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Mangiapane G, Notarangelo M, Canarutto G, Fabbiano F, Dalla E, Degrassi M, Antoniali G, Gualandi N, De Sanctis V, Piazza S, D'Agostino VG, Tell G. The DNA-repair protein APE1 participates with hnRNPA2B1 to motif-enriched and prognostic miRNA secretion. Oncogene 2024; 43:1861-1876. [PMID: 38664500 DOI: 10.1038/s41388-024-03039-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 06/12/2024]
Abstract
The base excision repair (BER) Apurinic/apyrimidinic endonuclease 1 (APE1) enzyme is endowed with several non-repair activities including miRNAs processing. APE1 is overexpressed in many cancers but its causal role in the tumorigenic processes is largely unknown. We recently described that APE1 can be actively secreted by mammalian cells through exosomes. However, APE1 role in EVs or exosomes is still unknown, especially regarding a putative regulatory function on vesicular small non-coding RNAs. Through dedicated transcriptomic analysis on cellular and vesicular small RNAs of different APE1-depleted cancer cell lines, we found that miRNAs loading into EVs is a regulated process, dependent on APE1, distinctly conveying RNA subsets into vesicles. We identified APE1-dependent secreted miRNAs characterized by enriched sequence motifs and possible binding sites for APE1. In 33 out of 34 APE1-dependent-miRNA precursors, we surprisingly found EXO-motifs and proved that APE1 cooperates with hnRNPA2B1 for the EV-sorting of a subset of miRNAs, including miR-1246, through direct binding to GGAG stretches. Using TCGA-datasets, we showed that these miRNAs identify a signature with high prognostic significance in cancer. In summary, we provided evidence that the ubiquitous DNA-repair enzyme APE1 is part of the EV protein cargo with a novel post-transcriptional role for this ubiquitous DNA-repair enzyme that could explain its role in cancer progression. These findings could open new translational perspectives in cancer biology.
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Affiliation(s)
- Giovanna Mangiapane
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Michela Notarangelo
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Yale University School of Medicine, New Haven, CT, USA
| | - Giulia Canarutto
- Computational Biology, International Centre for Genetic Engineering and Biotechnology, ICGEB, Trieste, Italy
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Fabrizio Fabbiano
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Emiliano Dalla
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Monica Degrassi
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Giulia Antoniali
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Nicolò Gualandi
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Veronica De Sanctis
- Next Generation Sequencing Facility, Department CIBIO, University of Trento, Trento, Italy
| | - Silvano Piazza
- Computational Biology, International Centre for Genetic Engineering and Biotechnology, ICGEB, Trieste, Italy.
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy.
| | - Vito Giuseppe D'Agostino
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy.
| | - Gianluca Tell
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DMED), University of Udine, Udine, Italy.
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Bulygin AA, Syryamina VN, Kuznetsova AA, Novopashina DS, Dzuba SA, Kuznetsov NA. Inner Amino Acid Contacts Are Key Factors of Multistage Structural Rearrangements of DNA and Affect Substrate Specificity of Apurinic/Apyrimidinic Endonuclease APE1. Int J Mol Sci 2023; 24:11474. [PMID: 37511233 PMCID: PMC10380840 DOI: 10.3390/ijms241411474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is one of the most important enzymes in base excision repair. Studies on this enzyme have been conducted for a long time, but some aspects of its activity remain poorly understood. One such question concerns the mechanism of damaged-nucleotide recognition by the enzyme, and the answer could shed light on substrate specificity control in all enzymes of this class. In the present study, by pulsed electron-electron double resonance (DEER, also known as PELDOR) spectroscopy and pre-steady-state kinetic analysis along with wild-type (WT) APE1 from Danio rerio (zAPE1) or three mutants (carrying substitution N253G, A254G, or E260A), we aimed to elucidate the molecular events in the process of damage recognition. The data revealed that the zAPE1 mutant E260A has much higher activity toward DNA substrates containing 5,6-dihydro-2'-deoxyuridine (DHU), 2'-deoxyuridine (dU), alpha-2'-deoxyadenosine (αA), or 1,N6-ethenoadenosine (εA). Examination of conformational changes in DNA clearly revealed multistep DNA rearrangements during the formation of the catalytic complex. These structural rearrangements of DNA are directly associated with the capacity of damaged DNA for enzyme-induced bending and unwinding, which are required for eversion of the damaged nucleotide from the DNA duplex and for its placement into the active site of the enzyme. Taken together, the results experimentally prove the factors that control substrate specificity of the AP endonuclease zAPE1.
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Affiliation(s)
- Anatoly A Bulygin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Victoria N Syryamina
- Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Aleksandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Darya S Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
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Laverde EE, Polyzos AA, Tsegay PP, Shaver M, Hutcheson JD, Balakrishnan L, McMurray CT, Liu Y. Flap Endonuclease 1 Endonucleolytically Processes RNA to Resolve R-Loops through DNA Base Excision Repair. Genes (Basel) 2022; 14:genes14010098. [PMID: 36672839 PMCID: PMC9859040 DOI: 10.3390/genes14010098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/30/2022] Open
Abstract
Flap endonuclease 1 (FEN1) is an essential enzyme that removes RNA primers and base lesions during DNA lagging strand maturation and long-patch base excision repair (BER). It plays a crucial role in maintaining genome stability and integrity. FEN1 is also implicated in RNA processing and biogenesis. A recent study from our group has shown that FEN1 is involved in trinucleotide repeat deletion by processing the RNA strand in R-loops through BER, further suggesting that the enzyme can modulate genome stability by facilitating the resolution of R-loops. However, it remains unknown how FEN1 can process RNA to resolve an R-loop. In this study, we examined the FEN1 cleavage activity on the RNA:DNA hybrid intermediates generated during DNA lagging strand processing and BER in R-loops. We found that both human and yeast FEN1 efficiently cleaved an RNA flap in the intermediates using its endonuclease activity. We further demonstrated that FEN1 was recruited to R-loops in normal human fibroblasts and senataxin-deficient (AOA2) fibroblasts, and its R-loop recruitment was significantly increased by oxidative DNA damage. We showed that FEN1 specifically employed its endonucleolytic cleavage activity to remove the RNA strand in an R-loop during BER. We found that FEN1 coordinated its DNA and RNA endonucleolytic cleavage activity with the 3'-5' exonuclease of APE1 to resolve the R-loop. Our results further suggest that FEN1 employed its unique tracking mechanism to endonucleolytically cleave the RNA strand in an R-loop by coordinating with other BER enzymes and cofactors during BER. Our study provides the first evidence that FEN1 endonucleolytic cleavage can result in the resolution of R-loops via the BER pathway, thereby maintaining genome integrity.
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Affiliation(s)
- Eduardo E. Laverde
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA
| | - Aris A. Polyzos
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Pawlos P. Tsegay
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA
| | - Mohammad Shaver
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Joshua D. Hutcheson
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Lata Balakrishnan
- Department of Biology, Indiana-Purdue University, Indianapolis, IN 46202, USA
| | - Cynthia T. McMurray
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yuan Liu
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
- Correspondence:
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4
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Xue Z, Demple B. Knockout and Inhibition of Ape1: Roles of Ape1 in Base Excision DNA Repair and Modulation of Gene Expression. Antioxidants (Basel) 2022; 11:antiox11091817. [PMID: 36139891 PMCID: PMC9495735 DOI: 10.3390/antiox11091817] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/21/2022] Open
Abstract
Apurinic/apyrimidinic endonuclease 1/redox effector-1 (Ape1/Ref-1) is the major apurinic/apyrimidinic (AP) endonuclease in mammalian cells. It functions mainly in the base excision repair pathway to create a suitable substrate for DNA polymerases. Human Ape1 protein can activate some transcription factors to varying degrees, dependent on its N-terminal, unstructured domain, and some of the cysteines within it, apparently via a redox mechanism in some cases. Many cancer studies also suggest that Ape1 has potential for prognosis in terms of the protein level or intracellular localization. While homozygous disruption of the Ape1 structural gene APEX1 in mice causes embryonic lethality, and most studies in cell culture indicate that the expression of Ape1 is essential, some recent studies reported the isolation of viable APEX1 knockout cells with only mild phenotypes. It has not been established by what mechanism the Ape1-null cell lines cope with the endogenous DNA damage that the enzyme normally handles. We review the enzymatic and other activities of Ape1 and the recent studies of the properties of the APEX1 knockout lines. The APEX1 deletions in CH12F3 and HEK293 FT provide an opportunity to test for possible off-target effects of Ape1 inhibition. For this work, we tested the Ape1 endonuclease inhibitor Compound 3 and the redox inhibitor APX2009. Our results confirmed that both APEX1 knockout cell lines are modestly more sensitive to killing by an alkylating agent than their Ape1-proficient cells. Surprisingly, the knockout lines showed equal sensitivity to direct killing by either inhibitor, despite the lack of the target protein. Moreover, the CH12F3 APEX1 knockout was even more sensitive to Compound 3 than its APEX1+ counterpart. Thus, it appears that both Compound 3 and APX2009 have off-target effects. In cases where this issue may be important, it is advisable that more specific endpoints than cell survival be tested for establishing mechanism.
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Affiliation(s)
- Zhouyiyuan Xue
- Department of Pharmacological Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794-8651, USA
- Molecular and Cellular Biochemistry Program, Stony Brook University, Stony Brook, NY 11794-8651, USA
| | - Bruce Demple
- Department of Pharmacological Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794-8651, USA
- Correspondence: ; Tel.: +1-(631)-444-3978
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Senchurova SI, Syryamina VN, Kuznetsova AA, Novopashina DS, Ishchenko AA, Saparbaev M, Dzuba SA, Fedorova OS, Kuznetsov NA. The mechanism of damage recognition by apurinic/apyrimidinic endonuclease Nfo from Escherichia coli. Biochim Biophys Acta Gen Subj 2022; 1866:130216. [PMID: 35905924 DOI: 10.1016/j.bbagen.2022.130216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/18/2022] [Accepted: 07/18/2022] [Indexed: 12/12/2022]
Abstract
Apurinic/apyrimidinic (AP) endonuclease Nfo from Escherichia coli recognises AP sites in DNA and catalyses phosphodiester bond cleavage on the 5' side of AP sites and some damaged or undamaged nucleotides. Here, the mechanism of target nucleotide recognition by Nfo was analysed by pulsed electron-electron double resonance (PELDOR, also known as DEER) spectroscopy and pre-steady-state kinetic analysis with Förster resonance energy transfer detection of DNA conformational changes during DNA binding. The efficiency of endonucleolytic cleavage of a target nucleotide in model DNA substrates was ranked as (2R,3S)-2-(hydroxymethyl)-3-hydroxytetrahydrofuran [F-site] > 5,6-dihydro-2'-deoxyuridine > α-anomer of 2'-deoxyadenosine >2'-deoxyuridine > undamaged DNA. Real-time conformational changes of DNA during interaction with Nfo revealed an increase of distances between duplex ends during the formation of the initial enzyme-substrate complex. The use of rigid-linker spin-labelled DNA duplexes in DEER measurements indicated that double-helix bending and unwinding by the target nucleotide itself is one of the key factors responsible for indiscriminate recognition of a target nucleotide by Nfo. The results for the first time show that AP endonucleases from different structural families utilise a common strategy of damage recognition, which globally may be integrated with the mechanism of searching for specific sites in DNA by other enzymes.
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Affiliation(s)
- Svetlana I Senchurova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), 8 Prospekt Akad, Lavrentieva, Novosibirsk 630090, Russia
| | - Victoria N Syryamina
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia
| | - Aleksandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), 8 Prospekt Akad, Lavrentieva, Novosibirsk 630090, Russia
| | - Darya S Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), 8 Prospekt Akad, Lavrentieva, Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Murat Saparbaev
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Sergei A Dzuba
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3 Institutskaya Str., Novosibirsk 630090, Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), 8 Prospekt Akad, Lavrentieva, Novosibirsk 630090, Russia.
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences (SB RAS), 8 Prospekt Akad, Lavrentieva, Novosibirsk 630090, Russia; Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Str., Novosibirsk 630090, Russia.
