Nuclease interferon-induced

Duplex Substitution1) of 2 -OH by Strand modified Molecular size (s20,w) Purine Pyrimidine strand strand Thermal stability (7m °C) 0.1 M Na+ 0.15 MNa+ Resistance of the modified strand to degradation by nucleases Interferon-inducing activity of the duplex References... 

That resistance to nucleolytic degradation may play an important part in the interferon-inducing capacity of poly(I) poly(C) and other double-stranded polyribonucleotides is suggested by the aforementioned findings pointing to a parallel increase of interferon production and resistance to nucleases upon... 

There appears to be a considerable worldwide effort to develop treatments for viral diseases. The prophylaxis of some diseases by vaccines, where available, remains a valuable method. The acceleration of work with human interferon is gratifying. The concept of using small organic compounds of nuclease-resistant polymeric polynucleotides as interferon inducers has had dubious results in humans, but may still be viable if therapeutic ratios can be improved. Immunoenhancing substances such as tilorone, levamisole, BCG vaccine, and others under investigation have had a limited impact thus far. Neither approach represents chemotherapy in the classic sense and was therefore not discussed here. 

In mouse L cells, addition of one or two minor species of mammalian leucyl-tRNA were shown to be sufficient to restore translation (27). A similar conclusion was reached with yeast tRNA (28), even with poly(U,C) as template. The type of tRNA to be added appears to depend on the mRNA used (25, 27) and also on the extract Friend cells were reported to require lysyl-tRNA (29). These tRNA species were, however, not absent from interferon-treated cell extracts (24, 27, 50), l> u.t had to be added in excess over what is normally needed. A decreased charging of leu-tRNA or an increased deacylation were reported (5I, 32). Prolonged pre-incubation for 1-2 h of the extracts can increase the interferon-induced elongation block reversed by tRNA (55)-have recently observed that ATP is required to activate the translational inhibition seen in interferon-treated cell extracts without dsRNA. This could be shown by comparing extracts freed of endogenous mRNA activity either by micrococcal nuclease (54) or by pre-incubation with ATP. Table 5 shows that tRNA reversible-inhibition developed when ATP was present. It is not clear yet whether the protein kinase, or E and F may play a role in this inhibition without dsRNA. We also observed an inhibitor of leu-tRNA charging in ribosomal extracts of interferon-treated cells (Schmidt, A. and Revel, M., impublished). 

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