Influence of the xyloadenosine analogue of 2',5'-oligoriboadenylate on poly(A)-specific, 2',5'-oligoriboadenylate degrading 2',3'-exoribonuclease and further enzymes involved in poly(A)(+)mRNA metabolism.

The homogeneous poly(A)-specific 2',3'-exoribonuclease from calf thymus gland, which cleaves both 3',5'- and 2',5'-linked oligoriboadenylates, does not degrade (xyloA2'p)2 xyloA, the xylofuranosyladenosine analogue of the 2-5A core. This oligonucleotide, which is supposed to enter intact cells rapidly, was found to possess an increased stability and an enhanced antiherpesvirus activity compared to the natural (A2'p)2A (Eppstein, D.A., Barnett, J.W., Marsh, Y.V., Gosselin, G. and Imbach, J.-L. (1983) Nature 302, 723-724). The poly(A) anabolic enzyme, poly(A) polymerase (Mn2+-dependent), from the same source, which is initiated by (A3'p)2A and its higher oligomers, does not accept 2-5A core and its xyloadenosine analogue as primer. Both oligonucleotides exert no influence on endoribonuclease IV and on the integrity of the poly(A)-ribonucleoprotein complex.