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6
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Bakman AS, Ishchenko AA, Saparbaev M, Fedorova OS, Kuznetsov NA. Pre-steady-state kinetic and mutational insights into mechanisms of endo- and exonuclease DNA processing by mutant forms of human AP endonuclease. Biochim Biophys Acta Gen Subj 2022; 1866:130198. [PMID: 35809816 DOI: 10.1016/j.bbagen.2022.130198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/09/2022] [Accepted: 06/27/2022] [Indexed: 11/19/2022]
Abstract
Human apurinic/apyrimidinic endonuclease APE1 catalyzes endonucleolytic hydrolysis of phosphodiester bonds on the 5' side of structurally unrelated damaged nucleotides in DNA or native nucleotides in RNA. APE1 additionally possesses 3'-5'-exonuclease, 3'-phosphodiesterase, and 3'-phosphatase activities. According to structural data, endo- and exonucleolytic cleavage of DNA is executed in different complexes when the excised residue is everted from the duplex or placed within the intrahelical DNA cavity without nucleotide flipping. In this study, we investigated the functions of residues Arg177, Arg181, Tyr171 and His309 in the APE1 endo- and exonucleolytic reactions. The interaction between residues Arg177 and Met270, which was hypothesized recently to be a switch for endo- and exonucleolytic catalytic mode regulation, was verified by pre-steady-state kinetic analysis of the R177A APE1 mutant. The function of another DNA-binding-site residue, Arg181, was analyzed too; it changed its conformation when enzyme-substrate and enzyme-product complexes were compared. Mutation R181A significantly facilitated the product dissociation stage and only weakly affected DNA-binding affinity. Moreover, R181A reduced the catalytic rate constant severalfold due to a loss of contact with a phosphate group. Finally, the protonation/deprotonation state of residues Tyr171 and His309 in the catalytic reaction was verified by their substitution. Mutations Y171F and H309A inhibited the chemical step of the AP endonucleolytic reaction by several orders of magnitude with retention of capacity for (2R,3S)-2-(hydroxymethyl)-3-hydroxytetrahydrofuran-containing-DNA binding and without changes in the pH dependence profile of AP endonuclease activity, indicating that deprotonation of these residues is likely not important for the catalytic reaction.
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Affiliation(s)
- Artemiy S Bakman
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Murat Saparbaev
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia; Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia.
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7
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Kuznetsova AA, Senchurova SI, Ishchenko AA, Saparbaev M, Fedorova OS, Kuznetsov NA. Common Kinetic Mechanism of Abasic Site Recognition by Structurally Different Apurinic/Apyrimidinic Endonucleases. Int J Mol Sci 2021; 22:ijms22168874. [PMID: 34445579 PMCID: PMC8396254 DOI: 10.3390/ijms22168874] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 02/03/2023] Open
Abstract
Apurinic/apyrimidinic (AP) endonucleases Nfo (Escherichia coli) and APE1 (human) represent two conserved structural families of enzymes that cleave AP-site–containing DNA in base excision repair. Nfo and APE1 have completely different structures of the DNA-binding site, catalytically active amino acid residues and catalytic metal ions. Nonetheless, both enzymes induce DNA bending, AP-site backbone eversion into the active-site pocket and extrusion of the nucleotide located opposite the damage. All these stages may depend on local stability of the DNA duplex near the lesion. Here, we analysed effects of natural nucleotides located opposite a lesion on catalytic-complex formation stages and DNA cleavage efficacy. Several model DNA substrates that contain an AP-site analogue [F-site, i.e., (2R,3S)-2-(hydroxymethyl)-3-hydroxytetrahydrofuran] opposite G, A, T or C were used to monitor real-time conformational changes of the tested enzymes during interaction with DNA using changes in the enzymes’ intrinsic fluorescence intensity mainly caused by Trp fluorescence. The extrusion of the nucleotide located opposite F-site was recorded via fluorescence intensity changes of two base analogues. The catalytic rate constant slightly depended on the opposite-nucleotide nature. Thus, structurally different AP endonucleases Nfo and APE1 utilise a common strategy of damage recognition controlled by enzyme conformational transitions after initial DNA binding.
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Affiliation(s)
- Alexandra A. Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.A.K.); (S.I.S.)
| | - Svetlana I. Senchurova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.A.K.); (S.I.S.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Alexander A. Ishchenko
- Group Mechanisms of DNA Repair and Carcinogenesis, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Gustave Roussy Cancer Campus, Université Paris-Saclay, F-94805 Villejuif, France; (A.A.I.); (M.S.)
| | - Murat Saparbaev
- Group Mechanisms of DNA Repair and Carcinogenesis, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Gustave Roussy Cancer Campus, Université Paris-Saclay, F-94805 Villejuif, France; (A.A.I.); (M.S.)
| | - Olga S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.A.K.); (S.I.S.)
- Correspondence: (O.S.F.); (N.A.K.)
| | - Nikita A. Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.A.K.); (S.I.S.)
- Correspondence: (O.S.F.); (N.A.K.)
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8
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Barchiesi A, Bazzani V, Jabczynska A, Borowski LS, Oeljeklaus S, Warscheid B, Chacinska A, Szczesny RJ, Vascotto C. DNA Repair Protein APE1 Degrades Dysfunctional Abasic mRNA in Mitochondria Affecting Oxidative Phosphorylation. J Mol Biol 2021; 433:167125. [PMID: 34224750 DOI: 10.1016/j.jmb.2021.167125] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 11/19/2022]
Abstract
APE1 is a multifunctional protein which plays a central role in the maintenance of nuclear and mitochondrial genomes repairing DNA lesions caused by oxidative and alkylating agents. In addition, it works as a redox signaling protein regulating gene expression by interacting with many transcriptional factors. Apart from these canonical activities, recent studies have shown that APE1 is also enzymatically active on RNA molecules. The present study unveils for the first time a new role of the mitochondrial form of APE1 protein in the metabolism of RNA in mitochondria. Our data demonstrate that APE1 is associated with mitochondrial messenger RNA and exerts endoribonuclease activity on abasic sites. Loss of APE1 results in the accumulation of damaged mitochondrial mRNA species, determining impairment in protein translation and reduced expression of mitochondrial-encoded proteins, finally leading to less efficient mitochondrial respiration. Altogether, our data demonstrate that APE1 plays an active role in the degradation of the mitochondrial mRNA and has a profound impact on mitochondrial well-being.
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Affiliation(s)
| | | | - Agata Jabczynska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Lukasz S Borowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Faculty of Biology, Institute of Genetics and Biotechnology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Silke Oeljeklaus
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Germany
| | - Agnieszka Chacinska
- Laboratory of Mitochondrial Biogenesis, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland; ReMedy International Research Agenda Unit, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Roman J Szczesny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Carlo Vascotto
- Department of Medicine, University of Udine, 33100 Udine, Italy; Laboratory of Mitochondrial Biogenesis, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland.
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9
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Asada K, Sakaue F, Nagata T, Zhang JC, Yoshida-Tanaka K, Abe A, Nawa M, Nishina K, Yokota T. Short DNA/RNA heteroduplex oligonucleotide interacting proteins are key regulators of target gene silencing. Nucleic Acids Res 2021; 49:4864-4876. [PMID: 33928345 PMCID: PMC8136785 DOI: 10.1093/nar/gkab258] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 03/25/2021] [Accepted: 04/23/2021] [Indexed: 01/31/2023] Open
Abstract
Antisense oligonucleotide (ASO)-based therapy is one of the next-generation therapy, especially targeting neurological disorders. Many cases of ASO-dependent gene expression suppression have been reported. Recently, we developed a tocopherol conjugated DNA/RNA heteroduplex oligonucleotide (Toc-HDO) as a new type of drug. Toc-HDO is more potent, stable, and efficiently taken up by the target tissues compared to the parental ASO. However, the detailed mechanisms of Toc-HDO, including its binding proteins, are unknown. Here, we developed native gel shift assays with fluorescence-labeled nucleic acids samples extracted from mice livers. These assays revealed two Toc-HDO binding proteins, annexin A5 (ANXA5) and carbonic anhydrase 8 (CA8). Later, we identified two more proteins, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) and flap structure-specific endonuclease 1 (FEN1) by data mining. shRNA knockdown studies demonstrated that all four proteins regulated Toc-HDO activity in Hepa1-6, mouse hepatocellular cells. In vitro binding assays and fluorescence polarization assays with purified recombinant proteins characterized the identified proteins and pull-down assays with cell lysates demonstrated the protein binding to the Toc-HDO and ASO in a biological environment. Taken together, our findings provide a brand new molecular biological insight as well as future directions for HDO-based disease therapy.
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Affiliation(s)
- Ken Asada
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Fumika Sakaue
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Tetsuya Nagata
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Ji-chun Zhang
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Kie Yoshida-Tanaka
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Aya Abe
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Makiko Nawa
- Laboratory of Cytometry and Proteome Research, Nanken-Kyoten and Research Core Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Kazutaka Nishina
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takanori Yokota
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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10
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Malfatti MC, Antoniali G, Codrich M, Tell G. Coping with RNA damage with a focus on APE1, a BER enzyme at the crossroad between DNA damage repair and RNA processing/decay. DNA Repair (Amst) 2021; 104:103133. [PMID: 34049077 DOI: 10.1016/j.dnarep.2021.103133] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/06/2021] [Accepted: 05/09/2021] [Indexed: 12/17/2022]
Abstract
Interest in RNA damage as a novel threat associated with several human pathologies is rapidly increasing. Knowledge on damaged RNA recognition, repair, processing and decay is still scanty. Interestingly, in the last few years, more and more evidence put a bridge between DNA damage repair enzymes and the RNA world. The Apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) was firstly identified as a crucial enzyme of the base excision repair (BER) pathway preserving genome stability toward non-distorting DNA lesion-induced damages. Later, an unsuspected role of APE1 in controlling gene expression was discovered and its pivotal involvement in several human pathologies, ranging from tumor progression to neurodegenerative diseases, has emerged. Recent novel findings indicate a role of APE1 in RNA metabolism, particularly in processing activities of damaged (abasic and oxidized) RNA and in the regulation of oncogenic microRNAs (miRNAs). Even though the role of miRNAs in human pathologies is well-known, the mechanisms underlying their quality control are still totally unexplored. A detailed knowledge of damaged RNA decay processes in human cells is crucial in order to understand the molecular processes involved in multiple pathologies. This cutting-edge perspective article will highlight these emerging aspects of damaged RNA processing and decay, focusing the attention on the involvement of APE1 in RNA world.
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Affiliation(s)
- Matilde Clarissa Malfatti
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, Piazzale M. Kolbe 4, 33100 Udine, Italy.
| | - Giulia Antoniali
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, Piazzale M. Kolbe 4, 33100 Udine, Italy.
| | - Marta Codrich
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, Piazzale M. Kolbe 4, 33100 Udine, Italy.
| | - Gianluca Tell
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, Piazzale M. Kolbe 4, 33100 Udine, Italy.
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11
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Kuznetsova AA, Gavrilova AA, Novopashina DS, Fedorova OS, Kuznetsov NA. Mutational and Kinetic Analysis of APE1 Endoribonuclease Activity. Mol Biol 2021; 55:211-224. [PMID: 33948042 PMCID: PMC8083922 DOI: 10.1134/s0026893321020102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/20/2022]
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) participates in the DNA repair system. It is believed that the main biological function of APE1 is Mg2+-dependent hydrolysis of AP-sites in DNA. On the base of structural data, kinetic studies, and mutation analysis, the key stages of APE1 interaction with damaged DNA were established. It has been shown recently that APE1 can act as an endoribonuclease that catalyzes mRNA hydrolysis at certain pyrimidine–purine sites and thus controls the level of certain transcripts. In addition, the presence of Mg2+ ions was shown to be not required for the endoribonuclease activity of APE1, in contrast to the AP-endonuclease activity. This indicates differences in mechanisms of APE1 catalysis on RNA and DNA substrates, but the reasons for these differences remain unclear. Here, the analysis of endoribonuclease hydrolysis of model RNA substrates with wild type APE1 enzyme and its mutant forms Y171F, R177F, R181A, D210N, N212A, T268D, M270A, and D308A, was performed. It was shown that mutation of Asn212, Asp210, and Tyr171 residues leads to the decrease of AP-endonuclease activity while endoribonuclease activity is retained. Also, T268D and M270A APE1 mutants lose specificity to pyrimidine–purine sequences. R177F and R181A did not show a significant decrease in enzyme activity, whereas D308A demonstrated a decrease of endoribonuclease activity.
