a number of different downstream amino acids. However, the nature of both the +1 and +2 amino acids can have some effect on RGD function as shown, for instance, by the plaque size of mutants and by lethality of the M1225P change. These results are similar to those seen in CAV9, where a position +1 M-to-H change gave a small plaque mutant (13), while an equivalent mutation in FMDV O1K gave a virus incapable of inducing a cytopathic effect (25). Other workers have also reported a significant effect of flanking residues on RGD function (27, 35).

TABLE 4.

Plaque sizes of HPeV1 mutants on GMK cells

Virus Amino acid sequence of recovered viruses Plaque diam (mm)a
HPeV1 wtb RALRGDMANLTK 4.2 ± 1.0
M1225L ------L----- 3.9 ± 0.7
M1225R ------R----- 4.0 ± 1.0
M1225H ------H----- 2.0 ± 0.8
A1226S -------S---- 3.8 ± 0.9
A1226Y -------Y---- 2.8 ± 0.7
A1226C -------C---- 2.2 ± 0.8
a

Mean ± standard deviation. 

b

wt, wild type. 

Extensive work has shown that the RGD motifs of FMDV, CAV9, and EV9 are involved in cell binding and entry. The HPeV1 RGD motif is in a similar sequence context to these functional RGDs and is located in an analogous position to those of CAV9 and EV9. In view of these similarities, the HPeV1 RGD motif may also be involved in the early stages of replication, presumably in cell attachment. Indeed, HPeV1 was demonstrated to compete for cell surface binding with CAV9 (37). Blocking of infectivity with RGD peptides has also been reported (42). Studies using phage display libraries showed that HPeV1 can bind to phage expressing an amino acid sequence found in the integrin β1 subunit (34). Antibody blocking experiments suggested a role for integrins αvβ1 and anti-αvβ3 (34), and recent work supports this conclusion (23, 47). αv integrins are known to bind RGD motifs, and the data suggest that HPeV1 may use its RGD region to recognize one or both of these molecules as cellular receptors. However, the work described here does not exclude a role in other postentry steps or in assembly.

The reason for the conserved pattern of amino acids downstream of the RGD region in diverse picornaviruses is not clear, but these amino acids may influence the efficiency of binding or even the integrin selected. For instance, it has been shown that FMDV isolates with a +1 leucine bind efficiently to integrin α5β1, while a +1 arginine abolishes binding to α5β1 but is part of an efficient ligand for αvβ3 (20). This conservation may therefore be the basis of the common recognition of integrin αvβ3 reported for all of these viruses (23, 3032, 37, 47), although αvβ1, α5β1, and αvβ6 may also be involved (19, 20, 23).

This is the first reported study to evaluate the HPeV1 RGD motif using site-directed mutagenesis. Previous blocking experiments using integrin antibodies and peptides indicated the importance of the RGD region, and so these results are not unexpected (23, 34, 42, 47). However, blocking experiments on CAV9 revealed an important role for its RGD but mutational analysis showed that this role is not absolutely necessary, indicating that there may be alternative pathways (13, 36, 37). Thus, the mutational analysis of HPeV1 is valuable and the results indicate that the RGD motif, although present in a similar sequence context, functions in somewhat different ways in picornaviruses. In HPeV1, as in FMDV, it appears to have a critical role, which can only be circumvented in the case of FMDV under some conditions when heparan sulfate and possibly other molecules can serve as an alternative receptor. In contrast, CAV9 and EV9 can exist in RGD-less forms, and in some cells these mutants grow efficiently (13, 50, 52). Thus, in these viruses it is possible that an RGD-dependent step is a component of one entry pathway among two or more alternatives. However, it should be noted that all CAV9 clinical isolates studied to date possess an RGD motif (5, 40), while the presence of an RGD motif correlates with EV9 pathogenesis in mice (52). In addition, FMDV strains virulent for cattle utilize the RGD-binding integrin αvβ3 as a receptor (30). These observations imply that the RGD motif plays a key role in normal host infections in FMDV, CAV9, EV9, and HPeV1.

