[Localization of genome RNA synthesis in Sendai virus].

Localization of Sendai virus 50S RNA in Ehrlich ascitic carcinoma cells was studied. At 48 hours postinfection virus-specific 50S RNA was found in the nucleus after 30 min exposure to 3H-uridine, and its amount increased after 1-hour exposure to the precursor reaching 18% of the total nucleus virus-specific RNA. After 2-hour or longer exposure to the precursor the amount of 50S RNA in the nuclei decreased considerably and in the cytoplasm in this gradient region a considerable radioactivity appeared. Rapid utilization of 3H-uridine by the cells under these experimental conditions suggests that 50S RNA is synthesized in the nucleus and migrates to the cytoplasm.