We are investigating the impact of oxidized guanine and uracil on telomere integrity and the role of their repair enzymes, 8oxoguanine DNA glycosylase 1 (OGG1) and uracil DNA glycosylase (UNG) in telomere length maintenance, which are summarized as follows: (1) Impact of oxidized guanine lesions on telomeres in budding yeast and mammalian cells: We found that oxidized guanine lesions accumulated in telomeres in budding yeast and mice that were defective in OGG1 function. These base lesions led to changes in telomere length. Furthermore, the level of base lesions determined the degree of telomere length alteration. Thus, OGG1 is critical in excising telomeric oxidized guanines and plays an important role in telomere length maintenance in yeast and mammals. (2) Impact of uracil base modification on telomeres in human: We found that ablation of UNG function led to telomere attrition in human cells. These data suggest that uracil attenuates telomere integrity and that UNG plays a key role in telomeric uracil repair and telomere length maintenance in human. Our overall effort will facilitate our understanding on how base lesions may impact telomere integrity and thus aging.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIAAG000744-03
Application #
7964037
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
2009
Total Cost
$400,201
Indirect Cost
Name
National Institute on Aging
Department
Type
DUNS #
City
State
Country
Zip Code
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Sarkar, Jaya; Liu, Yie (2016) Fanconi anemia proteins in telomere maintenance. DNA Repair (Amst) 43:107-12
Sarkar, Jaya; Wan, Bingbing; Yin, Jinhu et al. (2015) SLX4 contributes to telomere preservation and regulated processing of telomeric joint molecule intermediates. Nucleic Acids Res 43:5912-23
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Vallabhaneni, Haritha; O'Callaghan, Nathan; Sidorova, Julia et al. (2013) Defective repair of oxidative base lesions by the DNA glycosylase Nth1 associates with multiple telomere defects. PLoS Genet 9:e1003639
Lu, Jian; Vallabhaneni, Haritha; Yin, Jinhu et al. (2013) Deletion of the major peroxiredoxin Tsa1 alters telomere length homeostasis. Aging Cell 12:635-44
Ghosh, Avik K; Rossi, Marie L; Singh, Dharmendra Kumar et al. (2012) RECQL4, the protein mutated in Rothmund-Thomson syndrome, functions in telomere maintenance. J Biol Chem 287:196-209
McNeill, Daniel R; Lin, Ping-Chang; Miller, Marshall G et al. (2011) XRCC1 haploinsufficiency in mice has little effect on aging, but adversely modifies exposure-dependent susceptibility. Nucleic Acids Res 39:7992-8004

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