The topology of the phylogenetic tree indicated that there was no remarkable similarity between A/Iran87 and all other isolates in the 3Dpolcoding region

The topology of the phylogenetic tree indicated that there was no remarkable similarity between A/Iran87 and all other isolates in the 3Dpolcoding region. suspension cell cultures. Since this strain has been used as a vaccine strain, it may be inferred that the RGD deletion has no critical role in virus attachment to the cell during the initiation of infection. It is probable that this FMDV subtype can utilize other pathways for cell attachment. Keywords:3Dpolprotein, deletion, RGD, VP1 protein == Introduction == Foot and mouth disease (FMD) is an economically important disease of cloven-hoofed livestock such as cattle, sheep, and other domestic animals in addition to several wild-life species. The causative agent of the FMD is the foot and mouth disease virus (FMDV) [9,11,18]. The disease is considered one of the most important barriers to the worldwide trade of livestock and animal products [12]. FMDV isolates sampled (R)-P7C3-Ome from the world have been categorized into seven different serotypes, A, O, C, Asia1, and South African Territories 1 (SAT1), SAT2, and SAT3, according to antigenic levels; and a large number of variants have appeared within each serotype. Out of the three serotypes (O, A, and Asia1) found to be prevalent in Iran in recent years, serotype A has been found to be more antigenically and genetically diverse than the others [6,10,14]. The FMDV possesses a single-stranded RNA molecule consisting of about 8,200 nucleotides within an icosahedral capsid composed of structural proteins [12]. The open reading frame encodes a single polyprotein which can be cleaved into four structural proteins (VP4, VP2, VP3, and VP1) and eight non-structural proteins (L, 2A, 2B, 2C, 3A, 3B, 3C, and 3D polymerase [3Dpol]). In general, structural proteins are more variable than non-structural proteins. Mutations or deletions in (R)-P7C3-Ome structural proteins may help the FMDV to evade immune responses of the host whereas mutations or deletions in non-structural proteins can inhibit viral replication and protein processing [5]. The FMDV usually infects cells by binding to integrin receptors via a long flexible loop (G-H loop) of VP1 (1D). The sequence of this loop contains a conserved arginineglycine-aspartic acid (RGD) tripeptide motif which is characteristic of ligands that bind to integrin receptors [16]. The VP1 protein is encoded by the VP1 coding region of viral RNA; this coding region is 627~639 bp long and produces a protein containing 209~213 amino acid (R)-P7C3-Ome residues depending on the serotype [6]. The 3Dpolgene sequence is 1,410 nucleotides in length. This gene contains a TAA stop codon and is responsible for encoding a protein containing 470 amino acid residues [4]. Similar to other picornaviruses, the FMDV 3Dpolprotein is a viral-encoded RNA polymerase. Among the different FMDV serotypes and subtypes, both the nucleotide and amino acid sequences of 3Dpolare highly conserved [14]. Uninterrupted co-circulation of the virus in the environment and the absence of viral polymerase proofreading activity during the replication process lead to the appearance of various genetic isolates [2]. Analysis of the viral genome sequence is a crucially important approach for monitoring field isolates in areas where the disease is endemic. Previous studies have shown that Iran has one of the highest reported rates of FMD cases per year [17]. In Iran, FMD is largely controlled by vaccinating cattle and sheep with vaccines prepared against isolates that are likely to be encountered in the region. Spread of the disease is promoted by the presence of large populations of susceptible animals, low vaccination rates, prevalence of multiple serotypes (including serotypes A, Asia1, and O), and unlimited movement of susceptible Rabbit Polyclonal to NM23 animals in the country. Furthermore, there is endemic co-circulation of multiple genotypes of type A virus [19]. The high incidence of FMD has allowed the identification of new variants of the virus over the last 7 years [17]. The general objective of.