Current theories suggest that progressive age-associated declines in tissue function are caused by changes in intrinsic processes, and that these can occur in the absence of disease. We hypothesize that components of eukaryotic gene regulatory processes may be intrinsically altered by aging to cause increased or decreased gene expression, in turn producing the observed declines in tissue functions. Following such systemic injuries as bacterial lipopolysaccharide (LPS) mediated acute inflammation, the liver responds with a striking increase in the synthesis of a subset of serum proteins, the acute phase reactants (APR). Our preliminary studies indicate that aging affects the regulation of one of the APR genes, the alpha1-acid glycoprotein (AGP) gene. Changes include (a) an increase in the constitutive level of the AGP MRNA pool, and (b) slowed induction of AGP by LPS. In this project we will use the AGP gene as a model to determine whether the structure and function of regulatory factors are affected by aging. AGP MRNA levels will be determined to establish complete LPS-stimulated induction curves in 2, 12, and 24 month Balb/cNNia mice, and nuclear run-on analyses will be done to ask if aging alters both constitutive and LPS-inducible levels of AGP gene transcription in aged mice. Preliminary studies have shown that the mouse AGP promoter has two trans-acting factor binding sites, namely region B (-104 to -91) and region C (-125 to -104), and that the binding activity of these factors may be altered in aged animals. In addition the proteins that binding activity of these factors may be altered in aged animals. In addition the proteins that bind to region C have been identified as C/EBPalpha (constitutive) and C/EBPbeta (LPS-inducible). To determine if trans-acting factors of the AGP promoter are altered in aged animals, activity of these factors will be determined by Dnase I (in vitro) and in vivo footprinting, and gel- shift/Scatchard plot analysis. Experiments will be done to ask whether age-associated structural changes in these trans-acting factors is the basis for their altered binding activity. These experiments include protein modification by phosphorylation and homodimer/heterodimer function. Trans-acting factor MRNA and protein levels will be analyzed to determine if aging affects the expression of their genes. An in vitro transcription assay system will also be developed in order to conduct functional assays of the trans-acting factors. Our long range goal is to determine how gene regulation at the transcriptional or post transcriptional level is intrinsically affected by aging.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
5P01AG010514-03
Application #
3746244
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Type
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Hegde, Muralidhar L; Mantha, Anil K; Hazra, Tapas K et al. (2012) Oxidative genome damage and its repair: implications in aging and neurodegenerative diseases. Mech Ageing Dev 133:157-68
Tann, Anne W; Boldogh, Istvan; Meiss, Gregor et al. (2011) Apoptosis induced by persistent single-strand breaks in mitochondrial genome: critical role of EXOG (5'-EXO/endonuclease) in their repair. J Biol Chem 286:31975-83
Zhang, Haihong; Xie, Chenghui; Spencer, Horace J et al. (2011) Obesity and hepatosteatosis in mice with enhanced oxidative DNA damage processing in mitochondria. Am J Pathol 178:1715-27
Szczesny, Bartosz; Tann, Anne W; Mitra, Sankar (2010) Age- and tissue-specific changes in mitochondrial and nuclear DNA base excision repair activity in mice: Susceptibility of skeletal muscles to oxidative injury. Mech Ageing Dev 131:330-7
Szczesny, Bartosz; Tann, Anne W; Longley, Matthew J et al. (2008) Long patch base excision repair in mammalian mitochondrial genomes. J Biol Chem 283:26349-56
Szczesny, Bartosz; Mitra, Sankar (2005) Effect of aging on intracellular distribution of abasic (AP) endonuclease 1 in the mouse liver. Mech Ageing Dev 126:1071-8
Choksi, K B; Boylston, W H; Rabek, J P et al. (2004) Oxidatively damaged proteins of heart mitochondrial electron transport complexes. Biochim Biophys Acta 1688:95-101
Garg, Nisha; Gerstner, Arpad; Bhatia, Vandanajay et al. (2004) Gene expression analysis in mitochondria from chagasic mice: alterations in specific metabolic pathways. Biochem J 381:743-52
Rabek, Jeffrey P; Boylston 3rd, William H; Papaconstantinou, John (2003) Carbonylation of ER chaperone proteins in aged mouse liver. Biochem Biophys Res Commun 305:566-72
Dou, Hong; Mitra, Sankar; Hazra, Tapas K (2003) Repair of oxidized bases in DNA bubble structures by human DNA glycosylases NEIL1 and NEIL2. J Biol Chem 278:49679-84

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