title: Stress-induced alternative splice forms of MDM2 and MDMX modulate the p53-pathway in distinct ways.
abstract: MDM2 and MDMX are the chief negative regulators of the tumor-suppressor protein p53 and are essential for maintaining homeostasis within the cell. In response to genotoxic stress and also in several cancer types, MDM2 and MDMX are alternatively spliced. The splice variants MDM2-ALT1 and MDMX-ALT2 lack the p53-binding domain and are incapable of negatively regulating p53. However, they retain the RING domain that facilitates dimerization of the full-length MDM proteins. Concordantly, MDM2-ALT1 has been shown to lead to the stabilization of p53 through its interaction with and inactivation of full-length MDM2. The impact of MDM2-ALT1 expression on the p53 pathway and the nature of its interaction with MDMX remain unclear. Also, the role of the architecturally similar MDMX-ALT2 and its influence of the MDM2-MDMX-p53 axis are yet to be elucidated. We show here that MDM2-ALT1 is capable of binding full-length MDMX as well as full-length MDM2. Additionally, we demonstrate that MDMX-ALT2 is able to dimerize with both full-length MDMX and MDM2 and that the expression of MDM2-ALT1 and MDMX-ALT2 leads to the upregulation of p53 protein, and also of its downstream target p21. Moreover, MDM2-ALT1 expression causes cell cycle arrest in the G1 phase in a p53 and p21 dependent manner, which is consistent with the increased levels of p21. Finally we present evidence that MDM2-ALT1 and MDMX-ALT2 expression can activate subtly distinct subsets of p53-transcriptional targets implying that these splice variants can modulate the p53 tumor suppressor pathway in unique ways. In summary, our study shows that the stress-inducible alternative splice forms MDM2-ALT1 and MDMX-ALT2 are important modifiers of the p53 pathway and present a potential mechanism to tailor the p53-mediated cellular stress response.
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; The Department of Pediatrics, and Molecular, Cellular and Developmental Biology (MCDB) program, The Ohio State University, Columbus, Ohio, United States of America; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Aishwarya G
authors.initials: AG
authors.lastname: Jacob
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; The Department of Pediatrics, and Molecular, Cellular and Developmental Biology (MCDB) program, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Singh
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; The Department of Pediatrics, and Molecular, Cellular and Developmental Biology (MCDB) program, The Ohio State University, Columbus, Ohio, United States of America; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Comiskey
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Rouhier
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Fuad
authors.initials: F
authors.lastname: Mohammad
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; The Department of Pediatrics, and Molecular, Cellular and Developmental Biology (MCDB) program, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Bebee
authors.affiliation: From the Center for Childhood Cancer at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America; The Department of Pediatrics, and Molecular, Cellular and Developmental Biology (MCDB) program, The Ohio State University, Columbus, Ohio, United States of America; Center for RNA Biology, Wexner Medical Center, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Dawn S
authors.initials: DS
authors.lastname: Chandler
mesh_terms: D017398:Alternative Splicing; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D004249:DNA Damage; D006801:Humans; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism; D060066:Protein Interaction Maps; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D051736:Proto-Oncogene Proteins c-mdm2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D020033:Protein Isoforms; D016159:Tumor Suppressor Protein p53; D051736:Proto-Oncogene Proteins c-mdm2
references.citation: Crit Rev Oncol Hematol. 2000 Jan;33(1):1-6
references.pmid: 10714958
references.citation: Nat Med. 1996 Aug;2(8):912-7
references.pmid: 8705862
references.citation: J Biol Chem. 2000 Mar 24;275(12):8945-51
references.pmid: 10722742
references.citation: Cancer Res. 2004 Jun 15;64(12):4122-30
references.pmid: 15205322
references.citation: J Biol Chem. 1999 Mar 19;274(12):8299-308
references.pmid: 10075736
references.citation: Oncogene. 2002 Dec 12;21(57):8776-85
references.pmid: 12483531
references.citation: Cancer Res. 2010 Sep 15;70(18):7148-54
references.pmid: 20736370
references.citation: Mol Cell Biol. 2003 Aug;23(15):5113-21
references.pmid: 12860999
references.citation: Mol Cell Biol. 2008 Feb;28(4):1218-29
references.pmid: 18086887
references.citation: Proc Natl Acad Sci U S A. 2006 Feb 28;103(9):3232-7
references.pmid: 16492744
references.citation: Nat Struct Mol Biol. 2009 Jan;16(1):23-9
references.pmid: 19079265
references.citation: J Biol Chem. 2004 Apr 16;279(16):16000-6
references.pmid: 14761977
references.citation: Cancer Res. 2003 Sep 15;63(18):5703-6
references.pmid: 14522887
