title: The role of the mammalian DNA end-processing enzyme polynucleotide kinase 3'-phosphatase in spinocerebellar ataxia type 3 pathogenesis.
abstract: DNA strand-breaks (SBs) with non-ligatable ends are generated by ionizing radiation, oxidative stress, various chemotherapeutic agents, and also as base excision repair (BER) intermediates. Several neurological diseases have already been identified as being due to a deficiency in DNA end-processing activities. Two common dirty ends, 3'-P and 5'-OH, are processed by mammalian polynucleotide kinase 3'-phosphatase (PNKP), a bifunctional enzyme with 3'-phosphatase and 5'-kinase activities. We have made the unexpected observation that PNKP stably associates with Ataxin-3 (ATXN3), a polyglutamine repeat-containing protein mutated in spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph Disease (MJD). This disease is one of the most common dominantly inherited ataxias worldwide; the defect in SCA3 is due to CAG repeat expansion (from the normal 14-41 to 55-82 repeats) in the ATXN3 coding region. However, how the expanded form gains its toxic function is still not clearly understood. Here we report that purified wild-type (WT) ATXN3 stimulates, and by contrast the mutant form specifically inhibits, PNKP's 3' phosphatase activity in vitro. ATXN3-deficient cells also show decreased PNKP activity. Furthermore, transgenic mice conditionally expressing the pathological form of human ATXN3 also showed decreased 3'-phosphatase activity of PNKP, mostly in the deep cerebellar nuclei, one of the most affected regions in MJD patients' brain. Finally, long amplicon quantitative PCR analysis of human MJD patients' brain samples showed a significant accumulation of DNA strand breaks. Our results thus indicate that the accumulation of DNA strand breaks due to functional deficiency of PNKP is etiologically linked to the pathogenesis of SCA3/MJD.
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Arpita
authors: A
authors: Chatterjee
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Saikat
authors: S
authors: Saha
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Anirban
authors: A
authors: Chakraborty
authors: School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors: Anabela
authors: A
authors: Silva-Fernandes
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Santi M
authors: SM
authors: Mandal
authors: School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors: Andreia
authors: A
authors: Neves-Carvalho
authors: Department of Neurology and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Yongping
authors: Y
authors: Liu
authors: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America; Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas, United States of America.
authors: Raj K
authors: RK
authors: Pandita
authors: Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas, United States of America; Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Muralidhar L
authors: ML
authors: Hegde
authors: Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas, United States of America; Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Pavana M
authors: PM
authors: Hegde
authors: Department of Microbiology & Immunology; University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Istvan
authors: I
authors: Boldogh
authors: Department of Neurology, University of Florida, Gainesville, Florida, United States of America.
authors: Tetsuo
authors: T
authors: Ashizawa
authors: Department of Neurology, Albany Stratton VA Medical Center, Albany, New York, United States of America.
authors: Arnulf H
authors: AH
authors: Koeppen
authors: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America; Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas, United States of America.
authors: Tej K
authors: TK
authors: Pandita
authors: School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors: Patricia
authors: P
authors: Maciel
authors: Department of Neurology and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Partha S
authors: PS
authors: Sarkar
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Tapas K
authors: TK
authors: Hazra
mesh_terms: D000818:Animals; D000067699:Ataxin-3; D002460:Cell Line; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D045643:DNA Repair Enzymes / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017827:Machado-Joseph Disease / Q000201:enzymology / Q000235:genetics* / Q000503:physiopathology; D008322:Mammals; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
