HIGHLY STABLE EXPRESSION OF A FOREIGN GENE FROM RABIES VIRUS VECTORS

A reverse genetics approach was applied to generate a chimeric nonsegm ented negative strand RNA virus, rabies virus (RV) of the Rhabdovirida e family, that expresses a foreign protein. DNA constructs containing the entire open reading frame of the bacterial chloramphenicol acetylt ransferase (CAT) gene and an upstream RV cistron border sequence were inserted either into the nontranslated pseudogene region of a full-len gth cDNA copy of the RV genome or exchanged with the pseudogene region . ,,After intracellular T7 RNA polymerase-driven expression of full-le ngth antigenome RNA transcripts and RV nucleoprotein, phosphoprotein a nd polymerase from transfected plasmids, RVs transcribing novel monoci stronic mRNAs and expressing CAT at high levels, were recovered, The c himeric viruses possessed the growth characteristics of standard RV an d were genetically stable upon serial cell culture passages. CAT activ ity was still observed in cell cultures infected with viruses passaged for more than 25 times. Based on the unprecedented stability of the c himeric RNA genomes, which is most likely due to tbe structure of the rhabdoviral ribonucleoprotein complex, we predict the successful futur e use of recombinant rhabdovirus vectors for displaying foreign antige ns or delivering therapeutic genes.