Effects of two amino acid substitutions in the capsid proteins on the interaction of two cell-adapted PanAsia-1 strains of foot-and-mouth disease virus serotype O with heparan sulfate receptor

Abstract

BackgroundSome cell-adapted strains of foot-and-mouth disease virus (FMDV) can utilize heparan sulfate (HS) as a receptor to facilitate viral infection in cultured cells. A number of independent sites on the capsid that might be involved in FMDV-HS interaction have been studied. However, the previously reported residues do not adequately explain HS-dependent infection of two cell-adapted PanAsia-1 strains (O/Tibet/CHA/6/99tc and O/Fujian/CHA/9/99tc) of FMDV serotype O.To identify the molecular determinant(s) for the interaction of O/Tibet/CHA/6/99tc and O/Fujian/CHA/9/99tc with HS receptor, several chimeric viruses and site-directed mutants were generated by using an infectious cDNA of a non-HS-utilizing rescued virus (Cathay topotype) as the genomic backbone. Phenotypic properties of these viruses were determined by plaque assays and virus adsorption and penetration assays in cultured cells.ResultsOnly two of the rescued viruses encoding VP0 of O/Tibet/CHA/6/99tc or VP1 of O/Fujian/CHA/9/99tc formed plaques on wild-type Chinese hamster ovary (WT-CHO; HS+) cells, but not on HS-negative pgsD-677 cells. The formation of plaques by these two chimeric viruses on WT-CHO cells could be abolished by the introduction of single amino acid mutations Gln-2080 → Leu in VP2 of O/Tibet/CHA/6/99tc and Lys-1083 → Glu in VP1 of O/Fujian/CHA/9/99tc, respectively. Nonetheless, the introduced mutation Leu-2080 → Gln in VP2 of O/Fujian/CHA/9/99tc for the construction of expectant recombinant plasmid led to non-infectious progeny virus in baby hamster kidney 21 (BHK-21) cells, and the site-directed mutant encoding Glu-1083 → Lys in VP1 of O/Tibet/CHA/6/99tc did not acquire the ability to produce plaques on WT-CHO cells.Significant differences in the inhibition of the infectivity of four HS-utilizing viruses by heparin and RGD-containing peptide were observed in BHK-21 cells.Interestingly, the chimeric virus encoding VP0 of O/Fujian/CHA/9/99tc, and the site-directed mutant encoding Gln-2080 → Leu in VP2 of O/Tibet/CHA/6/99tc could bind to HS, but there was no expression of the 3A protein of these two viruses in WT-CHO cells.ConclusionThe results suggest that the cooperation of certain specific amino acid residues in the capsid proteins of these two cell-adapted PanAsia-1 strains is essential for viral infectivity, the heparin affinity and the capability on FMDV-HS interaction.

Model of persistent foot‐and‐mouth disease virus infection in multilayered cells derived from bovine dorsal soft palate

“…Accordingly, whereas integrin α V β 6 was expressed by subsets of DSP cells after isolation, and these cells were susceptible to FMDV‐mediated lysis, integrin α V β 6 expression could not be detected in the multilayers that were more resistant. Nevertheless, the multilayer cells were also infected, maybe through integrins α V β 1 , α V β 3 , α V β 6 , α V β 8 (O'Donnell et al, ; Wang, Wang, Shang, Zhang, & Liu, ), heparane sulphate (Bai et al, ; Jackson et al, ), or other proteins that have not yet been characterized (Baranowski et al, ). Our model probably mirror what happens naturally but since the virus had been passed in cell culture, it cannot be excluded that the receptor use had changed compared to that of the parental strain (Baranowski et al, ; O'Donnell et al, ).…”

Cell culture propagation of foot-and-mouth disease virus: adaptive amino acid substitutions in structural proteins and their functional implications

“…While unique amino acid substitutions have been described for different FMDV serotypes (see Table 2), there are parts of the protein where amino acid variations accumulate. Several amino acid exchanges are described for residues 78-80 and 130-131 for serotypes A and O [15,50,51,54,58,63,70,71] as well as at position 77 for SAT2 [50]. While the residues 78-80 follow the BC loop at position 70-76, the residues 130-131 are part of the EF loop (position 130-137) [48].…”

“…The protein is shown in its original orientation within a protomer (a) and in a rotated position to show the surfaceexposed loops of the protein that are highlighted in orange (b). The protein map is constructed from FMDV serotype O (PDB: 1FOD) [49] using the UCSF Chimera package [76] of VP1 by changing its spatial orientation, allowing the virus to either use HS or an unknown receptor for attachment to host cells [54,58,63,70]. Furthermore, changes in this part of VP2 are often described to occur in combination with substitutions in VP1 [58,63] during passaging in BHK cells [15,71].…”

“…Furthermore, changes in this part of VP2 are often described to occur in combination with substitutions in VP1 [58,63] during passaging in BHK cells [15,71]. Another well-described phenomenon for serotype A and O are amino acid exchanges at positions 133, 134, and 136 [13,15,51,54,57,72]. This region lies within the αB helix of VP2 (residues 133-138) and is part of the depression that is used for HS binding [48].…”

Single Amino Acid Substitutions Surrounding the Icosahedral Fivefold Symmetry Axis Are Critical for Alternative Receptor Usage of Foot-and-Mouth Disease Virus

“…For our initial study, we were concerned that a genetically engineered virus of Cathay topotype of FMDV serotype O (rHN) with a high affinity for heparin was insufficient to initiate an integrin-independent entry into HS-positive CHO-K1 cells and mutant pgsD-677 cells [ 31 , 32 ]. It was subsequently found that the phenotypic properties of its wild-type (wt) and tissue culture (tc) parental viruses (O/HN/CHA/93wt and O/HN/CHA/93tc) should be distinct from that of rHN in BHK-21 cells and these two integrin-negative CHO cell lines.…”