The genome of FMDV is about 8.5 Kb in length enclosed within a protein capsid. It has four major parts: 5 Untranslated region (5 UTR), Coding region, 3 Untranslated region (3 UTR), and a poly "A" tail. The 5 UTR is linked with Vpg (3B) which serves as primer in replication. 5 UTR contains an S fragment at its 5 end which encompasses 360 bases, folds into long stem loop and plays a role in genome stability and the binding of protein involved in genome replication [50] . Following S fragment there is poly "C" tract comprising over 90% "C" residues. The length of this tract is extremely variable [51] . There are some evidences that length of this tract is associated with virulence and hence persistence [52] . After poly "C" tract, there is a series of RNA pseudo knot structures of unknown function [53] . Downstream to the pseudo knot there is cisacting replicative element (cre) [54] . The cre has conserved AAA sequences and is essential for genome replication [54] . Downstream to cre is internal ribosomal entering sites (IRES). The IRES has role in initiation of viral protein synthesis and shutting down of host cell protein synthesis [53] . Due to the presence of IRES, picornaviruses are able to bind to ribosomes to initiate the protein synthesis.The picornaviruses have no 5 cap (7-methyguanosine), so IRES serves as ribosomal entering site [55] . The 3 UTR follows the ORF (open reading frame) termination codon and contains a short stretch of RNA which folds into specific stem loop structures [56] followed by a poly "A" tract of variable length [57] . This 3 UTR also serves as some functions in genome replication [58] . 3 UTR is specific for each picornavirus. Poly "A" probably plays a role in FMDV translation [59] and replication [60] . The FMDV genome encodes a polyprotein from which four different structural and eight different non-structural proteins are formed by the viral proteases. After translation, the four primary cleavage products are formed: (i) the amino terminal L protease which cleaves at its own carboxy terminus, P1-2A, (ii) the precursor of the capsid proteins (iii) 2BC, and (iv) P3 which is cleaved to make the NSPs [61] . FMDV has two proteinases. The NSP leader proteinses (Lpro) located in the N-terminal region of the polyprotein acts both intra and intermolecularly. This protease initiates cleavage by separating itself from P1, the precursor of the capsid protein and the remainder of the growing polypeptide chain [62] . The 3C protease is responsible for the cleavage of P1 into 1AB (VP0), 1C (VP3), and 1D (VP1). The 1A/1B (VP4/VP2) cleavage occurs at the late stage in virus morphogenesis and is associated with maturation of capsid. The 2C/3A primary cleavage is cis and subsequent cleavage is also mediated by the 3Cpro and producing processing intermediates and mature proteins [63] . In addition to viral protein processing, the 3Cpro cleave the host cell protein histone H3 and may be involved with the shuting down of host cell transcription [64] . The cleavage between 2A/2B junctions is mediated by 2A polypeptide separating itself and P1 away from 2BC/P3 [61] . This change is independent of both L and 3C. The FMDV 2A region is very short (about 18 amino acids) and together with the Nterminal residues of protein 2B, represents an autonomous element capable of mediating cleavage at its own C terminus [65] .