Cancer research progress, having benefited greatly from studies on powerful model systems, supports the hypothesis that specific mutations leading to decreased genome stability are critical early events in tumorigenesis. Experiments in yeast and mice show that eukaryotic genome integrity requires the action of the multifunctional enzyme Flap EndoNuclease (FEN-1), and that mutations in FEN-1 result in DNA duplication defects that occur in human tumors and inherited human diseases. Working together with collaborators, the Tainer lab has discovered features of FEN-1, Rnase HII and the processivity factor for DNA polymerase, termed proliferating cell nuclear antigen (PCNA) that support molecular mechanisms for the activities, regulation and coordination of these proteins and of their dynamic complexes in DNA replication and repair. Our experimentally derived hypothesis, which we call the """"""""rotary hand-off"""""""" model, encompasses mechanisms for DNA recognition, precise cleavage to yield ligatable DNA ends, reduced mutations by preventing the generation of gapped or flapped templates, and coordination rather than interference by key proteins that must associate with PCNA. In this renewal, we propose to test individual features of the rotary hand-off model with respect to specificity, activity, and coordination of repair and replication events by PCNA:FEN-1 and related complexes. In concert, the proposed experiments on archaeal, yeast, and human proteins aim to provide the biophysical, biochemical and biological results for a unified understanding of the role of these proteins in genetic integrity and cancer resistance. Overall, this research aims to provide fundamental knowledge on FEN-1 and related complexes relevant to defining their roles in the regulation of genome fidelity and the mechanisms whereby loss of the functions of these coordinated complexes may lead to inheritable genetic defects and the initiation of cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA081967-09
Application #
7263070
Study Section
Chemical Pathology Study Section (CPA)
Program Officer
Pelroy, Richard
Project Start
1999-03-01
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2009-06-30
Support Year
9
Fiscal Year
2007
Total Cost
$334,590
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Tsutakawa, Susan E; Yan, Chunli; Xu, Xiaojun et al. (2015) Structurally distinct ubiquitin- and sumo-modified PCNA: implications for their distinct roles in the DNA damage response. Structure 23:724-733
Tsutakawa, Susan E; Tainer, John A (2015) Bending Forks and Wagging Dogs--It's about the DNA 3' Tail. Mol Cell 58:972-3
Tsutakawa, Susan E; Lafrance-Vanasse, Julien; Tainer, John A (2014) The cutting edges in DNA repair, licensing, and fidelity: DNA and RNA repair nucleases sculpt DNA to measure twice, cut once. DNA Repair (Amst) 19:95-107
Shin, David S; Pratt, Ashley J; Tainer, John A (2014) Archaeal genome guardians give insights into eukaryotic DNA replication and damage response proteins. Archaea 2014:206735
Grasby, Jane A; Finger, L David; Tsutakawa, Susan E et al. (2012) Unpairing and gating: sequence-independent substrate recognition by FEN superfamily nucleases. Trends Biochem Sci 37:74-84
Patel, Nikesh; Atack, John M; Finger, L David et al. (2012) Flap endonucleases pass 5'-flaps through a flexible arch using a disorder-thread-order mechanism to confer specificity for free 5'-ends. Nucleic Acids Res 40:4507-19
Finger, L David; Atack, John M; Tsutakawa, Susan et al. (2012) The wonders of flap endonucleases: structure, function, mechanism and regulation. Subcell Biochem 62:301-26
Querol-Audi, Jordi; Yan, Chunli; Xu, Xiaojun et al. (2012) Repair complexes of FEN1 endonuclease, DNA, and Rad9-Hus1-Rad1 are distinguished from their PCNA counterparts by functionally important stability. Proc Natl Acad Sci U S A 109:8528-33
Tsutakawa, Susan E; Tainer, John A (2012) Double strand binding-single strand incision mechanism for human flap endonuclease: implications for the superfamily. Mech Ageing Dev 133:195-202
Tsutakawa, Susan E; Van Wynsberghe, Adam W; Freudenthal, Bret D et al. (2011) Solution X-ray scattering combined with computational modeling reveals multiple conformations of covalently bound ubiquitin on PCNA. Proc Natl Acad Sci U S A 108:17672-7

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