This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Trowbridge, P. W.
Right arrow Articles by Simmons, D. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Trowbridge, P. W.
Right arrow Articles by Simmons, D. T.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, March 1999, p. 1686-1694, Vol. 19, No. 3
0270-7306/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Human Topoisomerase I Promotes Initiation of Simian Virus 40 DNA Replication In Vitro

Pamela W. Trowbridge, Rupa Roy, and Daniel T. Simmons*

Department of Biological Sciences, University of Delaware, Newark, Delaware 19716-2590

Received 25 September 1998/Returned for modification 26 October 1998/Accepted 23 November 1998

Addition of purified human topoisomerase I (topo I) to simian virus 40 T antigen-driven in vitro DNA replication reactions performed with topo I-deficient extracts results in a greater than 10-fold stimulation of completed molecules as well as a more than 3-fold enhancement of overall DNA replication. To further characterize this stimulation, we first demonstrate that bovine topo I but not Escherichia coli topo I can also enhance DNA replication. By using several human topo I mutants, we show that a catalytically active form of topo I is required. To delineate whether topo I influences the initiation or the elongation step of replication, we performed delayed pulse, pulse-chase, and delayed pulse-chase experiments. The results illustrate that topo I cannot promote the completion of partially replicated molecules but is needed from the beginning of the reaction to initiate replication. Competitive inhibition experiments with the topo I binding T antigen fragment 1-246T and a catalytically inactive topo I mutant suggest that part of topo I's stimulation of replication is mediated through a direct interaction with T antigen. Collectively, our data indicate that topo I enhances the synthesis of fully replicated DNA molecules by forming essential interactions with T antigen and stimulating initiation.

* Corresponding author. Mailing address: Department of Biological Sciences, University of Delaware, Newark, DE 19716-2590. Phone: (302) 831-8547. Fax: (302) 831-2281. E-mail: dsimmons{at}udel.edu.

Molecular and Cellular Biology, March 1999, p. 1686-1694, Vol. 19, No. 3
0270-7306/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:

  • Khopde, S., Simmons, D. T. (2008). Simian Virus 40 DNA Replication Is Dependent on an Interaction between Topoisomerase I and the C-Terminal End of T Antigen. J. Virol. 82: 1136-1145 [Abstract] [Full Text]  
  • Wang, W., Manna, D., Simmons, D. T. (2007). Role of the Hydrophilic Channels of Simian Virus 40 T-Antigen Helicase in DNA Replication. J. Virol. 81: 4510-4519 [Abstract] [Full Text]  
  • Hu, Y., Clower, R. V., Melendy, T. (2006). Cellular Topoisomerase I Modulates Origin Binding by Bovine Papillomavirus Type 1 E1. J. Virol. 80: 4363-4371 [Abstract] [Full Text]  
  • Simmons, D. T., Gai, D., Parsons, R., Debes, A., Roy, R. (2004). Assembly of the replication initiation complex on SV40 origin DNA. Nucleic Acids Res 32: 1103-1112 [Abstract] [Full Text]  
  • Jiao, J., Simmons, D. T. (2003). Nonspecific Double-Stranded DNA Binding Activity of Simian Virus 40 Large T Antigen Is Involved in Melting and Unwinding of the Origin. J. Virol. 77: 12720-12728 [Abstract] [Full Text]  
  • Roy, R., Trowbridge, P., Yang, Z., Champoux, J. J., Simmons, D. T. (2003). The Cap Region of Topoisomerase I Binds to Sites near Both Ends of Simian Virus 40 T Antigen. J. Virol. 77: 9809-9816 [Abstract] [Full Text]  
  • Kautz, A. R., Weisshart, K., Schneider, A., Grosse, F., Nasheuer, H.-P. (2001). Amino Acids 257 to 288 of Mouse p48 Control the Cooperation of Polyomavirus Large T Antigen, Replication Protein A, and DNA Polymerase {alpha}-Primase To Synthesize DNA In Vitro. J. Virol. 75: 8569-8578 [Abstract] [Full Text]  
  • Kautz, A. r., Schneider, A., Weisshart, K., Geiger, C., Nasheuer, H.-P. (2001). Different Regions of Primase Subunit p48 Control Mouse Polyomavirus and Simian Virus 40 DNA Replication In Vitro. J. Virol. 75: 1751-1760 [Abstract] [Full Text]  
  • Gai, D., Roy, R., Wu, C., Simmons, D. T. (2000). Topoisomerase I Associates Specifically with Simian Virus 40 Large-T-Antigen Double Hexamer-Origin Complexes. J. Virol. 74: 5224-5232 [Abstract] [Full Text]  
  • Mo, Y.-Y., Wang, C., Beck, W. T. (2000). A Novel Nuclear Localization Signal in Human DNA Topoisomerase I. J. Biol. Chem. 275: 41107-41113 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»