Acknowledgments

This work was supported by the Wellcome Trust, by the University of Essex Research Promotion Fund, and by a studentship from the Thai Government awarded to Y.B.

REFERENCES

  • 1.Baranowski E, Ruiz-Jarabo C M, Sevilla N, Andreu D, Beck E, Domingo E. Cell recognition by foot-and-mouth disease virus that lacks the RGD integrin-binding motif: flexibility in aphthovirus receptor usage. J Virol. 2000;74:1641–1647. doi: 10.1128/jvi.74.4.1641-1647.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Bastos A D S. Detection and characterization of foot-and-mouth disease virus in sub-Saharan Africa. Onderstepoort J Vet Res. 1998;65:37–47. [PubMed] [Google Scholar]
  • 3.Berinstein A, Roivainen M, Hovi T, Mason P W, Baxt B. Antibodies to the vitronectin receptor (integrin αvβ3) inhibit binding and infection of foot-and-mouth-disease virus to cultured cells. J Virol. 1995;69:2664–2666. doi: 10.1128/jvi.69.4.2664-2666.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Chang K H, Auvinen P, Hyypiä T, Stanway G. The nucleotide sequence of coxsackievirus A9. Implications for receptor binding and enterovirus classification. J Gen Virol. 1989;70:3269–3280. doi: 10.1099/0022-1317-70-12-3269. [DOI] [PubMed] [Google Scholar]
  • 5.Chang K H, Day C, Walker J, Hyypiä T, Stanway G. The nucleotide sequences of wild-type coxsackievirus A9 strains imply that an RGD motif in VP1 protein is functionally significant. J Gen Virol. 1992;73:621–626. doi: 10.1099/0022-1317-73-3-621. [DOI] [PubMed] [Google Scholar]
  • 6.Escarmis C, Carrillo E, Ferrer M, Garcia Arriaza J, Lopez N, Tami C, Verdaguer N, Domingo E, Franze-Fernandez M. Rapid selection in modified BHK-21 cells of a foot-and-mouth disease virus variant showing alterations in cell tropism. J Virol. 1998;72:10171–10179. doi: 10.1128/jvi.72.12.10171-10179.1998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Evans D J, Almond J W. Cell receptors for picornaviruses as determinants of cell tropism and pathogenesis. Trends Microbiol. 1998;6:198–202. doi: 10.1016/s0966-842x(98)01263-3. [DOI] [PubMed] [Google Scholar]
  • 8.Forss S, Strebel K, Beck E, Schaller H. Nucleotide sequence and genome organization of foot-and-mouth disease virus. Nucleic Acids Res. 1984;12:6587–6601. doi: 10.1093/nar/12.16.6587. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Fox G, Parry N A, Barnett P V, McGinn B, Rowlands D J, Brown F. The cell attachment site on foot-and-mouth disease virus includes the amino acid sequence RGD (arginine-glycine-aspartic acid) J Gen Virol. 1989;70:625–637. doi: 10.1099/0022-1317-70-3-625. [DOI] [PubMed] [Google Scholar]
  • 10.Fry E E, Lea S M, Jackson T, Newman J W I, Ellard F M, Blakemore W E, Abu-Ghazaleh R, Samuel A, King A M Q, Stuart D I. The structure and function of a foot-and-mouth disease virus-oligosaccharide receptor complex. EMBO J. 1999;18:543–554. doi: 10.1093/emboj/18.3.543. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Gama R E, Hughes P J, Bruce C B, Stanway G. Polymerase chain reaction amplification of rhinovirus nucleic acids from clinical materials. Nucleic Acids Res. 1988;16:9346. doi: 10.1093/nar/16.19.9346. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Ghazi F, Hughes P J, Hyypiä T, Stanway G. Molecular analysis of human parechovirus type 2 (formerly echovirus 23) J Gen Virol. 1998;79:2641–2650. doi: 10.1099/0022-1317-79-11-2641. [DOI] [PubMed] [Google Scholar]