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Affiliation(s)
- A A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - A A Gavrilova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia.,Novosibirsk National Research State University, 630090 Novosibirsk, Russia
| | - D S Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - O S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - N A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
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12
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Vågbø CB, Slupphaug G. RNA in DNA repair. DNA Repair (Amst) 2020; 95:102927. [DOI: 10.1016/j.dnarep.2020.102927] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/22/2022]
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13
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Davletgildeeva AT, Kuznetsova AA, Fedorova OS, Kuznetsov NA. Activity of Human Apurinic/Apyrimidinic Endonuclease APE1 Toward Damaged DNA and Native RNA With Non-canonical Structures. Front Cell Dev Biol 2020; 8:590848. [PMID: 33195255 PMCID: PMC7662432 DOI: 10.3389/fcell.2020.590848] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/30/2020] [Indexed: 01/02/2023] Open
Abstract
The primary role of apurinic/apyrimidinic (AP) endonuclease APE1 in human cells is the cleavage of the sugar phosphate backbone 5' to an AP site in DNA to produce a single-strand break with a 5'-deoxyribose phosphate and 3'-hydroxyl end groups. APE1 can also recognize and incise some damaged or modified nucleotides and possesses some minor activities: 3'-5' exonuclease, 3'-phosphodiesterase, 3'-phosphatase, and RNase H. A molecular explanation for the discrimination of structurally different substrates by the single active site of the enzyme remains elusive. Here, we report a mechanism of target nucleotide recognition by APE1 as revealed by the results of an analysis of the APE1 process involving damaged DNA and native RNA substrates with non-canonical structures. The mechanism responsible for substrate specificity proved to be directly related to the ability of a target nucleotide to get into the active site of APE1 in response to an enzyme-induced DNA distortion.
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Affiliation(s)
- Anastasia T Davletgildeeva
- Institute of Chemical Biology and Fundamental Medicine of the SB RAS, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Alexandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine of the SB RAS, Novosibirsk, Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine of the SB RAS, Novosibirsk, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine of the SB RAS, Novosibirsk, Russia
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14
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The role of active-site amino acid residues in the cleavage of DNA and RNA substrates by human apurinic/apyrimidinic endonuclease APE1. Biochim Biophys Acta Gen Subj 2020; 1864:129718. [PMID: 32858086 DOI: 10.1016/j.bbagen.2020.129718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/10/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Human apurinic/apyrimidinic endonuclease APE1 is one of participants of the DNA base excision repair pathway. APE1 processes AP-sites and many other types of DNA damage via hydrolysis of the phosphodiester bond on the 5' side of the lesion. APE1 also acts as an endoribonuclease, i.e., can cleave undamaged RNA. METHODS Using pre-steady-state kinetic analysis we examined the role of certain catalytically important amino acids in APE1 enzymatic pathway and described their involvement in the mechanism of the target nucleotide recognition. RESULTS Comparative analysis of the cleavage efficiency of damaged DNAs containing an abasic site, 5,6-dihydrouridine, or α-anomer of adenosine as well as 3'-5'-exonuclease degradation of undamaged DNA and endonuclease hydrolysis of RNA substrates by mutant APE1 enzymes containing a substitution of an active-site amino acid residue (D210N, N212A, T268D, M270A, or D308A) was performed. Detailed pre-steady-state kinetics of conformational changes of the enzyme and of DNA substrate molecules during recognition and cleavage of the abasic site were studied. CONCLUSIONS It was revealed that substitution T268D significantly disturbed initial DNA binding, whereas Asn212 is critical for the DNA-bending stage and catalysis. Substitution D210N increased the binding efficacy and blocked the catalytic reaction, but D308A decreased the binding efficacy owing to disruption of Mg2+ coordination. Finally, the substitution of Met270 also destabilized the enzyme-substrate complex but did not affect the catalytic reaction. SIGNIFICANCE It was found that the tested substitutions of the active-site amino acid residues affected different stages of the complex formation process as well as the catalytic reaction.
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15
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Alekseeva IV, Bakman AS, Vorobjev YN, Fedorova OS, Kuznetsov NA. Role of Ionizing Amino Acid Residues in the Process of DNA Binding by Human AP Endonuclease 1 and in Its Catalysis. J Phys Chem B 2019; 123:9546-9556. [PMID: 31633353 DOI: 10.1021/acs.jpcb.9b07150] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the repair of the damage to bases, human apurinic/apyrimidinic (AP) endonuclease 1 (APE1) is a key participant via the DNA base excision repair pathway. APE1 cleaves AP sites in DNA, which are potentially cytotoxic and highly mutagenic if left unrepaired. According to existing structural data, this enzyme's active site contains many polar amino acid residues, which form extensive contacts with a DNA substrate. A few alternative catalytic mechanisms of the phosphodiester bond hydrolysis by APE1 have been reported. Here, the kinetics of conformational changes of the enzyme and of DNA substrate molecules were studied during the recognition and cleavage of the abasic site in the pH range from 5.5 to 9.0 using stopped-flow fluorescence techniques. The activity of APE1 increased with an increase in pH because of acceleration of the rates of catalytic complex formation and of the catalytic reaction. Molecular dynamics simulation uncovered a significant increase in the pKa of His-309 located in the active site of the enzyme. This finding revealed that the observed enhancement of enzymatic activity with pH could be associated with deprotonation of not only Tyr-171 but also His-309. The obtained data allowed us to hypothesize that the ionized state of these residues could be a molecular switch between the alternative catalytic mechanisms, which involve different functionalities of these residues throughout the reaction.
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Affiliation(s)
- Irina V Alekseeva
- Institute of Chemical Biology and Fundamental Medicine , Novosibirsk 630090 , Russia
| | - Artemiy S Bakman
- Institute of Chemical Biology and Fundamental Medicine , Novosibirsk 630090 , Russia
| | - Yury N Vorobjev
- Institute of Chemical Biology and Fundamental Medicine , Novosibirsk 630090 , Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine , Novosibirsk 630090 , Russia.,Department of Natural Sciences , Novosibirsk State University , Novosibirsk 630090 , Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine , Novosibirsk 630090 , Russia.,Department of Natural Sciences , Novosibirsk State University , Novosibirsk 630090 , Russia
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16
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Sun Y, Feng Y, Zhang G, Xu Y. The endonuclease APE1 processes miR-92b formation, thereby regulating expression of the tumor suppressor LDLR in cervical cancer cells. Ther Adv Med Oncol 2019; 11:1758835919855859. [PMID: 31320936 PMCID: PMC6624912 DOI: 10.1177/1758835919855859] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 05/01/2019] [Indexed: 12/25/2022] Open
Abstract
Background The molecular mechanisms underlying cervical cancer require elucidation to identify novel therapeutic targets. Apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) is a multifunctional apurinic/apyrimidinic (AP) endonuclease that influences the transcription of many cancer-related genes via microRNome regulation. Herein, we examine the role of miR-92b-3p (hereinafter miR-92b), whose processing may be regulated by APE1, in cervical cancer progression. Methods APE1's processing of miR-92b from its pri-miR form was measured by a quantitative reverse transcription polymerase chain reaction (qRT-PCR)-based ratio. APE1's endonuclease activity was measured with AP-site incision assays. APE1-DROSHA interaction was studied with immunofluorescence, confocal and proximity ligation analyses. The miR-92b's targeting of low-density lipoprotein receptor (LDLR) was investigated with luciferase reporter assays. The miR-92b mimics and shRNA-based miR-92b silencing, as well as LDLR overexpression and short interfering RNA (siRNA)-based LDLR silencing, were employed in CaSki and SiHa cervical cancer cells. Cell proliferation and chemosensitivity to paclitaxel and cisplatin were assayed. Cell-cycle progression and apoptosis were assessed by flow cytometry. Tumor growth was studied in a murine xenograft model. Results APE1's endonuclease activity, via association with the DROSHA-processing complex, is necessary for processing mature miR-92b, thereby regulating expression of miR-92b's direct target LDLR. The miR-92b promotes cell proliferation in vitro and in vivo, promotes cell-cycle progression, and reduces apoptosis and chemosensitivity. LDLR silencing recapitulated miR-92b's transformative effects, while LDLR overexpression rescued these effects. Conclusions APE1 enhances miR-92b processing, thereby suppressing LDLR expression and enhancing cervical carcinoma progression. Our identification of the novel APE1-miR-92b-LDLR axis improves our understanding of the complex pathogenesis of cervical carcinoma and reveals a novel therapeutic strategy for combating this disease.
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Affiliation(s)
- Yi Sun
- Department of Clinical Laboratory Medicine, the First People's Hospital of Yunnan Province, No. 157, Jinbi Road, Kunming, Yunnan Province, China
| | - Yun Feng
- Department of Reproductive Gynecology, The First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Guiqian Zhang
- Department of Clinical Laboratory Medicine, The First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Ya Xu
- Department of Clinical Laboratory Medicine, The First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
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17
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Frossi B, Antoniali G, Yu K, Akhtar N, Kaplan MH, Kelley MR, Tell G, Pucillo CEM. Endonuclease and redox activities of human apurinic/apyrimidinic endonuclease 1 have distinctive and essential functions in IgA class switch recombination. J Biol Chem 2019; 294:5198-5207. [PMID: 30705092 DOI: 10.1074/jbc.ra118.006601] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/28/2019] [Indexed: 11/06/2022] Open
Abstract
The base excision repair (BER) pathway is an important DNA repair pathway and is essential for immune responses. In fact, it regulates both the antigen-stimulated somatic hypermutation (SHM) process and plays a central function in the process of class switch recombination (CSR). For both processes, a central role for apurinic/apyrimidinic endonuclease 1 (APE1) has been demonstrated. APE1 acts also as a master regulator of gene expression through its redox activity. APE1's redox activity stimulates the DNA-binding activity of several transcription factors, including NF-κB and a few others involved in inflammation and in immune responses. Therefore, it is possible that APE1 has a role in regulating the CSR through its function as a redox coactivator. The present study was undertaken to address this question. Using the CSR-competent mouse B-cell line CH12F3 and a combination of specific inhibitors of APE1's redox (APX3330) and repair (compound 3) activities, APE1-deficient or -reconstituted cell lines expressing redox-deficient or endonuclease-deficient proteins, and APX3330-treated mice, we determined the contributions of both endonuclease and redox functions of APE1 in CSR. We found that APE1's endonuclease activity is essential for IgA-class switch recombination. We provide evidence that the redox function of APE1 appears to play a role in regulating CSR through the interleukin-6 signaling pathway and in proper IgA expression. Our results shed light on APE1's redox function in the control of cancer growth through modulation of the IgA CSR process.
