The Middle Subunit of Replication Protein A Contacts Growing RNA-DNA Primers in Replicating Simian Virus 40 Chromosomes |
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Authors: | Gilad Mass Tamar Nethanel Gabriel Kaufmann |
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Affiliation: | Department of Biochemistry, Tel Aviv University, Ramat Aviv 69978, Israel |
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Abstract: | The eukaryotic single-stranded DNA binding protein replication protein A (RPA) participates in major DNA transactions. RPA also interacts through its middle subunit (Rpa2) with regulators of the cell division cycle and of the response to DNA damage. A specific contact between Rpa2 and nascent simian virus 40 DNA was revealed by in situ UV cross-linking. The dynamic attributes of the cross-linked DNA, namely, its size distribution, RNA primer content, and replication fork polarity, were determined. These data suggest that Rpa2 contacts the early DNA chain intermediates synthesized by DNA polymerase α-primase (RNA-DNA primers) but not more advanced products. Possible signaling functions of Rpa2 are discussed, and current models of eukaryotic lagging-strand DNA synthesis are evaluated in view of our results. |
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