Detection of polyadenylic acid sequences in viral and eukaryotic RNA(polu(U)-cellulose columns-poly(U) filters-fiberglass-HeLa cells-bacteriophage T4).

A rapid and specific technique to detect polyriboadenylic acid sequences in RNA is described. The method depends upon the ability of RNAs that contain poly(A) sequences to associate specifically with poly(U) that has been immobilized on fiberglass filters by ultraviolet irradiation. A high proportion of the transcripts synthesized in vivo and in vitro from the vaccinia virus genome contain poly(A) sequences and bind to the poly(U) filters. Similarly, DNA-like RNA from the nucleus and from the cytoplasmic polyribosomes of HeLa cells is rich in species that bind to poly(U) filters. Poly(U) immobilized on cellulose powder is useful to make columns with a high capacity for the binding and purification of poly(A)-containing RNAs.

Mechanism of synthesis of vaccinia virus double-stranded ribonucleic acid in vivo and in vitro.

The synthesis of vaccinia virus double-stranded ribonucleic acid (RNA) in infected HeLa cells was sensitive to actinomycin D, suggesting that a deoxyribonucleic acid dependent reaction is involved. Some double-stranded RNA was made in the presence of cytosine arabinoside in infected cells. Double-stranded and complementary RNA were synthesized in vitro by using vaccinia cores. These two observations indicate that some of the double-stranded RNA is read from "early" genes. The double-stranded RNA synthesized in vitro had the same properties as that made in vivo. At least 70% of the double-stranded RNA made in vivo was in ribonuclease-resistant form prior to sodium dodecyl sulfate-phenol extraction. In addition, there was a complementary RNA in infected cells which could be converted to double-stranded RNA by annealing.