Development of a reverse genetics system for the aG strain of rabies virus in China.

The aG rabies virus strain has been attenuated through multiple passages in cells and is now used as a vaccine strain in China. We attempted to develop a reverse genetics system using the aG strain. Recombinant full-length genomic cDNA was flanked by a hammerhead ribozyme and the hepatitis delta virus ribozyme. Three helper plasmids encoding the nucleoprotein, the phosphoprotein, and the large protein were produced and introduced together with a plasmid containing the full-length aG viral genome into BHK-21 cells by transfection. Recombinant virus was successfully recovered from the cloned cDNA under the control of a CMV promoter driven by RNA polymerase II. The recombinant virus was confirmed by RT-PCR, and the titer of the recombinant virus was 6.2 log LD50.

Complete genome sequence of rabies virus CVS-24 from China.

The entire genome of the mouse-adapted rabies virus strain CVS-24 (challenge virus standard 24), was sequenced. The overall length of the genome was 11,927 nucleotide (nt), comprising a leader sequence of 58 nt, a nucleoprotein (N) gene of 1353 nt, phosphoprotein (P) gene of 894 nt, a matrix protein (M) gene of 609 nt, a glycoprotein (G) gene of 1575 nt, an RNA-dependent RNA polymerase (RdRp, L) gene of 6384 nt and a trailer region of 70 nt. There was a TGAAAAAAA (TG7) consensus sequence at the end of each gene, except the G gene which had an AGAAAAAAA sequence at the end, and the L/trailer region had the sequence CGAAAAAAA. Three were AACAYYYCT consensus start signals close to TG7. The five cistrons were separated by intergenic regions (IGRS) of 2, 5, 5, 24 nt, respectively. Residue 333 of the mature G protein, which is considered to be associated with pathogenicity, was Ala in CVS-24. The topology of the phylogenetic trees generated using N protein sequences suggested that CVS-11 and CVS-N2C have a close relationship to CVS-24.