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Affiliation(s)
- Barbara Frossi
- From the Laboratory of Immunology, Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Giulia Antoniali
- the Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Kefei Yu
- the Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824, and
| | - Nahid Akhtar
- the Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Mark H Kaplan
- the Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Mark R Kelley
- the Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Gianluca Tell
- the Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy,
| | - Carlo E M Pucillo
- From the Laboratory of Immunology, Department of Medicine, University of Udine, 33100 Udine, Italy,
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18
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Antoniali G, Serra F, Lirussi L, Tanaka M, D'Ambrosio C, Zhang S, Radovic S, Dalla E, Ciani Y, Scaloni A, Li M, Piazza S, Tell G. Mammalian APE1 controls miRNA processing and its interactome is linked to cancer RNA metabolism. Nat Commun 2017; 8:797. [PMID: 28986522 PMCID: PMC5630600 DOI: 10.1038/s41467-017-00842-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 07/28/2017] [Indexed: 01/31/2023] Open
Abstract
Mammalian apurinic/apyrimidinic endonuclease 1 is a DNA repair enzyme involved in genome stability and expression of genes involved in oxidative stress responses, tumor progression and chemoresistance. However, the molecular mechanisms underlying the role of apurinic/apyrimidinic endonuclease 1 in these processes are still unclear. Recent findings point to a novel role of apurinic/apyrimidinic endonuclease 1 in RNA metabolism. Through the characterization of the interactomes of apurinic/apyrimidinic endonuclease 1 with RNA and other proteins, we demonstrate here a role for apurinic/apyrimidinic endonuclease 1 in pri-miRNA processing and stability via association with the DROSHA-processing complex during genotoxic stress. We also show that endonuclease activity of apurinic/apyrimidinic endonuclease 1 is required for the processing of miR-221/222 in regulating expression of the tumor suppressor PTEN. Analysis of a cohort of different cancers supports the relevance of our findings for tumor biology. We also show that apurinic/apyrimidinic endonuclease 1 participates in RNA-interactomes and protein-interactomes involved in cancer development, thus indicating an unsuspected post-transcriptional effect on cancer genes. APE1 plays an important role in the cellular response to oxidative stress, and mutations are linked to tumor progression and chemoresistance. Here, the authors characterize the interactions of APE1 with RNA and demonstrate a role in microRNA processing.
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Affiliation(s)
- Giulia Antoniali
- Department of Medicine, Laboratory of Molecular Biology and DNA repair, University of Udine, p.le M. Kolbe 4, Udine, 33100, Italy
| | - Fabrizio Serra
- Department of Medicine, Laboratory of Molecular Biology and DNA repair, University of Udine, p.le M. Kolbe 4, Udine, 33100, Italy.,Clinical and Experimental Onco-Hematology Unit, Centro di Riferimento Oncologico, I.R.C.C.S., via Franco Gallini 2, Aviano (PN), 33081, Italy
| | - Lisa Lirussi
- Department of Medicine, Laboratory of Molecular Biology and DNA repair, University of Udine, p.le M. Kolbe 4, Udine, 33100, Italy.,Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, Sykehusveien 27, Nordbyhagen, 1474, Norway
| | - Mikiei Tanaka
- Laboratory of Biochemistry, National Heart Lung and Blood Institute, National Institutes of Health, 50 South Drive, MSC-8012, Bethesda, MD, 20892-8012, USA
| | - Chiara D'Ambrosio
- Proteomics and Mass Spectrometry Laboratory, Institute for the Animal Production System in the Mediterranean Environment (ISPAAM) National Research Council (CNR) of Italy, via Argine 1085, Naples, 80147, Italy
| | - Shiheng Zhang
- Cancer Center of Daping Hospital, Third Military Medical University, Chongqing, 400042, China
| | | | - Emiliano Dalla
- Laboratorio Nazionale CIB, Area Science Park Padriciano, Trieste, 34149, Italy
| | - Yari Ciani
- Laboratorio Nazionale CIB, Area Science Park Padriciano, Trieste, 34149, Italy
| | - Andrea Scaloni
- Proteomics and Mass Spectrometry Laboratory, Institute for the Animal Production System in the Mediterranean Environment (ISPAAM) National Research Council (CNR) of Italy, via Argine 1085, Naples, 80147, Italy
| | - Mengxia Li
- Cancer Center of Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
| | - Silvano Piazza
- Laboratorio Nazionale CIB, Area Science Park Padriciano, Trieste, 34149, Italy. .,Bioinformatics Core Facility, Centre for Integrative Biology, CIBIO, University of Trento, via Sommarive 18, Povo, Trento, TN, 38123, Italy.
| | - Gianluca Tell
- Department of Medicine, Laboratory of Molecular Biology and DNA repair, University of Udine, p.le M. Kolbe 4, Udine, 33100, Italy.
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19
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Cesselli D, Aleksova A, Sponga S, Cervellin C, Di Loreto C, Tell G, Beltrami AP. Cardiac Cell Senescence and Redox Signaling. Front Cardiovasc Med 2017; 4:38. [PMID: 28612009 PMCID: PMC5447053 DOI: 10.3389/fcvm.2017.00038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/10/2017] [Indexed: 12/12/2022] Open
Abstract
Aging is characterized by a progressive loss of the ability of the organism to cope with stressors and to repair tissue damage. As a result, chronic diseases, including cardiovascular disease, increase their prevalence with aging, underlining the existence of common mechanisms that lead to frailty and age-related diseases. In this frame, the progressive decline of the homeostatic and reparative function of primitive cells has been hypothesized to play a major role in the evolution of cardiac pathology to heart failure. Although initially it was believed that reactive oxygen species (ROS) were produced in an unregulated manner as a byproduct of cellular metabolism, causing macromolecular damage and aging, accumulating evidence indicate the major role played by redox signaling in physiology. Aim of this review is to critically revise evidence linking ROS to cell senescence and aging and to provide evidence of the primary role played by redox signaling, with a particular emphasis on the multifunctional protein APE1/Ref in stem cell biology. Finally, we will discuss evidence supporting the role of redox signaling in cardiovascular cells.
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Affiliation(s)
| | - Aneta Aleksova
- Cardiovascular Department, Azienda Sanitaria Universitaria Integrata di Trieste, University of Trieste, Trieste, Italy
| | - Sandro Sponga
- Cardiothoracic Surgery, Azienda Sanitaria Universitaria Integrata di Udine, Udine, Italy
| | | | | | - Gianluca Tell
- Department of Medicine, University of Udine, Udine, Italy
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20
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Laev SS, Salakhutdinov NF, Lavrik OI. Inhibitors of nuclease and redox activity of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1). Bioorg Med Chem 2017; 25:2531-2544. [PMID: 28161249 DOI: 10.1016/j.bmc.2017.01.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 01/15/2023]
Abstract
Human apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional protein which is essential in the base excision repair (BER) pathway of DNA lesions caused by oxidation and alkylation. This protein hydrolyzes DNA adjacent to the 5'-end of an apurinic/apyrimidinic (AP) site to produce a nick with a 3'-hydroxyl group and a 5'-deoxyribose phosphate moiety or activates the DNA-binding activity of certain transcription factors through its redox function. Studies have indicated a role for APE1/Ref-1 in the pathogenesis of cancer and in resistance to DNA-interactive drugs. Thus, this protein has potential as a target in cancer treatment. As a result, major efforts have been directed to identify small molecule inhibitors against APE1/Ref-1 activities. These agents have the potential to become anticancer drugs. The aim of this review is to present recent progress in studies of all published small molecule APE1/Ref-1 inhibitors. The structures and activities of APE1/Ref-1 inhibitors, that target both DNA repair and redox activities, are presented and discussed. To date, there is an urgent need for further development of the design and synthesis of APE1/Ref-1 inhibitors due to high importance of this protein target.
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Affiliation(s)
- Sergey S Laev
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation.
| | - Nariman F Salakhutdinov
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation
| | - Olga I Lavrik
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation; Novosibirsk Institute of Chemical Biology and Fundamental Medicine, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 8, Novosibirsk 630090, Russian Federation
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21
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Dyrkheeva NS, Lebedeva NA, Lavrik OI. AP Endonuclease 1 as a Key Enzyme in Repair of Apurinic/Apyrimidinic Sites. BIOCHEMISTRY (MOSCOW) 2017; 81:951-67. [PMID: 27682167 DOI: 10.1134/s0006297916090042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) is one of the key participants in the DNA base excision repair system. APE1 hydrolyzes DNA adjacent to the 5'-end of an apurinic/apyrimidinic (AP) site to produce a nick with a 3'-hydroxyl group and a 5'-deoxyribose phosphate moiety. APE1 exhibits 3'-phosphodiesterase, 3'-5'-exonuclease, and 3'-phosphatase activities. APE1 was also identified as a redox factor (Ref-1). In this review, data on the role of APE1 in the DNA repair process and in other metabolic processes occurring in cells are analyzed as well as the interaction of this enzyme with DNA and other proteins participating in the repair system.
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Affiliation(s)
- N S Dyrkheeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
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22
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Virus world as an evolutionary network of viruses and capsidless selfish elements. Microbiol Mol Biol Rev 2015; 78:278-303. [PMID: 24847023 DOI: 10.1128/mmbr.00049-13] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Viruses were defined as one of the two principal types of organisms in the biosphere, namely, as capsid-encoding organisms in contrast to ribosome-encoding organisms, i.e., all cellular life forms. Structurally similar, apparently homologous capsids are present in a huge variety of icosahedral viruses that infect bacteria, archaea, and eukaryotes. These findings prompted the concept of the capsid as the virus "self" that defines the identity of deep, ancient viral lineages. However, several other widespread viral "hallmark genes" encode key components of the viral replication apparatus (such as polymerases and helicases) and combine with different capsid proteins, given the inherently modular character of viral evolution. Furthermore, diverse, widespread, capsidless selfish genetic elements, such as plasmids and various types of transposons, share hallmark genes with viruses. Viruses appear to have evolved from capsidless selfish elements, and vice versa, on multiple occasions during evolution. At the earliest, precellular stage of life's evolution, capsidless genetic parasites most likely emerged first and subsequently gave rise to different classes of viruses. In this review, we develop the concept of a greater virus world which forms an evolutionary network that is held together by shared conserved genes and includes both bona fide capsid-encoding viruses and different classes of capsidless replicons. Theoretical studies indicate that selfish replicons (genetic parasites) inevitably emerge in any sufficiently complex evolving ensemble of replicators. Therefore, the key signature of the greater virus world is not the presence of a capsid but rather genetic, informational parasitism itself, i.e., various degrees of reliance on the information processing systems of the host.
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23
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He H, Chen Q, Georgiadis MM. High-resolution crystal structures reveal plasticity in the metal binding site of apurinic/apyrimidinic endonuclease I. Biochemistry 2014; 53:6520-9. [PMID: 25251148 PMCID: PMC4204877 DOI: 10.1021/bi500676p] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Apurinic/apyrimidinic
endonuclease I (APE1) is an essential base
excision repair enzyme that catalyzes a Mg2+-dependent
reaction in which the phosphodiester backbone is cleaved 5′
of an abasic site in duplex DNA. This reaction has been proposed to
involve either one or two metal ions bound to the active site. In
the present study, we report crystal structures of Mg2+, Mn2+, and apo-APE1 determined at 1.4, 2.2, and 1.65
Å, respectively, representing two of the highest resolution structures
yet reported for APE1. In our structures, a single well-ordered Mn2+ ion was observed coordinated by D70 and E96; the Mg2+ site exhibited disorder modeled as two closely positioned
sites coordinated by D70 and E96 or E96 alone. Direct metal binding
analysis of wild-type, D70A, and E96A APE1, as assessed by differential
scanning fluorimetry, indicated a role for D70 and E96 in binding
of Mg2+ or Mn2+ to APE1. Consistent with the
disorder exhibited by Mg2+ bound to the active site, two
different conformations of E96 were observed coordinated to Mg2+. A third conformation for E96 in the apo structure is similar
to that observed in the APE1–DNA–Mg2+ complex
structure. Thus, binding of Mg2+ in three different positions
within the active site of APE1 in these crystal structures corresponds
directly with three different conformations of E96. Taken together,
our results are consistent with the initial capture of metal by D70
and E96 and repositioning of Mg2+ facilitated by the structural
plasticity of E96 in the active site.
