Gene 2 of the Sigma Rhabdovirus Genome Encodes the P Protein, and Gene 3 Encodes a Protein Related to the Reverse Transcriptase of Retroelements

The nucleotide sequence of the genes 2 and 3 of theDrosophilarhabdovirus sigma was determined from cDNAs to viral genome and poly(A)+mRNAs. Gene 2 comprises 1032 nucleotides and contains a long ORF encoding a molecular weight 35,208 polypeptide present in infected cells and in virions which migrates in SDS–PAGE as a doublet ofMrabout 60 kDa. The distribution of acidic charges as well as the electrophoretic properties of the protein are characteristic of the rhabdovirus P proteins. Gene 3 comprises 923 nucleotides and contains a long ORF capable of coding a polypeptide of 298 amino acids of MW 33,790. The putative protein (PP3) is similar in size to a minor component of the virions. Computer analysis shows that the sequence of PP3 contains three motifs related to the conserved motifs of reverse transcriptases.