EXPRESSION OF A MURINE LEUKEMIA-VIRUS GAG-ESCHERICHIA COLI RNASE HI FUSION POLYPROTEIN SIGNIFICANTLY INHIBITS VIRUS SPREAD

The antiviral strategy of capsid-targeted viral inactivation (CTVI) wa s designed to disable newly produced virions by fusing a Gag or Gag-Po l polyprotein to a degradative enzyme (e.g., a nuclease or protease) t hat would cause the degradative enzyme to be inserted into virions dur ing assembly. Several new experimental approaches have been developed that increase the antiviral effect of the CTVI strategy on retroviral replication in vitro. A Moloney murine leukemia virus (Mo-MLV) Gag-Esc herichia coli RNase HI fusion has a strong antiviral effect when used prophylacitcally, inhibiting the spread of Mo-MLV and reducing virus t iters 1,500- to 2,500-fold, A significant (similar to 100-fold) overal l improvement of the CTVI prophylactic antiviral effect was produced b y a modification in the culture conditions which presumably increases the efficiency of delivery and expression of the Mo-MLV Gag fusion pol yproteins. The therapeutic effect of Mo-MLV Gag-RNase HI polyproteins is to reduce the production of infectious Mo-MLV up to 18-fold, An Mo- MLV Gag-degradative enzyme fusion junction was designed that can be cl ear ed by the Mo-MLV pretense to release the degradative enzyme.