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Affiliation(s)
- Hongzhen He
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
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Wang Z, Ayoub E, Mazouzi A, Grin I, Ishchenko AA, Fan J, Yang X, Harihar T, Saparbaev M, Ramotar D. Functional variants of human APE1 rescue the DNA repair defects of the yeast AP endonuclease/3'-diesterase-deficient strain. DNA Repair (Amst) 2014; 22:53-66. [PMID: 25108836 DOI: 10.1016/j.dnarep.2014.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 07/02/2014] [Accepted: 07/17/2014] [Indexed: 12/22/2022]
Abstract
Human APE1 is an essential enzyme performing functions in DNA repair and transcription. It possesses four distinct repair activities acting on a variety of base and sugar derived DNA lesions. APE1 has seven cysteine residues and Cys65, and to a lesser extent Cys93 and Cys99, is uniquely involved in maintaining a subset of transcription factors in the reduced and active state. Four of the cysteines Cys93, 99, 208 and 310 of APE1 are located proximal to its active site residues Glu96, Asp210 and His309 involved in processing damaged DNA, raising the possibility that missense mutation of these cysteines could alter the enzyme DNA repair functions. An earlier report documented that serine substitution of the individual cysteine residues did not affect APE1 ability to cleave an abasic site oligonucleotide substrate in vitro, except for Cys99Ser, although any consequences of these variants in the repair of in vivo DNA lesions were not tested. Herein, we mutated all seven cysteines of APE1, either singly or in combination, to alanine and show that none of the resulting variants interfered with the enzyme DNA repair functions. Cross-specie complementation analysis reveals that these APE1 cysteine variants fully rescued the yeast DNA repair deficient strain YW778, lacking AP endonucleases and 3'-diesterases, from toxicities caused by DNA damaging agents. Moreover, the elevated spontaneous mutations arising in strain YW778 from the lack of the DNA repair activities were completely suppressed by the APE1 cysteine variants. These findings suggest that the cysteine residues of APE1 are unlikely to play a role in the DNA repair functions of the enzyme in vivo. We also examine other APE1 missense mutations and provide the first evidence that the variant Asp308Ala with normal AP endonuclease, but devoid of 3'→5' exonuclease, displays hypersensitivity to the anticancer drug bleomycin, and not to other agents, suggesting that it has a defect in processing unique DNA lesions. Molecular modeling reveals that Asp308Ala cannot make proper contact with Mg(2+) and may alter the enzyme ability to cleave or disassociate from specific DNA lesions.
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Affiliation(s)
- Zhiqiang Wang
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4
| | - Emily Ayoub
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4
| | - Abdelghani Mazouzi
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4
| | - Inga Grin
- Groupe Réparation de l'ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave-Roussy Cancer Center, F-94805 Villejuif Cedex, France; SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave. , Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Groupe Réparation de l'ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave-Roussy Cancer Center, F-94805 Villejuif Cedex, France
| | - Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
| | - Xiaoming Yang
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4
| | - Taramatti Harihar
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4
| | - Murat Saparbaev
- Groupe Réparation de l'ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave-Roussy Cancer Center, F-94805 Villejuif Cedex, France
| | - Dindial Ramotar
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal 5415 Boul. de l' Assomption, Montréal, Québec, Canada H1T 2M4.
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25
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De Summa S, Pinto R, Sambiasi D, Petriella D, Paradiso V, Paradiso A, Tommasi S. BRCAness: a deeper insight into basal-like breast tumors. Ann Oncol 2014; 24 Suppl 8:viii13-viii21. [PMID: 24131964 DOI: 10.1093/annonc/mdt306] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The molecular scenario of breast cancer has become more complex in the last few years. Distinguishing between BRCA-associated, sporadic, HER2-enriched and triple-negative tumors is not sufficient to allow effective clinical management. Basal-like breast cancer, a subtype of triple-negative breast cancer, differs from others grouped under this heading. Commonalities between BRCA-related tumors and basal-like breast cancers (BRCAness phenotype) are highly relevant to ongoing clinical trials, in particular those investigating targeted therapies (e.g. PARP inhibitors) in sporadic breast tumors. The 'gold standard' to identify basal-like phenotype is DNA microarray, but integrated results could provide a panel of biomarkers helpful in identifying 'BRCAness' tumors (e.g. copy number aberrations, abnormal protein localization and altered transcriptional levels) and other molecular targets, such as APE1,the inhibition of which is emerging as an attractive breast cancer treatment in certain therapeutic settings.
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Affiliation(s)
- S De Summa
- NCRC Istituto Tumori 'Giovanni Paolo II', Bari, Italy
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26
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De Summa S, Pinto R, Pilato B, Sambiasi D, Porcelli L, Guida G, Mattioli E, Paradiso A, Merla G, Micale L, De Nittis P, Tommasi S. Expression of base excision repair key factors and miR17 in familial and sporadic breast cancer. Cell Death Dis 2014; 5:e1076. [PMID: 24556691 PMCID: PMC3944247 DOI: 10.1038/cddis.2014.30] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/24/2013] [Accepted: 01/02/2014] [Indexed: 01/05/2023]
Abstract
Understanding of BRCA1/2 interaction with the base excision repair (BER) pathway could improve therapy based on ‘synthetic lethality', whose effectiveness is based on homologous recombination deficiency in cells lacking functional BRCA genes. However, poly (ADP-ribose) polymerase (PARP) inhibitors failed in some patients and for this reason we explored BER key enzyme expression. In this study, the expression of BER enzymes (redox factor 1/apurinic-apyrimidinic endonuclease 1 (REF1/APEX1), NTH endonuclease III-like 1 (NTHL1), 8-oxoguanine DNA glycosylase (OGG1), PARP1) and of the scaffold protein XRCC1 (X-ray repair complementing defective repair in Chinese hamster cells 1) were investigated in familial (BRCA-related and not) and sporadic breast cancer cases. Furthermore, miR17 expression was measured because of its role in the epigenetic regulation of BRCA1. Gene expression was evaluated in BRCA1-mutated cell lines, SUM149PT and SUM1315MO2, and in a BRCA1-proficient triple-negative MDA-MB-231 cell line. A cohort of 27 familial and 16 sporadic breast cancer patients was then examined to confirm results obtained from the cell line model. APEX1/REF1 was found to be upregulated in familial BRCA-wild-type and sporadic cases, indicating this enzyme as a potential therapeutic target. Furthermore, XRCC1 was overexpressed in BRCAX patients; consequently, we suggest to test the effectiveness of inhibitors targeting two different BER components in preclinical studies. XRCC1, which is also involved in the non-homologous end-joining pathway, was found to be downregulated in BRCA2-related patients concurrently with no change in PARP1 expression. Interestingly, no difference in PARP1 and miR17 expression was found in BRCA-related and sporadic breast cancer cases. PARP1 and miR17 could therefore be further investigated as molecular biomarkers of ‘BRCAness' phenotype, indicating patients which could really benefit from PARP inhibitor therapies.
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Affiliation(s)
- S De Summa
- Molecular Genetics Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - R Pinto
- Molecular Genetics Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - B Pilato
- Molecular Genetics Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - D Sambiasi
- Molecular Genetics Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - L Porcelli
- Preclinical and Clinical Pharmacology Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - G Guida
- Department of Medical Biochemistry, Medical Biology and Medical Physics, School of Medicine, University of Bari, Bari, Italy
| | - E Mattioli
- Anatomopathology Unit, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - A Paradiso
- Experimental Medical Oncology Unit, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - G Merla
- Medical Genetics Unit, IRCCS Casa Sollievo delle Sofferenza, San Giovanni Rotondo, Italy
| | - L Micale
- Medical Genetics Unit, IRCCS Casa Sollievo delle Sofferenza, San Giovanni Rotondo, Italy
| | - P De Nittis
- Medical Genetics Unit, IRCCS Casa Sollievo delle Sofferenza, San Giovanni Rotondo, Italy
| | - S Tommasi
- Molecular Genetics Laboratory, National Cancer Research Centre, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
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27
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Abstract
SIGNIFICANCE Human apurinic/apyrimidinic endonuclease 1 (APE1, also known as REF-1) was isolated based on its ability to cleave at AP sites in DNA or activate the DNA binding activity of certain transcription factors. We review herein topics related to this multi-functional DNA repair and stress-response protein. RECENT ADVANCES APE1 displays homology to Escherichia coli exonuclease III and is a member of the divalent metal-dependent α/β fold-containing phosphoesterase superfamily of enzymes. APE1 has acquired distinct active site and loop elements that dictate substrate selectivity, and a unique N-terminus which at minimum imparts nuclear targeting and interaction specificity. Additional activities ascribed to APE1 include 3'-5' exonuclease, 3'-repair diesterase, nucleotide incision repair, damaged or site-specific RNA cleavage, and multiple transcription regulatory roles. CRITICAL ISSUES APE1 is essential for mouse embryogenesis and contributes to cell viability in a genetic background-dependent manner. Haploinsufficient APE1(+/-) mice exhibit reduced survival, increased cancer formation, and cellular/tissue hyper-sensitivity to oxidative stress, supporting the notion that impaired APE1 function associates with disease susceptibility. Although abnormal APE1 expression/localization has been seen in cancer and neuropathologies, and impaired-function variants have been described, a causal link between an APE1 defect and human disease remains elusive. FUTURE DIRECTIONS Ongoing efforts aim at delineating the biological role(s) of the different APE1 activities, as well as the regulatory mechanisms for its intra-cellular distribution and participation in diverse molecular pathways. The determination of whether APE1 defects contribute to human disease, particularly pathologies that involve oxidative stress, and whether APE1 small-molecule regulators have clinical utility, is central to future investigations.
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Affiliation(s)
- Mengxia Li
- Intramural Research Program, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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28
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Scott TL, Rangaswamy S, Wicker CA, Izumi T. Repair of oxidative DNA damage and cancer: recent progress in DNA base excision repair. Antioxid Redox Signal 2014; 20:708-26. [PMID: 23901781 PMCID: PMC3960848 DOI: 10.1089/ars.2013.5529] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) are generated by exogenous and environmental genotoxins, but also arise from mitochondria as byproducts of respiration in the body. ROS generate DNA damage of which pathological consequence, including cancer is well established. Research efforts are intense to understand the mechanism of DNA base excision repair, the primary mechanism to protect cells from genotoxicity caused by ROS. RECENT ADVANCES In addition to the notion that oxidative DNA damage causes transformation of cells, recent studies have revealed how the mitochondrial deficiencies and ROS generation alter cell growth during the cancer transformation. CRITICAL ISSUES The emphasis of this review is to highlight the importance of the cellular response to oxidative DNA damage during carcinogenesis. Oxidative DNA damage, including 7,8-dihydro-8-oxoguanine, play an important role during the cellular transformation. It is also becoming apparent that the unusual activity and subcellular distribution of apurinic/apyrimidinic endonuclease 1, an essential DNA repair factor/redox sensor, affect cancer malignancy by increasing cellular resistance to oxidative stress and by positively influencing cell proliferation. FUTURE DIRECTIONS Technological advancement in cancer cell biology and genetics has enabled us to monitor the detailed DNA repair activities in the microenvironment. Precise understanding of the intracellular activities of DNA repair proteins for oxidative DNA damage should provide help in understanding how mitochondria, ROS, DNA damage, and repair influence cancer transformation.
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Affiliation(s)
- Timothy L Scott
- Graduate Center for Toxicology, University of Kentucky , Lexington, Kentucky
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29
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Antoniali G, Lirussi L, Poletto M, Tell G. Emerging roles of the nucleolus in regulating the DNA damage response: the noncanonical DNA repair enzyme APE1/Ref-1 as a paradigmatical example. Antioxid Redox Signal 2014; 20:621-39. [PMID: 23879289 PMCID: PMC3901381 DOI: 10.1089/ars.2013.5491] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 07/22/2013] [Indexed: 12/25/2022]
Abstract
SIGNIFICANCE An emerging concept in DNA repair mechanisms is the evidence that some key enzymes, besides their role in the maintenance of genome stability, display also unexpected noncanonical functions associated with RNA metabolism in specific subcellular districts (e.g., nucleoli). During the evolution of these key enzymes, the acquisition of unfolded domains significantly amplified the possibility to interact with different partners and substrates, possibly explaining their phylogenetic gain of functions. RECENT ADVANCES After nucleolar stress or DNA damage, many DNA repair proteins can freely relocalize from nucleoli to the nucleoplasm. This process may represent a surveillance mechanism to monitor the synthesis and correct assembly of ribosomal units affecting cell cycle progression or inducing p53-mediated apoptosis or senescence. CRITICAL ISSUES A paradigm for this kind of regulation is represented by some enzymes of the DNA base excision repair (BER) pathway, such as apurinic/apyrimidinic endonuclease 1 (APE1). In this review, the role of the nucleolus and the noncanonical functions of the APE1 protein are discussed in light of their possible implications in human pathologies. FUTURE DIRECTIONS A productive cross-talk between DNA repair enzymes and proteins involved in RNA metabolism seems reasonable as the nucleolus is emerging as a dynamic functional hub that coordinates cell growth arrest and DNA repair mechanisms. These findings will drive further analyses on other BER proteins and might imply that nucleic acid processing enzymes are more versatile than originally thought having evolved DNA-targeted functions after a previous life in the early RNA world.
