The goal of this proposal is to understand the mechanistic aspects of cellular responses to L1 activity, to evaluate L1 -induced mutagenesis and its contribution to DNA damage and associated aging, to determine whether this contribution increases with age, and to find out potential variation of this contribution among individuals. These goals are important because the existing data indicate that the DNA damage in the form of double-strand breaks (DSBs) inflicted by the L1-encoded DNA endonuclease is potentially much greater than the insult to the genome caused by the element via insertional mutagenesis. We detected endogenous L1 expression in a number of somatic cells. Therefore this type of DNA damage has consequences for the whole organism, not only for its progeny. We also wish to address the L1 contribution to the DNA damage and associated aging in human stem cells. For these studies we will manipulate L1 expression levels and correlate L1 activity with the resulting DNA damage by western blot analysis, g-H2AX foci staining, and COMET assays in normal cell lines. We will use reporter assay to quantify the mutagenic potential of L1 elements. We will use cultured primary cell models to determine L1 potential to accelerate cellular senescence in somatic and stem cells. Reported ability of L1 elements to inflict DNA damage and its endogenous expression in a number of human tissues fundamentally changes our understanding of the significance of the L1 expression and its impact on the health of the host. This project is designed to determine whether ongoing low levels of L1 expression in somatic and stem cells lead to a steady accumulation of mutations due to the error-prone repair of the DSBs created by the L1 endonuclease. The direct health implication of this discovery would be L1 contribution to mammalian aging and/or age- associated diseases such as cancer. Due to the constant improvement of the health care there is a growing population of older people that is more susceptible to age-associated diseases. Understanding of the molecular mechanisms of aging would contribute to our potential to prevent the onset of aging or age- associated diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01AG030074-05
Application #
8220917
Study Section
National Institute on Aging Initial Review Group (NIA)
Program Officer
Guo, Max
Project Start
2008-03-15
Project End
2013-12-31
Budget Start
2012-03-01
Budget End
2013-12-31
Support Year
5
Fiscal Year
2012
Total Cost
$114,397
Indirect Cost
$8,474
Name
Tulane University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
053785812
City
New Orleans
State
LA
Country
United States
Zip Code
70118
deHaro, Dawn; Kines, Kristine J; Sokolowski, Mark et al. (2014) Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night. Nucleic Acids Res 42:7694-707
Wagstaff, Bradley J; Kroutter, Emily N; Derbes, Rebecca S et al. (2013) Molecular reconstruction of extinct LINE-1 elements and their interaction with nonautonomous elements. Mol Biol Evol 30:88-99
Dauchy, Robert T; Dauchy, Erin M; Hanifin, John P et al. (2013) Effects of spectral transmittance through standard laboratory cages on circadian metabolism and physiology in nude rats. J Am Assoc Lab Anim Sci 52:146-56
Dauchy, Robert T; Dauchy, Erin M; Mao, Lulu et al. (2012) A new apparatus and surgical technique for the dual perfusion of human tumor xenografts in situ in nude rats. Comp Med 62:99-108
Kines, Kristine J; Belancio, Victoria P (2012) Expressing genes do not forget their LINEs: transposable elements and gene expression. Front Biosci (Landmark Ed) 17:1329-44
Dauchy, Robert T; Dupepe, Lynell M; Ooms, Tara G et al. (2011) Eliminating animal facility light-at-night contamination and its effect on circadian regulation of rodent physiology, tumor growth, and metabolism: a challenge in the relocation of a cancer research laboratory. J Am Assoc Lab Anim Sci 50:326-36
Hedges, Dale J; Belancio, Victoria P (2011) Restless genomes humans as a model organism for understanding host-retrotransposable element dynamics. Adv Genet 73:219-62
Belancio, Victoria P (2011) Importance of RNA analysis in interpretation of reporter gene expression data. Anal Biochem 417:159-61
Belancio, Victoria P; Roy-Engel, Astrid M; Pochampally, Radhika R et al. (2010) Somatic expression of LINE-1 elements in human tissues. Nucleic Acids Res 38:3909-22
Belancio, Victoria P; Roy-Engel, Astrid M; Deininger, Prescott L (2010) All y'all need to know 'bout retroelements in cancer. Semin Cancer Biol 20:200-10

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