Rabies virus glycoprotein gene contains a long 3' noncoding region which lacks pseudogene properties

Abstract

Analysis of a limited number of laboratory strains of rabies virus had demonstrated the presence of a genome region bounded by two transcription termination and polyadenylation-like (TTP) signals (approximately 400 to 450 nucleotides apart) which was located between the end of the glycoprotein (G) coding sequence and the beginning of the L polymerase coding sequence. Although this region had been suggested to represent a remnant or pseudogene (psi), no detailed analysis had been carried out to examine this possibility. Here we present the nucleotide sequence analysis of this genome region for several laboratory rabies virus strains and a large number of diverse rabies viruses detected directly in brain tissue of naturally infected animals. Only one distinct lineage of the laboratory strains and none of the wild-type rabies viruses contained the upstream TTP-like signal, indicating that only the downstream TTP motif is the authentic G mRNA transcription termination and polyadenylation and signal. Phylogenetic analysis of sequence differences provided no evidence of laboratory strains containing the two TTP-like signals being ancestral to any of the viruses possessing only the downstream TTP sequence motif. These data indicate that this region of the rabies virus genome encodes a G mRNA with a long 3' noncoding region with no evidence of a pseudogene.