[The function of helper plasmids from HEP-Flury strain rabies virus on encapsidating the full-length genome of CTN strain].

OBJECTIVE: To identify the helper plasmids from HEP-Flury strain rabies virus that could encapsidate the full-length genome of CTN strain.

METHODS: Four overlapped fragments covering the full-length genome of rabies virus CTN strain were cloned into expression vector. A recombinant full-length genome plasmid (pCTN-GFP) contained the full-length genome of the CTN strain expect for psi gene which was replaced by GFP gene was then constructed using restriction enzyme cleavage and ligation in vitro. In order to obtain the recombinant rabies virus CTN-GFP, the pCTN-GFP was transfected with helper plasmids carrying N, P, L gene of HEP-Flury strain.

RESULTS: The four gene fragments of the genome were amplified and cloned into the expression vector. The recombinant genome cDNA plasmid pCTN-GFP was constructed and subjected to restriction endonuclease digestions. After sequenced to assure no absence and mutations compared with their parental viruses, it was ready for virus rescue. After the transfection of both pCTN-GFP and the helper plasmids from HEP-Flury strain into BHK-21 cells, the recombinant rabies virus CTN-GFP was rescued and confirmed by fluorescence analysis and RT-PCR, which demonstrated that the CTN-GFP was recovered from cloned cDNA.

CONCLUSION: The proteins of HEP-Flury strain rabies virus could encapsidate and transcribe the CTN strain rabies virus RNA genome.