USE OF A NONVIRAL VECTOR TO EXPRESS A CHIMERIC TRANSFER-RNA-RIBOZYME AGAINST LYMPHOCYTIC CHORIOMENINGITIS VIRUS - CYTOPLASMIC ACCUMULATION OF A CATALYTICALLY COMPETENT TRANSCRIPT BUT MINIMAL ANTIVIRAL EFFECT

RNA polymerase III promoters direct the ubiquitous, high-level, expres sion of small, stable RNAs, such as tRNAs, and thus are attractive can didates for achieving stable expression of small therapeutic (e.g., an tiviral) molecules, such as ribozymes or antisense RNAs, In this artic le, we describe the use of a nonviral vector containing a tRNA promote r to express an antilymphocytic choriomeningitis virus (LCMV) ribozyme (tRNA-Rib5), The chimeric tRNA-ribozyme is specifically and efficient ly transcribed by pol III in cell-free extracts, and the resulting tra nscript has appropriate ribozyme activity, In tissue culture studies, high levels of chimeric transcripts were readily detectable and were t ransported to the cytoplasm, the site of LCMV replication, Despite acc umulation of tRNA-Rib5 in the cytoplasm of stably transformed cell clo nes, antiviral effects were minimal or absent, The implications of the se findings and the potential use of this vector system for in vivo st udies requiring the delivery of small molecules are discussed.