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Affiliation(s)
- Giulia Antoniali
- Department of Medical and Biological Sciences, University of Udine , Udine, Italy
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30
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Sepúlveda S, Valenzuela L, Ponce I, Sierra S, Bahamondes P, Ramirez S, Rojas V, Kemmerling U, Galanti N, Cabrera G. Expression, Functionality, and Localization of Apurinic/Apyrimidinic Endonucleases in Replicative and Non-Replicative Forms ofTrypanosoma cruzi. J Cell Biochem 2013; 115:397-409. [DOI: 10.1002/jcb.24675] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/10/2013] [Indexed: 12/11/2022]
Affiliation(s)
- S. Sepúlveda
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - L. Valenzuela
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - I. Ponce
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - S. Sierra
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - P. Bahamondes
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - S. Ramirez
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - V. Rojas
- Laboratorio de Genética e Inmunología Molecular; Instituto de Biología, Pontificia Universidad Católica de Valparaíso; Chile
| | - U. Kemmerling
- Programa de Anatomía y Biología del Desarrollo; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - N. Galanti
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
| | - G. Cabrera
- Programa de Biología Celular y Molecular; Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile; Santiago Chile
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Illuzzi JL, Harris NA, Manvilla BA, Kim D, Li M, Drohat AC, Wilson DM. Functional assessment of population and tumor-associated APE1 protein variants. PLoS One 2013; 8:e65922. [PMID: 23776569 PMCID: PMC3679070 DOI: 10.1371/journal.pone.0065922] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/29/2013] [Indexed: 01/15/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is the predominant AP site repair enzyme in mammals. APE1 also maintains 3'-5' exonuclease and 3'-repair activities, and regulates transcription factor DNA binding through its REF-1 function. Since complete or severe APE1 deficiency leads to embryonic lethality and cell death, it has been hypothesized that APE1 protein variants with slightly impaired function will contribute to disease etiology. Our data indicate that except for the endometrial cancer-associated APE1 variant R237C, the polymorphic variants Q51H, I64V and D148E, the rare population variants G241R, P311S and A317V, and the tumor-associated variant P112L exhibit normal thermodynamic stability of protein folding; abasic endonuclease, 3'-5' exonuclease and REF-1 activities; coordination during the early steps of base excision repair; and intracellular distribution when expressed exogenously in HeLa cells. The R237C mutant displayed reduced AP-DNA complex stability, 3'-5' exonuclease activity and 3'-damage processing. Re-sequencing of the exonic regions of APE1 uncovered no novel amino acid substitutions in the 60 cancer cell lines of the NCI-60 panel, or in HeLa or T98G cancer cell lines; only the common D148E and Q51H variants were observed. Our results indicate that APE1 missense mutations are seemingly rare and that the cancer-associated R237C variant may represent a reduced-function susceptibility allele.
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Affiliation(s)
- Jennifer L. Illuzzi
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Nicole A. Harris
- Department of Cardiopathology, Sanford Burnham Medical Research Institute, Orlando, Florida, United States of America
| | - Brittney A. Manvilla
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Daemyung Kim
- Department of Genetic Engineering, Cheongju University, Cheongju, Republic of Korea
| | - Mengxia Li
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Alexander C. Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - David M. Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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Timofeyeva NA, Koval VV, Ishchenko AA, Saparbaev MK, Fedorova OS. Lys98 substitution in human AP endonuclease 1 affects the kinetic mechanism of enzyme action in base excision and nucleotide incision repair pathways. PLoS One 2011; 6:e24063. [PMID: 21912662 PMCID: PMC3164677 DOI: 10.1371/journal.pone.0024063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/04/2011] [Indexed: 11/18/2022] Open
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key enzyme in the base excision repair (BER) and nucleotide incision repair (NIR) pathways. We recently analyzed the conformational dynamics and kinetic mechanism of wild-type (wt) protein, in a stopped-flow fluorescence study. In this study, we investigated the mutant enzyme APE1K98A using the same approach. Lys98 was known to hydrogen bond to the carboxyl group of Asp70, a residue implicated in binding the divalent metal ion. Our data suggested that the conformational selection and induced fit occur during the enzyme action. We expanded upon the evidence that APE1 can pre-exist in two conformations. The isomerization of an enzyme-product complex in the BER process and the additional isomerization stage of enzyme-substrate complex in the NIR process were established for APE1K98A. These stages had not been registered for the wtAPE1. We found that the K98A substitution resulted in a 12-fold reduction of catalytic constant of 5'-phosphodiester bond hydrolysis in (3-hydroxytetrahydrofuran-2-yl)methyl phosphate (F, tetrahydrofuran) containing substrate, and in 200-fold reduction in 5,6-dihydrouridine (DHU) containing substrate. Thus, the K98A substitution influenced NIR more than BER. We demonstrated that the K98A mutation influenced the formation of primary unspecific enzyme-substrate complex in a complicated manner, depending on the Mg(2+) concentration and pH. This mutation obstructed the induced fit of enzyme in the complex with undamaged DNA and F-containing DNA and appreciably decreased the stability of primary complex upon interaction of enzyme with DNA, containing the natural apurinic/apyrimidinic (AP) site. Furthermore, it significantly delayed the activation of the less active form of enzyme during NIR and slowed down the conformational conversion of the complex of enzyme with the cleavage product of DHU-substrate. Our data revealed that APE1 uses the same active site to catalyze the cleavage of DHU- and AP-substrates.
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Affiliation(s)
- Nadezhda A. Timofeyeva
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Vladimir V. Koval
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Alexander A. Ishchenko
- CNRS UMR8200 Université Paris-Sud XI, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Murat K. Saparbaev
- CNRS UMR8200 Université Paris-Sud XI, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Olga S. Fedorova
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- * E-mail:
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Kim WC, Berquist BR, Chohan M, Uy C, Wilson DM, Lee CH. Characterization of the endoribonuclease active site of human apurinic/apyrimidinic endonuclease 1. J Mol Biol 2011; 411:960-71. [PMID: 21762700 DOI: 10.1016/j.jmb.2011.06.050] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Revised: 06/27/2011] [Accepted: 06/30/2011] [Indexed: 11/17/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is the major mammalian enzyme in DNA base excision repair that cleaves the DNA phosphodiester backbone immediately 5' to abasic sites. Recently, we identified APE1 as an endoribonuclease that cleaves a specific coding region of c-myc mRNA in vitro, regulating c-myc mRNA level and half-life in cells. Here, we further characterized the endoribonuclease activity of APE1, focusing on the active-site center of the enzyme previously defined for DNA nuclease activities. We found that most site-directed APE1 mutant proteins (N68A, D70A, Y171F, D210N, F266A, D308A, and H309S), which target amino acid residues constituting the abasic DNA endonuclease active-site pocket, showed significant decreases in endoribonuclease activity. Intriguingly, the D283N APE1 mutant protein retained endoribonuclease and abasic single-stranded RNA cleavage activities, with concurrent loss of apurinic/apyrimidinic (AP) site cleavage activities on double-stranded DNA and single-stranded DNA (ssDNA). The mutant proteins bound c-myc RNA equally well as wild-type (WT) APE1, with the exception of H309N, suggesting that most of these residues contributed primarily to RNA catalysis and not to RNA binding. Interestingly, both the endoribonuclease and the ssRNA AP site cleavage activities of WT APE1 were present in the absence of Mg(2+), while ssDNA AP site cleavage required Mg(2+) (optimally at 0.5-2.0 mM). We also found that a 2'-OH on the sugar moiety was absolutely required for RNA cleavage by WT APE1, consistent with APE1 leaving a 3'-PO(4)(2-) group following cleavage of RNA. Altogether, our data support the notion that a common active site is shared for the endoribonuclease and other nuclease activities of APE1; however, we provide evidence that the mechanisms for cleaving RNA, abasic single-stranded RNA, and abasic DNA by APE1 are not identical, an observation that has implications for unraveling the endoribonuclease function of APE1 in vivo.
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Affiliation(s)
- Wan-Cheol Kim
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, Canada V2N 4Z9
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Tell G, Fantini D, Quadrifoglio F. Understanding different functions of mammalian AP endonuclease (APE1) as a promising tool for cancer treatment. Cell Mol Life Sci 2010; 67:3589-608. [PMID: 20706766 PMCID: PMC11115856 DOI: 10.1007/s00018-010-0486-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/27/2022]
Abstract
The apurinic endonuclease 1/redox factor-1 (APE1) has a crucial function in DNA repair and in redox signaling in mammals, and recent studies identify it as an excellent target for sensitizing tumor cells to chemotherapy. APE1 is an essential enzyme in the base excision repair pathway of DNA lesions caused by oxidation and alkylation. As importantly, APE1 also functions as a redox agent maintaining transcription factors involved in cancer promotion and progression in an active reduced state. Very recently, a new unsuspected function of APE1 in RNA metabolism was discovered, opening new perspectives for this multifunctional protein. These observations underline the necessity to understand the molecular mechanisms responsible for fine-tuning its different biological functions. This survey intends to give an overview of the multifunctional roles of APE1 and their regulation in the context of considering this protein a promising tool for anticancer therapy.
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Affiliation(s)
- Gianluca Tell
- Department of Biomedical Sciences and Technologies, University of Udine, Piazzale Kolbe 4, 33100, Udine, Italy.
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35
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Borjigin M, Martinez B, Purohit S, de la Rosa G, Arenaz P, Stec B. Chinese hamster apurinic/apyrimidinic endonuclease (chAPE1) expressed in sf9 cells reveals that its endonuclease activity is regulated by phosphorylation. FEBS J 2010; 277:4732-40. [PMID: 20955519 DOI: 10.1111/j.1742-4658.2010.07879.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apurinic/apyrimidinic endonuclease (APE), an essential DNA repair enzyme, initiates the base excision repair pathway by creating a nick 5' to an abasic site in double-stranded DNA. Although the Chinese hamster ovary cells remain an important model for DNA repair studies, the Chinese hamster APE (chAPE1) has not been studied in vitro in respect to its kinetic characteristics. Here we report the results of a kinetic study performed on cloned and overexpressed enzyme in sf9 cells. The kinetic parameters were fully compatible with the broad range of kinetic parameters reported for the human enzyme. However, the activity measures depended on the time point of the culture. We applied inductivity coupled plasma spectrometry to measure the phosphorylation level of chAPE1. Our data showed that a higher phosphorylation of chAPE1 in the expression host was correlated to a lower endonuclease activity. The phosphorylation of a higher activity batch of chAPE1 by casein kinase II decreased the endonuclease activity, and the dephosphorylation of chAPE1 by lambda phosphatase increased the endonuclease activity. The exonuclease activity of chAPE1 was not observed in our kinetic analysis. The results suggest that noticeable divergence in reported activity levels for the human APE1 endonuclease might be caused by unaccounted phosphorylation. Our data also demonstrate that only selected kinases and phosphatases exert regulatory effects on chAPE1 endonuclease activity, suggesting further that this regulatory mechanism may function in vivo to turn on and off the function of this important enzyme in different organisms.
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Affiliation(s)
- Mandula Borjigin
- Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA.
