The long term goals of this proposal are to understand the fundamental mechanisms of eukaryotic chromosomal DNA replication and to determine how these mechanisms are disrupted in transformed cells. Transformation of cells involves deregulation of the initiation of chromosomal DNA replication. Therefore, their research will potentially give information concerning the steps of eukaryotic DNA replication that act as regulatory control points inside the cell. They will use simian virus 40 (SV40) as a model system in vitro to explore the mechanism of eukaryotic DNA replication. First, they will isolate and characterize human proteins that physically interact with human replication protein A (hRPA). Second, they have found that the DNA helicase activity of the SV40 large tumor antigen (T antigen) is 15-fold greater when T antigen binds DNA as a double hexamer rather than as a hexamer. The interaction of the T antigen double hexamer with synthetic replication bubble substrates (ie., substrates that contain a central ssDNA region flanked by duplex DNA) will be probed by chemical and enzymatic reagents. They will examine the role of the T antigen double hexamer on unwinding of lengthy DNA molecules, and determine the effect of other replication components on the stability of the T antigen double hexamer. Third, they will characterize the mechanism of DNA unwinding for the T antigen DNA helicase. They will determine the DNA helicase step size and the DNA contacts that T antigen makes during DNA unwinding through the use of ribose-substituted DNA forks. The model that T antigen encircles one of the two single-strands at a replication fork will be tested. Fourth, they will examine the DNA unwinding reaction mediated by hRPA on pseudo-origin substrates. They found previously that hRPA can bind and denature DNA substrates containing a structural feature (an 8 nt bubble) found within the ATP-dependent T antigen-SV40 origin complex. They will examine the role of pseudo-origin sequence and structure on hRPA binding and unwinding of these substrates.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI029963-09
Application #
2699929
Study Section
Virology Study Section (VR)
Program Officer
Wong, May
Project Start
1990-07-01
Project End
2002-06-30
Budget Start
1998-07-01
Budget End
1999-06-30
Support Year
9
Fiscal Year
1998
Total Cost
Indirect Cost
Name
New York University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10016
Xiao, Shu; Caglar, Elif; Maldonado, Priscilla et al. (2014) Induced expression of nucleolin phosphorylation-deficient mutant confers dominant-negative effect on cell proliferation. PLoS One 9:e109858
Anantha, Rachel William; Sokolova, Elena; Borowiec, James A (2008) RPA phosphorylation facilitates mitotic exit in response to mitotic DNA damage. Proc Natl Acad Sci U S A 105:12903-8
Anantha, Rachel W; Vassin, Vitaly M; Borowiec, James A (2007) Sequential and synergistic modification of human RPA stimulates chromosomal DNA repair. J Biol Chem 282:35910-23
Saxena, A; Rorie, C J; Dimitrova, D et al. (2006) Nucleolin inhibits Hdm2 by multiple pathways leading to p53 stabilization. Oncogene 25:7274-88
Kim, Kyung; Dimitrova, Diana D; Carta, Kristine M et al. (2005) Novel checkpoint response to genotoxic stress mediated by nucleolin-replication protein a complex formation. Mol Cell Biol 25:2463-74
Vassin, Vitaly M; Wold, Marc S; Borowiec, James A (2004) Replication protein A (RPA) phosphorylation prevents RPA association with replication centers. Mol Cell Biol 24:1930-43
Borowiec, James A (2004) The toposome: a new twist on topoisomerase IIalpha. Cell Cycle 3:627-8
Daniely, Yaron; Dimitrova, Diana D; Borowiec, James A (2002) Stress-dependent nucleolin mobilization mediated by p53-nucleolin complex formation. Mol Cell Biol 22:6014-22
Iftode, C; Borowiec, J A (2000) 5' --> 3' molecular polarity of human replication protein A (hRPA) binding to pseudo-origin DNA substrates. Biochemistry 39:11970-81
Daniely, Y; Borowiec, J A (2000) Formation of a complex between nucleolin and replication protein A after cell stress prevents initiation of DNA replication. J Cell Biol 149:799-810

Showing the most recent 10 out of 23 publications