A viral vector comprising (a) a cDNA of a recombinant viral RNA having a sequence in which a foreign gene is inserted into a sequence carrying at least N gene, X gene, P gene and L gene of a Borna disease virus genome, said genes being arranged in the same order as in the Borna disease virus genome, (b) a DNA encoding a ribozyme, and (c) a promoter sequence, wherein (b) is located upstream and downstream of (a) and (a) and (b) are located downstream of (c), characterized in that (a) is a cDNA of a recombinant viral RNA in which G gene in the Borna disease virus genome is disrupted and the sequence of G gene of an avian Borna virus genome is also present. The present invention can be appropriately used, as a gene transfer technique not affecting the host chromosome, in various fields of, for example, treating and preventing brain nervous system diseases, techniques for visualizing neural cells in the brain neurology area, etc.
BORNA VIRAL VECTOR AND UTILIZATION THEREOF