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Tomecki R, Dziembowski A. Novel endoribonucleases as central players in various pathways of eukaryotic RNA metabolism. RNA (NEW YORK, N.Y.) 2010; 16:1692-1724. [PMID: 20675404 PMCID: PMC2924532 DOI: 10.1261/rna.2237610] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
For a long time it has been assumed that the decay of RNA in eukaryotes is mainly carried out by exoribonucleases, which is in contrast to bacteria, where endoribonucleases are well documented to initiate RNA degradation. In recent years, several as yet unknown endonucleases have been described, which has changed our view on eukaryotic RNA metabolism. Most importantly, it was shown that the primary eukaryotic 3' --> 5' exonuclease, the exosome complex has the ability to endonucleolytically cleave its physiological RNA substrates, and novel endonucleases involved in both nuclear and cytoplasmic RNA surveillance pathways were discovered concurrently. In addition, endoribonucleases responsible for long-known processing steps in the maturation pathways of various RNA classes were recently identified. Moreover, one of the most intensely studied RNA decay pathways--RNAi--is controlled and stimulated by the action of different endonucleases. Furthermore, endoribonucleolytic cleavages executed by various enzymes are also the hallmark of RNA degradation and processing in plant chloroplasts. Finally, multiple context-specific endoribonucleases control qualitative and/or quantitative changes of selected transcripts under particular conditions in different eukaryotic organisms. The aim of this review is to discuss the impact of all of these discoveries on our current understanding of eukaryotic RNA metabolism.
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Affiliation(s)
- Rafal Tomecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, University of Warsaw, 02-106 Warsaw, Poland
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Gelin A, Redrejo-Rodríguez M, Laval J, Fedorova OS, Saparbaev M, Ishchenko AA. Genetic and biochemical characterization of human AP endonuclease 1 mutants deficient in nucleotide incision repair activity. PLoS One 2010; 5:e12241. [PMID: 20808930 PMCID: PMC2923195 DOI: 10.1371/journal.pone.0012241] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 07/25/2010] [Indexed: 11/19/2022] Open
Abstract
Background Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key DNA repair enzyme involved in both base excision repair (BER) and nucleotide incision repair (NIR) pathways. In the BER pathway, APE1 cleaves DNA at AP sites and 3′-blocking moieties generated by DNA glycosylases. In the NIR pathway, APE1 incises DNA 5′ to a number of oxidatively damaged bases. At present, physiological relevance of the NIR pathway is fairly well established in E. coli, but has yet to be elucidated in human cells. Methodology/Principal Finding We identified amino acid residues in the APE1 protein that affect its function in either the BER or NIR pathway. Biochemical characterization of APE1 carrying single K98A, R185A, D308A and double K98A/R185A amino acid substitutions revealed that all mutants exhibited greatly reduced NIR and 3′→5′ exonuclease activities, but were capable of performing BER functions to some extent. Expression of the APE1 mutants deficient in the NIR and exonuclease activities reduced the sensitivity of AP endonuclease-deficient E. coli xth nfo strain to an alkylating agent, methylmethanesulfonate, suggesting that our APE1 mutants are able to repair AP sites. Finally, the human NIR pathway was fully reconstituted in vitro using the purified APE1, human flap endonuclease 1, DNA polymerase β and DNA ligase I proteins, thus establishing the minimal set of proteins required for a functional NIR pathway in human cells. Conclusion/Significance Taken together, these data further substantiate the role of NIR as a distinct and separable function of APE1 that is essential for processing of potentially lethal oxidative DNA lesions.
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Affiliation(s)
- Aurore Gelin
- CNRS UMR8126, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Modesto Redrejo-Rodríguez
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Jacques Laval
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Olga S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Murat Saparbaev
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Alexander A. Ishchenko
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
- * E-mail:
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Lakomek K, Dickmanns A, Ciirdaeva E, Schomacher L, Ficner R. Crystal structure analysis of DNA uridine endonuclease Mth212 bound to DNA. J Mol Biol 2010; 399:604-17. [PMID: 20434457 DOI: 10.1016/j.jmb.2010.04.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 04/21/2010] [Indexed: 11/30/2022]
Abstract
The reliable repair of pre-mutagenic U/G mismatches that originated from hydrolytic cytosine deamination is crucial for the maintenance of the correct genomic information. In most organisms, any uracil base in DNA is attacked by uracil DNA glycosylases (UDGs), but at least in Methanothermobacter thermautotrophicus DeltaH, an alternative strategy has evolved. The exonuclease III homologue Mth212 from the thermophilic archaeon M. thermautotrophicus DeltaH exhibits a DNA uridine endonuclease activity in addition to the apyrimidinic/apurinic site endonuclease and 3'-->5'exonuclease functions. Mth212 alone compensates for the lack of a UDG in a single-step reaction thus substituting the two-step pathway that requires the consecutive action of UDG and apyrimidinic/apurinic site endonuclease. In order to gain deeper insight into the structural basis required for the specific uridine recognition by Mth212, we have characterized the enzyme by means of X-ray crystallography. Structures of Mth212 wild-type or mutant proteins either alone or in complex with DNA substrates and products have been determined to a resolution of up to 1.2 A, suggesting key residues for the uridine endonuclease activity. The insertion of the side chain of Arg209 into the DNA helical base stack resembles interactions observed in human UDG and seems to be crucial for the uridine recognition. In addition, Ser171, Asn153, and Lys125 in the substrate binding pocket appear to have important functions in the discrimination of aberrant uridine against naturally occurring thymidine and cytosine residues in double-stranded DNA.
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Affiliation(s)
- Kristina Lakomek
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Justus-von-Liebig Weg 11, D-37077 Göttingen, Germany
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Kim WC, King D, Lee CH. RNA-cleaving properties of human apurinic/apyrimidinic endonuclease 1 (APE1). INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2010; 1:12-25. [PMID: 21968700 PMCID: PMC3180037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 03/03/2010] [Indexed: 05/31/2023]
Abstract
We have recently identified apurinic/apyrimidinic endonuclease 1 (APE1) as an endoribonuclease that cleaves c-myc mRNA in vitro and regulates c-myc mRNA levels and half-life in cells. This study was undertaken to further unravel the RNA-cleaving properties of APE1. Here, we show that APE1 cleaves RNA in the absence of divalent metal ions and, at 2 mM, Zn(2+), Ni(2+), Cu(2+), or Co(2+) inhibited the endoribonuclease activity of APE1. APE1 is able to cleave CD44 mRNA, microRNAs (miR-21, miR-10b), and three RNA components of SARS-corona virus (orf1b, orf3, spike) suggesting that, when challenged, it can cleave any RNAs in vitro. APE1 does not cleave strong doublestranded regions of RNA and it has a strong preference for 3' of pyrimidine, especially towards UA, CA, and UG sites at single-stranded or weakly paired regions. It also cleaves RNA weakly at UC, CU, AC, and AU sites in single-stranded or weakly paired regions. Finally, we found that APE1 can reduce the ability of the Dicer enzyme to process premiRNAs in vitro. Overall, this study has revealed some previously unknown biochemical properties of APE1 which has implications for its role in vivo.
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Affiliation(s)
- Wan-Cheol Kim
- Chemistry Program, University of Northern British Columbia, 3333 University Way Prince George, BC V2N 4Z9 Canada
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40
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Endoribonuclease activity of human apurinic/apyrimidinic endonuclease 1 revealed by a real-time fluorometric assay. Anal Biochem 2009; 398:69-75. [PMID: 19932678 DOI: 10.1016/j.ab.2009.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 10/22/2009] [Accepted: 11/16/2009] [Indexed: 11/21/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme with a well-established abasic DNA cleaving activity in the base excision DNA repair pathway and in providing redox activity to several well-known transcription factors. APE1 has recently been shown to cleave at the UA, CA, and UG sites of c-myc RNA in vitro and regulates c-myc messenger RNA (mRNA) in cells. To further understand this new endoribonuclease activity of APE1, we have developed an accurate, sensitive, and rapid real-time endonuclease assay based on a fluorogenic oligodeoxynucleotide substrate with a single ribonucleotide. Using this substrate, we carried out the first kinetic analysis of APE1 endoribonuclease activity. We found that the purified native APE1 cleaves the fluorogenic substrate efficiently, as revealed by a k(cat)/K(m) of 2.62x10(6)M(-1)s(-1), a value that is only 71-fold lower than that obtained with the potent bovine pancreatic RNase A. Ion concentrations ranging from 0.2 to 2mM Mg2+ promoted catalysis, whereas 10 to 20mM Mg2+ was inhibitory to the RNA-cleaving activity of APE1. The monovalent cation K+ was inhibitory except at 20mM, where it significantly stimulated recombinant APE1 activity. These results demonstrate rapid and specific endoribonucleolytic cleavage by APE1 and support the notion that this activity is a previously undefined function of APE1.
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Ahn J, Poyurovsky MV, Baptiste N, Beckerman R, Cain C, Mattia M, McKinney K, Zhou J, Zupnick A, Gottifredi V, Prives C. Dissection of the sequence-specific DNA binding and exonuclease activities reveals a superactive yet apoptotically impaired mutant p53 protein. Cell Cycle 2009; 8:1603-15. [PMID: 19462533 DOI: 10.4161/cc.8.10.8548] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Both sequence-specific DNA binding and exonuclease activities have been mapped to the central conserved core domain of p53. To gain more information about these two activities a series of mutants were generated that changed core domain histidine residues. Of these mutants, only one, H115N p53, showed markedly reduced exonuclease activity (ca. 15% of wild-type). Surprisingly, purified H115N p53 protein was found to be significantly more potent than wild-type p53 in binding to DNA by several criteria including gel mobility shift assay, filter binding and DNase I footprinting. Interestingly as well, non-specific DNA binding by the core domain of H115N p53 is superior to that of wild-type p53. To study H115N p53 in vivo, clones of H1299 cells expressing tetracycline regulated wild-type or H115N p53 were generated. H115N was both more potent than wild-type p53 in inducing p53 target genes such as p21 and PIG3 and was also more effective in arresting cells in G1. Unexpectedly, in contrast to wild-type p53, H115N p53 was markedly impaired in causing apoptosis when cells were subjected to DNA damage. Our results indicate that the exonuclease activity and transcriptional activation functions of p53 can be separated. They also extend previous findings showing that cell cycle arrest and apoptosis are separable functions of p53. Finally, these experiments confirm that DNA binding and xonuclease activities are distinct features of the p53 core domain.
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Affiliation(s)
- Jinwoo Ahn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Belloni P, Meschini R, Czene S, Harms-Ringdahl M, Palitti F. Studies on radiation-induced apoptosis in G0human lymphocytes. Int J Radiat Biol 2009; 81:587-99. [PMID: 16298940 DOI: 10.1080/09553000500303690] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE To determine the relationships between the frequencies of radiation-induced chromosomal alterations and the extent of apoptosis in G0 human lymphocytes. MATERIAL AND METHODS G0 human peripheral blood lymphocytes (HPBL) were X or gamma-irradiated, in the presence or absence of the repair inhibitor cytosine arabinoside (Ara-C). Directly after irradiation, a part of the lymphocytes were stimulated to grow while the rest were stimulated 48 h after irradiation. These lymphocyte cultures were analysed for induction of chromosomal aberrations. A subset of lymphocytes was kept in G0 and analysed for cell viability, apoptosis and p53 expression. RESULTS The fraction of cells bearing dicentrics was reduced in lymphocytes stimulated to grow 48 h post irradiation as compared to lymphocytes stimulated immediately after irradiation. The decrease in the frequency of dicentrics correlated with the increase in the number of apoptotic cells. The operative apoptotic pathway in irradiated Go lymphocytes was dependent on the expression of p53. CONCLUSIONS The radiation-induced apoptotic response of G0 lymphocytes is p53 dependent and increases with the time they are held in G0. When mitogen was added 48 h after irradiation, cells with dicentrics were either preferentially eliminated or did not enter mitosis. Thus the radiation-induced damage can be underevaluated depending on the time between radiation exposure and the induction of proliferation. These results may have relevance for biodosimetry studies or for evaluations of the efficacy of radiotherapy which are based on the frequencies of chromosomal aberrations.
