Control of simian virus 40 DNA replication by the HeLa cell nuclear kinase casein kinase I.
The initiation of simian virus 40 (SV40) DNA replication is regulated by the phosphorylation state of the viral initiator protein, large T antigen. We describe the purification from HeLa cell nuclei of a 35-kDa serine/threonine protein kinase that phosphorylates T antigen at sites that are phosphorylated in vivo and thereby inhibits its ability to initiate SV40 DNA replication. The inhibition of both origin unwinding and DNA replication by the kinase is reversed by protein phosphatase 2A. As determined by molecular weight, substrate specificity, autophosphorylation, immunoreactivity, and limited sequence analysis, this kinase appears to be identical to casein kinase I, a ubiquitous serine/threonine protein kinase that is closely related to a yeast kinase involved in DNA metabolism. The HeLa cell phosphorylation cycle that controls the initiation of SV40 DNA replication may also play a role in cellular DNA metabolism.
Department of Cellular, Viral and Molecular Biology, University of Utah, Salt Lake City 84112.
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Cegielska
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Virshup
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D047388:Casein Kinases; D002467:Cell Nucleus / Q000201:enzymology / Q000382:microbiology; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D054648:Protein Phosphatase 2; D013539:Simian virus 40 / Q000235:genetics*; D013696:Temperature
D004279:DNA, Viral; D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D047388:Casein Kinases; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2