4,5-S-RNAI in virus-specific polyribosomes from ascitic Krebs 2 carcinoma cells infected with encephalomyocarditis virus

Polyribosomes of Krebs 2 ascite carcinoma cells non-infected and infected with encephalomyocarditis (EMC) virus contain a heterogeneous population of low molecular weight small RNAs. Analysis of the RNAs by polyacrylamide gel electrophoresis did not reveal any qualitative differences in the small RNA sets within the composition of polyribosomes from virus-infected and non-infected cells. However, the content of one of the small RNAs was markedly elevated in polyribosomes from virus-infected cells. As can be followed from partial determination of its primary structure, this small mRNA is identical to 4,5S-RNAI previously detected in the nuclei of Novikov hepatoma cells of the rat. The data obtained suggest that 4,5S-RNAI can be involved in the regulation of protein synthesis in virus-infected cells.