Ribonucleic acid synthesis in cells infected with Newcastle disease virus

Abstract

Chick embryo cells in tissue culture infected with Newcastle disease virus incorporate [3H]uridine into at least four viral-specific RNA components in the presence of actinomycin D. The three RNA components which are found in greatest amount, 18, 22 and 35 s, are predominantly single stranded and almost completely complementary to viral RNA. They probably share base sequences in part and their sum does not complete the entire complement of viral RNA. The fourth viral-specific RNA component found in infected cells sediments with characteristics of viral RNA (57 s) and is present in smaller amounts than are the other three. Annealing studies indicate that the 57 s component probably consists of a mixture of viral RNA and its intact complement in a ratio of about 2 to 1. A small and variable amount of base-paired RNA, which is resistant to digestion by pancreatic RNase, is found in the 35 s and 57 s components. All four labeled RNA components are found almost exclusively in the cytoplasm after incubating infected cells with [3H]uridine in the presence of actinomycin D for 15 minutes. Further, most of the viral specific RNA is attached to polyribosomes in the cell. The function of the complementary RNA pieces is not known.