chemical_list: D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C530380:PNKP protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor); C092341:ATXN3 protein, human; D000067699:Ataxin-3; D045643:DNA Repair Enzymes
references: DNA Repair (Amst). 2003 Oct 7;2(10):1087-100
references: 13679147
references: Cell. 2001 Jan 12;104(1):107-17
references: 11163244
references: J Biol Chem. 2004 Jan 30;279(5):3605-11
references: 14602712
references: Lancet Neurol. 2004 May;3(5):291-304
references: 15099544
references: Genomics. 2004 Aug;84(2):361-73
references: 15233999
references: Mol Cell. 2004 Jul 23;15(2):209-20
references: 15260972
references: Nucleic Acids Res. 1983 Mar 11;11(5):1475-89
references: 6828386
references: Nat Genet. 1994 Nov;8(3):221-8
references: 7874163
references: Bioessays. 2001 May;23(5):447-55
references: 11340626
references: Nat Genet. 2001 Oct;29(2):184-8
references: 11586299
references: Nat Genet. 2001 Oct;29(2):189-93
references: 11586300
references: Nat Biotechnol. 2002 May;20(5):473-7
references: 11981560
references: Nat Genet. 2002 Oct;32(2):267-72
references: 12244316
references: J Biol Chem. 2002 Nov 22;277(47):45004-12
references: 12297501
references: Mol Cell Biol. 2003 Sep;23(18):6469-83
references: 12944474
references: Oncogene. 1996 Aug 15;13(4):823-31
references: 8761304
references: Ann Neurol. 1997 Apr;41(4):453-62
references: 9124802
references: Cell. 1998 Oct 2;95(1):41-53
references: 9778246
references: Hum Mol Genet. 2003 Dec 1;12(23):3195-205
references: 14559776
references: Cell. 1998 Oct 2;95(1):55-66
references: 9778247
references: Neurobiol Dis. 2010 Oct;40(1):163-76
references: 20510362
references: J Biol Chem. 2011 Feb 25;286(8):6006-16
references: 21169365
references: EMBO Rep. 2011 Jul;12(7):713-9
references: 21637298
references: Handb Clin Neurol. 2012;103:437-49
references: 21827905
references: Nucleic Acids Res. 2011 Nov;39(21):9224-37
references: 21824916
references: Neurobiol Dis. 1998 Nov;5(5):335-47
references: 10069576
references: Brain Pathol. 1998 Oct;8(4):669-79
references: 9804376
references: J Biol Chem. 2012 Jan 20;287(4):2819-29
references: 22130663
references: Science. 1999 Jun 11;284(5421):1790-5
references: 10364545
references: Hum Mol Genet. 1999 Jul;8(7):1169-76
references: 10369861
references: J Biol Chem. 1999 Aug 20;274(34):24176-86
references: 10446192
references: J Biol Chem. 1999 Aug 20;274(34):24187-94
references: 10446193
references: Proc Natl Acad Sci U S A. 2005 Mar 22;102(12):4330-5
references: 15767577
references: Mol Cell. 2005 Apr 1;18(1):37-48
references: 15808507
references: Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12700-5
references: 16118278
references: Nat Rev Genet. 2005 Oct;6(10):729-42
references: 16205713
references: Methods Mol Biol. 2006;314:183-99
references: 16673882
references: DNA Repair (Amst). 2006 Dec 9;5(12):1439-48
references: 16982218
references: Nat Methods. 2006 Dec;3(12):995-1000
references: 17072308
references: Nature. 2007 May 24;447(7143):447-52
references: 17450122
references: J Biol Chem. 2007 Sep 7;282(36):26591-602
references: 17611195
references: Biochem Biophys Res Commun. 2007 Oct 26;362(3):734-9
references: 17764659
references: EMBO J. 2007 Nov 14;26(22):4720-31
references: 17914460
references: Proc Natl Acad Sci U S A. 2008 Jun 24;105(25):8580-4
references: 18562274
references: Nat Rev Genet. 2008 Aug;9(8):619-31
references: 18626472
references: J Biol Chem. 2008 Sep 26;283(39):26436-43
references: 18599482
references: Nat Rev Mol Cell Biol. 2010 Mar;11(3):165-70
references: 20177394
references: Nat Genet. 2010 Mar;42(3):245-9
references: 20118933
references: DNA Repair (Amst). 2012 Jun 1;11(6):570-8
references: 22497777
references: Hum Mol Genet. 2012 Nov 1;21(21):4655-68
references: 22843500
references: Nucleic Acids Res. 2012 Dec;40(22):11404-15
references: 23042680
references: Neurogenetics. 2013 Feb;14(1):43-51
references: 23224214
references: Nat Neurosci. 2013 May;16(5):613-21
references: 23525040
references: Neuroscience. 2013 Jul 23;243:14-21
references: 23562578
references: Proc Natl Acad Sci U S A. 2013 Aug 13;110(33):E3090-9
references: 23898192
references: Nat Neurosci. 2013 Nov;16(11):1523-9
references: 24165679
references: Hum Mol Genet. 2014 Mar 15;23(6):1606-18
references: 24191263
references: Neurotherapeutics. 2014 Apr;11(2):433-49
references: 24477711
references: Cell. 2014 May 8;157(4):869-81
references: 24813610
references: Hum Mol Genet. 2014 Oct 1;23(19):5188-96
references: 24833720
references: Hum Mol Genet. 2000 Jul 22;9(12):1795-803
references: 10915768
references: Methods. 2000 Oct;22(2):135-47
references: 11020328