Ubiquitous repair mechanisms have evolved to remove DNA lesions, (both endogenous and those induced by genotoxic agents), that have been implicated in mutagenesis, cancer, and aging. Small mutagenic alkyl and cyclic ethenobase adducts induced by simple carcinogens, such as vinyl chloride and antitumor drugs, e.g., cyclophosphamide, are repaired via the base excision repair (BER) pathway; its first step is removal of the adduct by N-methylpurine-DNA glycosylase (MPG), generating abasic (AP) sites. In mammalian cells, only one MPG with a wide substrate range has so far been characterized. Furthermore, AP sites, also generated spontaneously and by other DNA glycosylases, are themselves cytotoxic and mutagenic; the first step tin their repair is DNA strand cleavage by AP-endonucleases (APE). The major mammalian APE (APE-1) also activates transcription factor AP-1 and is itself a repressor in Ca2+-dependent gene regulation. The molecular mechanisms of mammalian MPGs and APEs are not known. In particular, the mechanism of MPG, with a broad substrate range, should be significantly different from that of the well-characterized uracil-DNAglycosylase. The availability of molecular probes for human and mouse MPGs and APEs provides a unique opportunity for a comprehensive investigation of their reaction mechanisms and in vivo functions.
The specific aims of this continuing project are: (1) to characterize the mechanisms of lesion recognition and catalysis by mammalian MPG's; (2) to elucidate the mechanisms of multiple functions of human APE-1; (3) to test the hypothesis that BER proteins form a repairosome complex; (4) to isolate MPG-negative mice and cell lines in order to evaluate the etiologic role of specific lesions in tumorigenesis, mutagenesis and toxicity; and (5) to isolate APE-1 negative human cells for elucidating the role of AP sites in spontaneous and induced mutations. The long range objectives of this project are to characterize the repair proteins responsible for repairing alkylation and oxidative damage in mammalian genomes, and their regulation, and eventually to develop approaches for deliberately modulating repair in normal and tumor cells.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA053791-10
Application #
2894867
Study Section
Chemical Pathology Study Section (CPA)
Program Officer
Okano, Paul
Project Start
1991-02-11
Project End
2001-04-30
Budget Start
1999-05-01
Budget End
2000-04-30
Support Year
10
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Suganya, Rangaswamy; Chakraborty, Anirban; Miriyala, Sumitra et al. (2015) Suppression of oxidative phosphorylation in mouse embryonic fibroblast cells deficient in apurinic/apyrimidinic endonuclease. DNA Repair (Amst) 27:40-8
Szczesny, Bartosz; Brunyanszki, Attila; Olah, Gabor et al. (2014) Opposing roles of mitochondrial and nuclear PARP1 in the regulation of mitochondrial and nuclear DNA integrity: implications for the regulation of mitochondrial function. Nucleic Acids Res 42:13161-73
Tsutakawa, Susan E; Shin, David S; Mol, Clifford D et al. (2013) Conserved structural chemistry for incision activity in structurally non-homologous apurinic/apyrimidinic endonuclease APE1 and endonuclease IV DNA repair enzymes. J Biol Chem 288:8445-55
Sengupta, Shiladitya; Mitra, Sankar; Bhakat, Kishor K (2013) Dual regulatory roles of human AP-endonuclease (APE1/Ref-1) in CDKN1A/p21 expression. PLoS One 8:e68467
Szczesny, Bartosz; Olah, Gabor; Walker, Dillon K et al. (2013) Deficiency in repair of the mitochondrial genome sensitizes proliferating myoblasts to oxidative damage. PLoS One 8:e75201
Hegde, Muralidhar L; Izumi, Tadahide; Mitra, Sankar (2012) Oxidized base damage and single-strand break repair in mammalian genomes: role of disordered regions and posttranslational modifications in early enzymes. Prog Mol Biol Transl Sci 110:123-53
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
Mantha, Anil K; Dhiman, Monisha; Taglialatela, Giulio et al. (2012) Proteomic study of amyloid beta (25-35) peptide exposure to neuronal cells: Impact on APE1/Ref-1's protein-protein interaction. J Neurosci Res 90:1230-9
Sengupta, Shiladitya; Chattopadhyay, Ranajoy; Mantha, Anil K et al. (2012) Regulation of mouse-renin gene by apurinic/apyrimidinic-endonuclease 1 (APE1/Ref-1) via recruitment of histone deacetylase 1 corepressor complex. J Hypertens 30:917-25
Hegde, Muralidhar L; Hegde, Pavana M; Arijit, Dutta et al. (2012) Human DNA Glycosylase NEIL1's Interactions with Downstream Repair Proteins Is Critical for Efficient Repair of Oxidized DNA Base Damage and Enhanced Cell Survival. Biomolecules 2:564-78

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