Viral and host deoxyribonucleic acid synthesis in Shope fibroma virus-infected cells as studied by means of high-resolution autoradiography.
Incorporation of (3)H-thymidine by BSC-1 cells infected with Shope fibroma virus was studied by means of high-resolution electron microscopic radioautography. One-hour pulses with the radioactive precursor were given at various times after infection, during a one-step growth cycle of the virus. In the cytoplasm of infected cells, reacted grains occurred over foci of viroplasm; these foci are believed to represent the true sites of viral deoxyribonucleic acid (DNA) replication. Shope fibroma virus DNA synthesis began before 3 hr postinfection, reached a maximum at 8 to 9 hr, and then declined rapidly. It was demonstrated that the decline in (3)H-thymidine uptake is correlated with the onset of viral morphogenesis. In comparison with the noninfected culture, the nuclear labeling, which reflects host DNA metabolism, was slightly reduced by 4 hr postinfection. Inhibition became more marked as infection progressed, and host DNA synthesis was almost completely suppressed in late stages of viral development.
D000818:Animals; D001345:Autoradiography; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis*; D004279:DNA, Viral / Q000096:biosynthesis*; D000882:Haplorhini; D007668:Kidney; D008854:Microscopy, Electron; D011212:Poxviridae / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014412:Tumor Virus Infections / Q000378:metabolism*
D004279:DNA, Viral; D014316:Tritium; D004247:DNA; D013936:Thymidine