Evidence for genetic relationship between RNA and DNA viruses from the sequence homology of a putative polymerase gene of bluetongue virus with that of vaccinia virus: conservation of RNA polymerase genes from diverse species.

The nucleotide sequence of segment 1 of the double stranded RNA genome of bluetongue virus serotype 10 (BTV-10), encoding the largest viral core protein, VP1, has been determined. Linear sequence analysis of the predicted amino acid sequence of the 149-K Da protein, a putative component of the viral RNA-directed RNA polymerase, revealed extensive homology with the vaccinia virus 147K Da DNA-directed RNA polymerase subunit. Similar homologies were detected between the VP1 polypeptide and the beta chain subunit of Escherichia coli and common tobacco chloroplast RNA polymerases, yeast RNA polymerase II and III and fruit fly polymerase II.