  • 13.Hughes P J, Horsnell C, Hyypiä T, Stanway G. The coxsackievirus A9 RGD motif is not essential for virus infectivity. J Virol. 1995;69:8035–8040. doi: 10.1128/jvi.69.12.8035-8040.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Hughes P J, Stanway G. The 2A proteins of three diverse picornaviruses are related to each other and to the H-rev-107 family of proteins involved in the control of cell proliferation. J Gen Virol. 2000;80:201–207. doi: 10.1099/0022-1317-81-1-201. [DOI] [PubMed] [Google Scholar]
  • 15.Hynes R O. Integrins: versatility, modulation, and signaling in cell adhesion. Cell. 1992;69:11–25. doi: 10.1016/0092-8674(92)90115-s. [DOI] [PubMed] [Google Scholar]
  • 16.Hyypiä T, Horsnell C, Maaronen M, Khan M, Kalkkinen N, Auvinen P, Kinnunen L, Stanway G. A distinct picornavirus group identified by sequence analysis. Proc Natl Acad Sci USA. 1992;89:8847–8851. doi: 10.1073/pnas.89.18.8847. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Hyypiä T, Stanway G. Biology of coxsackie A viruses. Adv Virus Res. 1993;42:343–373. doi: 10.1016/s0065-3527(08)60089-5. [DOI] [PubMed] [Google Scholar]
  • 18.Jackson T, Ellard F M, Ghazaleh R A, Brookes S M, Blakemore W E, Corteyn A H, Stuart D I, Newman J W, King A M Q. Efficient infection of cells in culture by type-O foot-and-mouth-disease virus requires binding to cell-surface heparan-sulfate. J Virol. 1996;70:5282–5287. doi: 10.1128/jvi.70.8.5282-5287.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Jackson T, Sheppard D, Denyer M, Blakemore W, King A M Q. The epithelial integrin αvβ6 is a receptor for foot-and-mouth disease virus. J Virol. 2000;74:4949–4956. doi: 10.1128/jvi.74.11.4949-4956.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Jackson T, Blakemore W, Newman J W I, Knowles N J, Mould A P, Humphries M J, King A M Q. Foot-and-mouth disease virus is a ligand for the high-affinity binding conformation of integrin alpha 5 beta 1: influence of the leucine residue within the RGDL motif on selectivity of integrin binding. J Gen Virol. 2000;81:1383–1391. doi: 10.1099/0022-1317-81-5-1383. [DOI] [PubMed] [Google Scholar]
  • 21.Joki-Korpela P, Hyypiä T. Diagnosis and epidemiology of echovirus 22 infections. Clin Infect Dis. 1998;27:129–136. doi: 10.1086/514615. [DOI] [PubMed] [Google Scholar]
  • 22.Joki-Korpela P, Roivainen M, Lankinen H, Pöyry T, Hyypiä T. Antigenic properties of human parechovirus 1. J Gen Virol. 2000;81:1709–1718. doi: 10.1099/0022-1317-81-7-1709. [DOI] [PubMed] [Google Scholar]
  • 23.Joki-Korpela P, Marjomaki V, Krogerus C, Heino J, Hyypiä T. Entry of human parechovirus 1. J Virol. 2001;75:1958–1967. doi: 10.1128/JVI.75.4.1958-1967.2001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.King A M Q, Brown F, Christian P, Hovi T, Hyypiä T, Knowles N J, Lemon S M, Minor P D, Palmenberg A C, Skern T, Stanway G. Picornaviridae. In: Van Regenmortel M H V, Fauquet C M, Bishop D H L, Calisher C H, Carsten E B, Estes M K, Lemon S M, Maniloff J, Mayo M A, McGeoch D J, Pringle C R, Wickner R B, editors. Virus taxonomy. Seventh report of the International Committee for the Taxonomy of Viruses. New York, N.Y: Academic Press; 2000. pp. 657–673. [Google Scholar]
