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Enhancement of Uptake of Simian Virus 40 by Nuclei of Permissive Cells

Summary Simian virus 40 uptake by the nuclei of permissive monkey kidney cells was enhanced by infecting in the presence of MgSO4, DEAE-dextran, or arginine-rich histones, but not in the presence of lysine-rich histones. Nuclear uptake of virus was found to be more efficient in aged monolayer cultures than in freshly formed cell monolayers. Inhibition of cellular protein, RNA, or DNA synthesis did not prevent virus uptake. “Empty” capsids, which are essentially devoid of viral DNA, were taken up by the nuclei of permissive cells even more efficiently than infectious virus. Undegraded polypeptides of parental virus could be detected in the nuclei up to 24 hr after infection. We thank M. McFalls for technical assistance. This study was supported by U.S. Public Health Service Research Grants CA-10594 and CA-10815 from the National Cancer Institute.