On the role of ribonucleic acid in animal virus synthesis. I. Studies with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole.

Adenosine, but not guanosine, was capable of blocking the inhibitory effect of 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) on influenza virus multiplication in the chorioallantoic membrane in vitro. At virus inhibitory concentrations DRB caused marked inhibition in uptake of adenosine-8-C(14) into RNA of uninfected host cells, but it had little effect on uptake of C(14)-L-alanine into host cell proteins or on cellular oxygen consumption. The activity of DRB in inhibiting multiplication of the DNA-containing adenovirus was similar to its inhibitory activity on multiplication of the RNA-containing influenza virus. These and earlier results are discussed from the point of view of the important role of RNA in the reproduction of DNA-containing viruses.