  • 25.Leippert M, Beck E, Weiland F, Pfaff E. Point mutations within the βG-βH loop of foot-and mouth disease virus O1K affect virus attachment to target cells. J Virol. 1997;71:1046–1051. doi: 10.1128/jvi.71.2.1046-1051.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Mason P W, Rieder E, Baxt B. RGD sequence of foot-and-mouth disease virus is essential for infecting cells via the natural receptor but can be bypassed by an antibody-dependent enhancement pathway. Proc Natl Acad Sci USA. 1994;91:1932–1936. doi: 10.1073/pnas.91.5.1932. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Mateu M G, Valero M L, Andreu D, Domingo E. Systematic replacement of amino acid residues within an Arg-Gly-Asp-containing loop of foot-and-mouth disease virus and effect on cell recognition. J Biol Chem. 1996;271:12814–12819. doi: 10.1074/jbc.271.22.12814. [DOI] [PubMed] [Google Scholar]
  • 28.McKenna T S C, Lubroth J, Rieder E, Baxt B, Mason P W. Receptor binding site-deleted foot-and-mouth disease (FMD) virus protects cattle from FMDV. J Virol. 1995;69:5787–5790. doi: 10.1128/jvi.69.9.5787-5790.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Nateri A S, Hughes P J, Stanway G. In vivo and in vitro identification of structural and sequence elements of the human parechovirus 5′ untranslated region required for internal initiation. J Virol. 2000;74:6269–6277. doi: 10.1128/jvi.74.14.6269-6277.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Neff S, Sa-Carvalho D, Rieder E, Mason P W, Blystone S D, Brown E J, Baxt B. Foot-and-mouth disease virus virulent for cattle utilizes the integrin αVβ3 as its receptor. J Virol. 1998;72:3587–3594. doi: 10.1128/jvi.72.5.3587-3594.1998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Neff S, Mason P W, Baxt B. High-efficiency utilization of the bovine integrin αvβ3 as a receptor for foot-and-mouth disease virus is dependent on the bovine beta3 subunit. J Virol. 2000;74:7298–7306. doi: 10.1128/jvi.74.16.7298-7306.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Nelsen-Salz B, Eggers H J, Zimmermann H. Integrin αvβ3 (vitronectin receptor) is a candidate receptor for the virulent echovirus 9 strain Barty. J Gen Virol. 1999;80:2311–2313. doi: 10.1099/0022-1317-80-9-2311. [DOI] [PubMed] [Google Scholar]
  • 33.Oberste M S, Maher K, Pallansch M A. Complete sequence of echovirus 23 and its relationship to echovirus 22 and other human enteroviruses. Virus Res. 1998;56:217–223. doi: 10.1016/s0168-1702(98)00080-x. [DOI] [PubMed] [Google Scholar]
  • 34.Pulli T, Koivunen E, Hyypiä T. Cell-surface interactions of echovirus 22. J Biol Chem. 1997;272:21176–21180. doi: 10.1074/jbc.272.34.21176. [DOI] [PubMed] [Google Scholar]
  • 35.Rieder E, Baxt B, Mason P W. Animal-derived antigenic variants of foot-and-mouth-disease virus type A12 have low affinity for cells in culture. J Virol. 1994;68:5296–5299. doi: 10.1128/jvi.68.8.5296-5299.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Roivainen M, Hyypiä T, Piirainen L, Kalkkinen N, Stanway G, Hovi T. RGD-dependent entry of coxsackievirus A9 to host cells and its bypass after cleavage of VP1 by intestinal proteases. J Virol. 1991;65:4735–4740. doi: 10.1128/jvi.65.9.4735-4740.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Roivainen M, Piirainen L, Hovi T, Riikonen T, Heino J, Hyypiä T. Entry of coxsackievirus A9 into host cells: specific interactions with αvβ3 integrin, the vitronectin receptor. Virology. 1994;203:357–365. doi: 10.1006/viro.1994.1494. [DOI] [PubMed] [Google Scholar]
  • 38.Ruoslahti E, Pierschbacher M D. New perspectives in cell adhesion: RGD and integrins. Science. 1987;238:491–493. doi: 10.1126/science.2821619. [DOI] [PubMed] [Google Scholar]
