G-rich DNA can form structures stabilized by interactions between guanines, referred to as G4 DNA. These structures have been widely studied in vitro, but until recently had not been shown to form in vivo. My laboratory has very recently directly identified G4 DNA formed in vivo. Building upon and extending this result, we now propose to study in detail how G4 DNA forms, how it is eliminated from living cells, and whether G4 DNA contributes to genomic instability. To that end we will pursue the following specific aims: (1) We will ask if G4 DNA forms at two G-rich genes, c-myc and the rDNA repeats; (2) we will ask whether G4 DNA formation contributes to genomic instability in yeast; (3) we will study instability of G-rich repeats in human cells, and the functions of BLM helicase in their maintenance; (4) we will identify the conserved motif(s) within RecQ family helicases that specify G4 DNA interaction, and create the corresponding mutants to study functions of enzymes in this family in vivo;, and (5) we will ask how mismatch repair factors participate in elimination of G4 DNA. Results from experiments in this proposal will extend our understanding of G4 DNA formation in living cells, characterize pathways that promote its elimination, and establish its contribution to genomic instability that leads to genetic disease and development of malignancy.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM065988-04
Application #
6917820
Study Section
Special Emphasis Panel (ZRG1-CG (01))
Program Officer
Portnoy, Matthew
Project Start
2002-08-01
Project End
2008-07-31
Budget Start
2005-08-01
Budget End
2006-07-31
Support Year
4
Fiscal Year
2005
Total Cost
$291,935
Indirect Cost
Name
University of Washington
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Gray, Lucas T; Vallur, Aarthy C; Eddy, Johanna et al. (2014) G quadruplexes are genomewide targets of transcriptional helicases XPB and XPD. Nat Chem Biol 10:313-8
Eddy, Johanna; Vallur, Aarthy C; Varma, Sudir et al. (2011) G4 motifs correlate with promoter-proximal transcriptional pausing in human genes. Nucleic Acids Res 39:4975-83
Vallur, Aarthy C; Maizels, Nancy (2010) Distinct activities of exonuclease 1 and flap endonuclease 1 at telomeric g4 DNA. PLoS One 5:e8908
Eddy, Johanna; Maizels, Nancy (2009) Selection for the G4 DNA motif at the 5' end of human genes. Mol Carcinog 48:319-25
Eddy, Johanna; Maizels, Nancy (2008) Conserved elements with potential to form polymorphic G-quadruplex structures in the first intron of human genes. Nucleic Acids Res 36:1321-33
Vallur, Aarthy C; Maizels, Nancy (2008) Activities of human exonuclease 1 that promote cleavage of transcribed immunoglobulin switch regions. Proc Natl Acad Sci U S A 105:16508-12
Duquette, Michelle L; Huber, Michael D; Maizels, Nancy (2007) G-rich proto-oncogenes are targeted for genomic instability in B-cell lymphomas. Cancer Res 67:2586-94
Eddy, Johanna; Maizels, Nancy (2006) Gene function correlates with potential for G4 DNA formation in the human genome. Nucleic Acids Res 34:3887-96
Maizels, Nancy (2006) Dynamic roles for G4 DNA in the biology of eukaryotic cells. Nat Struct Mol Biol 13:1055-9
Huber, Michael D; Duquette, Michelle L; Shiels, Jerome C et al. (2006) A conserved G4 DNA binding domain in RecQ family helicases. J Mol Biol 358:1071-80

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