Comparative sequence analyses of B5R gene of Indian Camelpox virus isolates with other orthopoxviruses

Camelpox virus (CMLV), the causative agent of camelpox, is a poorly characterized orthopoxvirus in India, which causes a severe and economically important disease especially in young camels. B5R protein of orthopoxviruses is one of the principal constituents of virus envelope and is essential for the formation of extracellular enveloped virus. The B5R protein is prone for variation due to immune pressure. We determined the complete nucleotide sequence of B5R gene of three Indian CMLV isolates and compared them with other members to understand its phylogenic relationship with other orthopoxvirus. Like in variola or vaccinia viruses, the B5R gene in CMLV is 954 nucleotides in length encoding a polypeptide of 317 amino acids. Sequence analyses of B5R gene revealed 99.4 to 99.8% and 98.4 to 99.7% identities among the CMLV isolates at the nucleotide and amino acid levels, respectively. Greater sequence identity with variola virus (96.9 to 97.8%) and other members of the orthopoxvirus (93.8 to 96.6%) showed highly conserved nature of the protein. Phylogenetic analyses based on deduced amino acid sequence of B5R revealed that CMLVs are closely related to variola virus than to any other member species of orthopoxvirus.