The non-structural leader protein gene of foot-and-mouth disease virus is highly variable between serotypes.
Aphthoviruses are unique among picornaviruses in that they alone encode a functional L proteinase as the first component of the viral polyprotein. The L genes of a few Indian foot-and-mouth disease viruses were sequenced and compared with those available to study the extent of variation in this gene. Besides the two in-frame start codons present in all FMDV L genes, the Asia-I vaccine virus had an additional in-frame AUG (start) codon, at codon position 3. Amino acid sequence comparison revealed that 39.8% of positions were capable of accepting replacements, yet the residues of the catalytic dyad were totally conserved. Sequence comparison at the C-terminus of the protein indicated that K/R decreasing GAGQS is sufficient for L/P1 cleavage. Phylogenetic analysis based on the L gene sequences did not reveal any serotype-specific clustering. The probable implications of the observed high variability in this non-structural gene is briefly discussed.
George
M
M
Central Laboratory, All India Coordinated Research Project for Epidemiological Studies on Foot-and-Mouth Disease, Indian Veterinary Research Institute, Mukteswar-Kumanon, Nainital.
Venkataramanan
R
R
Gurumurthy
C B
CB
Hemadri
D
D
D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics*; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics*
D004279:DNA, Viral; D017361:Viral Nonstructural Proteins