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

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, 50-52). 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, 25-28, 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 H...

Structure of deformed wing virus, a major honey bee pathogen

“…S2 C and D). Integrins serve as cell entry receptors for numerous viruses, including the foot and mouth disease virus and several parechoviruses (19)(20)(21). However, the RGD motif is not present in DWV and other iflaviruses.…”

Evolution and conservation in human parechovirus genomes

“…both close to the VP1/2A boundary. It is potentially significant that recombination can occur within the VP1 protein itself, particularly as the RGD motif, which plays a role in receptor binding (Boonyakiat et al, 2001), is located close to the VP1 C terminus and downstream of the putative HPeV4 recombination point. Differences in this region generated through recombination could potentially alter the integrin recognized and thus HPeV biology.…”

Novel Human Parechovirus from Brazil

“…This motif has proven important for HPeV type 1 infectivity, presumably because of interaction with cellular receptors (14). Such a motif is present in all known HPeV strains except type 3, and some researchers have suggested that the latter may use a different receptor for cell entry (3,13).…”