Studies on the in vitro adenylation of RNA by vesicular stomatitis virus

Polyadenylate sequences present in RNA synthesized in vitro by purified vesicular stomatitis virus (VSV) are located at the 3′-termini of the RNA chains. These sequences are heterogeneous in length, averaging 140 bases, and are composed entirely of AMP. VSV purified from different cell lines synthesizes RNA containing poly(A) and complete removal of the viral envelope proteins G and M does not affect its synthesis. No poly(A) synthesis was observed with ATP as the only substrate either in the presence or absence of exogenous RNA primers. Cordycepin triphosphate did not inhibit in vitro RNA synthesis or substitute for ATP in the reaction. Poly(A) sequences are added to the product RNAs during or after their release from the genome RNA template. A possible mechanism of the VSV adenylation process is discussed.