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Affiliation(s)
- P Belloni
- Dipartimento di Agrobiologia e Agrochimica, Università degli Studi della Tuscia, Viterbo, Italy
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Barnes T, Kim WC, Mantha AK, Kim SE, Izumi T, Mitra S, Lee CH. Identification of Apurinic/apyrimidinic endonuclease 1 (APE1) as the endoribonuclease that cleaves c-myc mRNA. Nucleic Acids Res 2009; 37:3946-58. [PMID: 19401441 PMCID: PMC2709568 DOI: 10.1093/nar/gkp275] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 04/01/2009] [Accepted: 04/13/2009] [Indexed: 11/28/2022] Open
Abstract
Endonucleolytic cleavage of the coding region determinant (CRD) of c-myc mRNA appears to play a critical role in regulating c-myc mRNA turnover. Using (32)P-labeled c-myc CRD RNA as substrate, we have purified and identified two endoribonucleases from rat liver polysomes that are capable of cleaving the transcript in vitro. A 17-kDa enzyme was identified as RNase1. Apurinic/apyrimidinic (AP) DNA endonuclease 1 (APE1) was identified as the 35-kDa endoribonuclease that preferentially cleaves in between UA and CA dinucleotides of c-myc CRD RNA. APE1 was further confirmed to be the 35-kDa endoribonuclease because: (i) the endoribonuclease activity of the purified 35-kDa native enzyme was specifically immuno-depleted with APE1 monoclonal antibody, and (ii) recombinant human APE1 generated identical RNA cleavage patterns as the native liver enzyme. Studies using E96A and H309N mutants of APE1 suggest that the endoribonuclease activity for c-myc CRD RNA shares the same active center with the AP-DNA endonuclease activity. Transient knockdown of APE1 in HeLa cells led to increased steady-state level of c-myc mRNA and its half-life. We conclude that the ability to cleave RNA dinucleotides is a previously unidentified function of APE1 and it can regulate c-myc mRNA level possibly via its endoribonuclease activity.
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Affiliation(s)
- Tavish Barnes
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Wan-Cheol Kim
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Anil K. Mantha
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Sang-Eun Kim
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Tadahide Izumi
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Sankar Mitra
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
| | - Chow H. Lee
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada, Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 and Health Sciences Center, Louisiana State University, New Orleans, LA 70112, USA
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44
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Timofeyeva NA, Koval VV, Knorre DG, Zharkov DO, Saparbaev MK, Ishchenko AA, Fedorova OS. Conformational dynamics of human AP endonuclease in base excision and nucleotide incision repair pathways. J Biomol Struct Dyn 2009; 26:637-52. [PMID: 19236113 DOI: 10.1080/07391102.2009.10507278] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
APE1 is a multifunctional enzyme that plays a central role in base excision repair (BER) of DNA. APE1 is also involved in the alternative nucleotide incision repair (NIR) pathway. We present an analysis of conformational dynamics and kinetic mechanisms of the full-length APE1 and truncated NDelta61-APE1 lacking the N-terminal 61 amino acids (REF1 domain) in BER and NIR pathways. The action of both enzyme forms were described by identical kinetic schemes, containing four stages corresponding to formation of the initial enzyme-substrate complex and isomerization of this complex; when a damaged substrate was present, these stages were followed by an irreversible catalytic stage resulting in the formation of the enzyme-product complex and the equilibrium stage of product release. For the first time we showed, that upon binding AP-containing DNA, the APE1 structure underwent conformational changes before the chemical cleavage step. Under BER conditions, the REF1 domain of APE1 influenced the stability of both the enzyme-substrate and enzyme-product complexes, as well as the isomerization rate, but did not affect the rates of initial complex formation or catalysis. Under NIR conditions, the REF1 domain affected both the rate of formation and the stability of the initial complex. In comparison with the full-length protein, NDelta61-APE1 did not display a decrease in NIR activity with a dihydrouracil-containing substrate. BER conditions decrease the rate of catalysis and strongly inhibit the rate of isomerization step for the NIR substrates. Under NIR conditions AP-endonuclease activity is still very efficient.
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Affiliation(s)
- N A Timofeyeva
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk State University, Russia.
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Abstract
The DNA base excision repair (BER) pathway repairs alkylation and oxidative DNA damage caused by endogenous and exogenous agents, including chemotherapeutic agents. Upon removal of the damaged base AP endonuclease 1 (Ape1), a critical component of the pathway cleaves the abasic site to facilitate repair. Ape1 is a multifunctional protein which plays a role not only in DNA repair but it also functions as a reduction-oxidation factor, known as Ref-1 in the literature, to increase the DNA binding ability of several transcription factors involved in different growth signaling pathways. Elevated levels of Ape1 have been linked to resistance to chemotherapy, poor prognosis, and poor survival. Reducing the amount of Ape1 protein in cancer cells and tumors using RNA interference and anti-sense oligonucleotide technology sensitizes mammalian tumor cells to a variety of laboratory and chemotherapeutic agents. Therefore, selective inhibition of Ape1's DNA repair activity is a promising avenue to develop novel cancer therapeutics.
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Affiliation(s)
- Aditi Bapat
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Yang S, Meyskens FL. Apurinic/apyrimidinic endonuclease/redox effector factor-1(APE/Ref-1): a unique target for the prevention and treatment of human melanoma. Antioxid Redox Signal 2009; 11:639-50. [PMID: 18715151 PMCID: PMC2933576 DOI: 10.1089/ars.2008.2226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Management of melanoma is a growing and challenging public health issue requiring novel and multidisciplinary approaches to achieve more efficient prevention and therapeutic benefits. The aim of this article is to show the critical role of APE/Ref-1 on melanomagenesis and progression. APE/Ref-1 serves as a redox-sensitive node of convergence of various signals as well as a DNA-repair enzyme, and its activation protects melanocytes and melanoma cells from chronic oxidative stress and promotes cell survival via mediation of downstream pathways. APE/Ref-1 is a strong candidate as a potential drug-treatable target for the prevention and treatment of human melanoma. Lead compounds exhibiting inhibitory effects on APE/Ref-1 are also reviewed. We anticipate potential clinical benefit in the future through inhibition of APE/Ref-1 and/or Ref-1-mediated signaling.
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Affiliation(s)
- Sun Yang
- Chao Family Comprehensive Cancer Center, Department of Medicine, Orange, California, USA
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Berquist BR, McNeill DR, Wilson DM. Characterization of abasic endonuclease activity of human Ape1 on alternative substrates, as well as effects of ATP and sequence context on AP site incision. J Mol Biol 2008; 379:17-27. [PMID: 18439621 DOI: 10.1016/j.jmb.2008.03.053] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/07/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
Abstract
Human Ape1 is a multifunctional protein with a major role in initiating repair of apurinic/apyrimidinic (AP) sites in DNA by catalyzing hydrolytic incision of the phosphodiester backbone immediately adjacent to the damage. Besides in double-stranded DNA, Ape1 has been shown to cleave at AP sites in single-stranded regions of a number of biologically relevant DNA conformations and in structured single-stranded DNA. Extension of these studies has revealed a more expansive repertoire of model substrates on which Ape1 exerts AP endonuclease activity. In particular, Ape1 possesses the ability to cleave at AP sites located in (i) the DNA strand of a DNA/RNA hybrid, (ii) "pseudo-triplex" bubble substrates designed to mimic stalled replication or transcription intermediates, and (iii) configurations that emulate R-loop structures that arise during class switch recombination. Moreover, Ape1 was found to cleave AP-site-containing single-stranded RNA, suggesting a novel "cleansing" function that may contribute to the elimination of detrimental cellular AP-RNA molecules. Finally, sequence context immediately surrounding an abasic site in duplex DNA was found to have a less than threefold effect on the incision efficiency of Ape1, and ATP was found to exert complex effects on the endonuclease capacity of Ape1 on double-stranded substrates. The results suggest that in addition to abasic sites in conventional duplex genomic DNA, Ape1 has the ability to incise at AP sites in DNA conformations formed during DNA replication, transcription, and class switch recombination, and that Ape1 can endonucleolytically destroy damaged RNA.
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Affiliation(s)
- Brian R Berquist
- Unit of Structure and Function in Base Excision Repair, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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Vidal AE, Harkiolaki M, Gallego C, Castillo-Acosta VM, Ruiz-Pérez LM, Wilson K, González-Pacanowska D. Crystal Structure and DNA Repair Activities of the AP Endonuclease from Leishmania major. J Mol Biol 2007; 373:827-38. [PMID: 17870086 DOI: 10.1016/j.jmb.2007.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/24/2007] [Accepted: 08/01/2007] [Indexed: 12/31/2022]
Abstract
Apurinic/apyrimidinic endonucleases initiate the repair of abasic sites produced either spontaneously, from attack of bases by reactive oxygen species or as intermediates during base excision repair. The catalytic properties and crystal structure of Leishmania major apurinic/apyrimidinic endonuclease are described and compared with those of human APE1 and bacterial exonuclease III. The purified enzyme is shown to possess apurinic/apyrimidinic endonuclease activity of the same order as eukaryotic and prokaryotic counterparts and an equally robust 3'-phosphodiesterase activity. Consistent with this, expression of the L. major endonuclease confers resistance to both methyl methane sulphonate and H2O2 in Escherichia coli repair-deficient mutants while expression of the human homologue only reverts methyl methane sulphonate sensitivity. Structural analyses and modelling of the enzyme-DNA complex demonstrates a high degree of conservation to previously characterized homologues, although subtle differences in the active site geometry might account for the high 3'-phosphodiesterase activity. Our results confirm that the L. major's enzyme is a key element in mediating repair of apurinic/apyrimidinic sites and 3'-blocked termini and therefore must play an important role in the survival of kinetoplastid parasites after exposure to the highly oxidative environment within the host macrophage.
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Affiliation(s)
- Antonio E Vidal
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla, Granada, Spain
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Rogers K, Gao G, Simpson L. Uridylate-specific 3' 5'-exoribonucleases involved in uridylate-deletion RNA editing in trypanosomatid mitochondria. J Biol Chem 2007; 282:29073-80. [PMID: 17699520 DOI: 10.1074/jbc.m704551200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In kinetoplastid protists, maturation of mitochondrial pre-mRNAs involves the insertion and deletion of uridylates (Us) within coding regions, as specified by mitochondrial DNA-encoded guide RNAs. U-deletion editing involves endonucleolytic cleavage of the pre-mRNA at the editing site followed by U-specific 3'-5'-exonucleolytic removal of nonbase-paired Us prior to ligation of the two mRNA cleavage fragments. We showed previously that an exonuclease/endonuclease/phosphatase (EEP) motif protein from Leishmania major, designated RNA editing exonuclease 1 (REX1) (Kang, X., Rogers, K., Gao, G., Falick, A. M., Zhou, S.-L., and Simpson, L. (2005) Proc. Natl. Acad. Sci. U. S. A. 102, 1017-1022), exhibits 3'-5'-exonuclease activity. Two EEP motif proteins have also been identified in the Trypanosoma brucei editing complex. TbREX1 is a homologue of LmREX1, and TbREX2 shows homology to another editing protein in L. major, which lacks the EEP motif (LmREX2*). Here we have expressed the T. brucei EEP motif proteins in insect cells and purified them to homogeneity. We showed that these are U-specific 3'-5'-exonucleases that are inhibited by base pairing of 3' Us. The recombinant EEP motif alone also showed 3'-5' U-specific exonuclease activity, and mutations of the REX EEP motifs greatly reduced exonuclease activity. The absence of enzymatic activity in LmREX2* was confirmed with a purified recombinant protein. We showed that pre-cleaved U-deletion editing could be reconstituted with either TbREX1 or TbREX2 in combination with either RNA ligase, LmREL1, or LmREL2. Down-regulation of TbREX2 expression by conditional RNA interference had little effect on parasite viability or sedimentation of the L-complex, suggesting either that TbREX2 is inactive in vivo or that TbREX1 can compensate for the loss of TbREX2 function in down-regulated cells.
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Affiliation(s)
- Kestrel Rogers
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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