Sendai virus nucleocapsids in the nucleoli of infected cells

Summary Uncoiled parental Sendai virus nucleocapsids were revealed in the nucleoli of Sendai virus infected Ehrlich ascites tumor cells early in infection. Their sedimentation coefficient and buoyant density were similar to that of parental nucleocapsids isolated from the cytoplasm (150–180S in a sucrose gradient and 1.35–1.37 g/ml in a CsCl gradient). Later in infection the nucleocapsids were involved into complexes with a sedimentation coefficient about 500S. Similar results were obtained with nucleoli of chicken embryo lung cells. The complex in Ehrlich tumor cells contained 23–26S nascent RNA, its synthesis being inhibited by cycloheximide.