The papillomavirus (PV) protein E2 is one of only two proteins required for viral DNA replication. E2 is the viral transcriptional regulator/activation protein as well as the initiator of viral DNA replication. E2 is known to interact with various cellular DNA replication proteins, including the PV E1 protein, the cellular ssDNA binding complex (RPA), and topoisomerase I. Recently, we observed that cellular DNA polymerase ε (pol ε) interacts with the PV helicase protein, E1. E1 stimulates its activity with a very high degree of specificity, implicating pol ε in PV DNA replication. In this paper, we evaluated whether E2 also shows a functional interaction with pol ε. We found that E2 stimulates the DNA synthesis activity of pol ε, independently of pol ε’ s processivity factors, RFC, PCNA, and RPA, or E1. This appears to be specific for pol ε, as cellular DNA polymerase δ is unaffected by E1. However, unlike other known stimulatory factors of pol ε, E2 does not affect the processivity of pol ε. The domains of E2 were analyzed individually and in combination for their ability to stimulate pol ε. Both the transactivation and hinge domains were found to be important for this stimulation, while the E2 DNA-binding domain was dispensable. These findings support a role for E2 beyond E1 recruitment in viral DNA replication, demonstrate a novel functional interaction in PV DNA replication, and further implicate cellular pol ε in PV DNA replication.
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http://dx.doi.org/10.3390/v10060321 | DOI Listing |
Sci Rep
January 2025
School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA.
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January 2025
Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798-7348, USA. Electronic address:
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January 2025
Gladstone Institutes, San Francisco, CA, USA; Department of Urology, UCSF, San Francisco, CA, USA. Electronic address:
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MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, No.866 Yuhangtang Road, 310058, Hangzhou, China.
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View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
Oscillation of the active form of the initiator protein DnaA (ATP-DnaA) allows for the timely regulation for chromosome replication. After initiation, DnaA-bound ATP is hydrolyzed, producing inactive ADP-DnaA. For the next round of initiation, ADP-DnaA interacts with the chromosomal locus DARS2 bearing binding sites for DnaA, a DNA-bending protein IHF, and a transcription activator Fis.
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