  • 39.Ryan M D, Flint M. Virus-encoded proteinases of the picornavirus super-group. J Gen Virol. 1997;78:699–723. doi: 10.1099/0022-1317-78-4-699. [DOI] [PubMed] [Google Scholar]
  • 40.Santti J, Harvala H, Kinnunen L, Hyypiä T. Molecular epidemiology and evolution of coxsackievirus A9. J Gen Virol. 2000;81:1361–1372. doi: 10.1099/0022-1317-81-5-1361. [DOI] [PubMed] [Google Scholar]
  • 41.Stanway G. Structure, function and evolution of picornaviruses. J Gen Virol. 1990;71:2483–2501. doi: 10.1099/0022-1317-71-11-2483. [DOI] [PubMed] [Google Scholar]
  • 42.Stanway G, Kalkkinen N, Roivainen M, Ghazi F, Khan M, Smyth M, Meurman O, Hyypiä T. Molecular and biological characteristics of echovirus 22. A representative of a new picornavirus group. J Virol. 1994;68:8232–8238. doi: 10.1128/jvi.68.12.8232-8238.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Stanway G, Joki-Korpela P, Hyypiä T. Human parechoviruses—biology and clinical significance. Rev Med Virol. 2000;10:57–69. doi: 10.1002/(sici)1099-1654(200001/02)10:1<57::aid-rmv266>3.0.co;2-h. [DOI] [PubMed] [Google Scholar]
  • 44.Stanway G, Hyypiä T. Parechoviruses. J Virol. 1999;73:5249–5254. doi: 10.1128/jvi.73.7.5249-5254.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Stram Y, Laor O, Molad T, Chai D, Moore D, Yadin H, Becker Y. Nucleotide sequence of the P1 region of serotype Asia1 foot-and-mouth disease virus. Virus Genes. 1994;8:275–278. doi: 10.1007/BF01704521. [DOI] [PubMed] [Google Scholar]
  • 46.Tosh C, Venkataramanan R, Hemadri D, Sanyal A, Samuel A R, Knowles N J, Kitching R P. Nucleotide sequence of the structural protein-encoding region of foot-and-mouth disease virus A22-India. Virus Genes. 2000;20:269–275. doi: 10.1023/a:1008152914655. [DOI] [PubMed] [Google Scholar]
  • 47.Triantafilou K, Triantafilou M, Wilson K M, Takada Y, Fernandez N. Human parechovirus 1 utilizes integrins αvβ3 and αvβ1 as receptors. J Virol. 2000;74:5856–5862. doi: 10.1128/jvi.74.13.5856-5862.2000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 48.Triantafilou M, Triantafilou K, Wilson K M, Takada Y, Fernandez N, Stanway G. Involvement of β2-microglobulin and integrin αvβ3 molecules in the coxsackievirus A9 infectious cycle. J Gen Virol. 1999;80:2591–2600. doi: 10.1099/0022-1317-80-10-2591. [DOI] [PubMed] [Google Scholar]
  • 49.Ward T, Powell R M, Pipkin P A, Evans D J, Minor P D, Almond J W. Role for β2-microglobulin in echovirus infection of rhabdomyosarcoma cells. J Virol. 1998;72:5360–5365. doi: 10.1128/jvi.72.7.5360-5365.1998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 50.Zimmermann H, Eggers H J, Kraus W, Nelsen-Salz B. Complete nucleotides sequence and biological properties of an infectious clone of prototype echovirus 9. Virus Res. 1995;39:311–319. doi: 10.1016/0168-1702(95)00078-x. [DOI] [PubMed] [Google Scholar]
  • 51.Zimmermann H, Eggers H J, Nelsen-Salz B. Molecular cloning and sequence determination of the complete genome of the virulent echovirus 9 strain Barty. Virus Genes. 1996;12:149–154. doi: 10.1007/BF00572953. [DOI] [PubMed] [Google Scholar]
  • 52.Zimmermann H, Eggers H J, Nelsen-Salz B. Cell attachment and mouse virulence of echovirus 9 correlate with an RGD motif in the capsid protein VP1. Virology. 1997;233:149–156. doi: 10.1006/viro.1997.8601. [DOI] [PubMed] [Google Scholar]

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