references.citation: Mol Cell Biol. 2008 Aug;28(15):4862-74
references.pmid: 18541670
references.citation: Nat Protoc. 2009;4(1):44-57
references.pmid: 19131956
references.citation: EMBO J. 2011 Jun 1;30(11):2219-32
references.pmid: 21522133
references.citation: Cell. 1992 Nov 13;71(4):587-97
references.pmid: 1423616
references.citation: Nat Rev Cancer. 2012 Sep;12(9):613-26
references.pmid: 22898542
references.citation: Genes Dev. 1999 Oct 15;13(20):2658-69
references.pmid: 10541552
references.citation: FEBS Lett. 2009 Sep 3;583(17):2710-4
references.pmid: 19619542
references.citation: Oncogene. 2008 Nov 6;27(52):6657-66
references.pmid: 18711402
references.citation: Genes Dev. 1997 Mar 15;11(6):714-25
references.pmid: 9087426
references.citation: Nat Struct Mol Biol. 2010 Nov;17(11):1358-66
references.pmid: 20972445
references.citation: Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12009-14
references.pmid: 14507994
references.citation: Clin Cancer Res. 2012 Aug 15;18(16):4325-33
references.pmid: 22733537
references.citation: Cancer Res. 2006 Oct 1;66(19):9502-8
references.pmid: 17018606
references.citation: Pathol Int. 2000 Oct;50(10):786-92
references.pmid: 11107050
references.citation: Int J Cancer. 2001 May 20;95(3):168-75
references.pmid: 11307150
references.citation: J Biol Chem. 1994 Dec 23;269(51):32672-7
references.pmid: 7798274
references.citation: Proc Natl Acad Sci U S A. 1997 Jun 10;94(12):6048-53
references.pmid: 9177166
references.citation: Nat Commun. 2013;4:2996
references.pmid: 24356649
references.citation: Cell. 1992 Jun 26;69(7):1237-45
references.pmid: 1535557
references.citation: Mol Cell Biol. 2011 Dec;31(24):4928-37
references.pmid: 21986500
references.citation: Mol Cell. 2007 Jun 8;26(5):745-52
references.pmid: 17540599
references.citation: Mol Cell Biol. 2006 Oct;26(19):7269-82
references.pmid: 16980628
references.citation: Mol Cell Biol. 1999 Jan;19(1):12-20
references.pmid: 9858527
references.citation: Science. 1998 Nov 20;282(5393):1497-501
references.pmid: 9822382
references.citation: FEBS Lett. 1997 Dec 22;420(1):25-7
references.pmid: 9450543
references.citation: Cancer Res. 2006 Oct 1;66(19):9467-73
references.pmid: 17018602
references.citation: Cell. 2009 May 1;137(3):413-31
references.pmid: 19410540
references.citation: Cell Cycle. 2007 Jul 1;6(13):1586-93
references.pmid: 17554199
references.citation: Science. 2000 May 12;288(5468):1053-8
references.pmid: 10807576
references.citation: Front Biosci (Landmark Ed). 2009 Jan 01;14:2647-56
references.pmid: 19273224
references.citation: Cell. 2008 May 16;133(4):612-26
references.pmid: 18485870
references.citation: J Cell Biochem. 2003 Jun 1;89(3):563-75
references.pmid: 12761890
references.citation: Int J Biol Sci. 2012;8(5):672-84
references.pmid: 22606048
references.citation: Nature. 1995 Jun 22;375(6533):694-8
references.pmid: 7791904
references.citation: PLoS One. 2012;7(9):e46148
references.pmid: 23029416
references.citation: Oncogene. 2001 Jul 5;20(30):4041-9
references.pmid: 11494132
references.citation: EMBO J. 1996 Oct 1;15(19):5349-57
references.pmid: 8895579
references.citation: Nat Rev Mol Cell Biol. 2008 Sep;9(9):702-12
references.pmid: 18719709
references.citation: J Biomed Biotechnol. 2011;2011:876173
references.pmid: 21541195
references.citation: Int J Cancer. 2001 Jun 15;92(6):790-6
references.pmid: 11351297
references.citation: Cancer Res. 2008 Dec 15;68(24):10094-104
references.pmid: 19074875
references.citation: Dis Model Mech. 2009 Jan-Feb;2(1-2):47-55
references.pmid: 19132120
references.citation: J Mol Med (Berl). 2008 May;86(5):585-96
references.pmid: 18335186
references.citation: Mol Cell. 2007 Jun 8;26(5):731-43
references.pmid: 17540598
references.citation: Nature. 1992 Jul 2;358(6381):15-6
references.pmid: 1614522
references.citation: Cell Cycle. 2004 Apr;3(4):472-8
references.pmid: 14739777
references.citation: J Biol Chem. 2009 May 22;284(21):13987-4000
references.pmid: 19321440
references.citation: EMBO J. 2002 Aug 1;21(15):4037-48
references.pmid: 12145204
references.citation: J Pathol. 1999 Jul;188(3):322-8
references.pmid: 10419603
references.citation: Nature. 1993 Apr 29;362(6423):857-60
references.pmid: 8479525
references.citation: Mol Cell Biol. 1995 Jun;15(6):3032-40
references.pmid: 7539102
references.citation: Oncol Res. 2001;12(11-12):451-7
references.pmid: 11939408
references.citation: J Biol Chem. 2003 Oct 3;278(40):38315-24
references.pmid: 12874296
references.citation: Nature. 1997 May 15;387(6630):299-303
references.pmid: 9153396
references.citation: PLoS One. 2013 Oct 11;8(10):e77643
references.pmid: 24147044
references.citation: Cell. 1997 Oct 31;91(3):325-34
references.pmid: 9363941
references.citation: Trends Cell Biol. 2010 May;20(5):299-309
references.pmid: 20172729
references.citation: Blood. 2002 May 1;99(9):3367-75
references.pmid: 11964305
references.citation: Cell. 1993 Nov 19;75(4):817-25
references.pmid: 8242752
references.citation: Histol Histopathol. 2012 Apr;27(4):437-43
references.pmid: 22374721
references.citation: J Mol Cell Biol. 2011 Feb;3(1):44-50
references.pmid: 21278451
references.citation: J Biol Chem. 2003 Nov 14;278(46):45946-53
references.pmid: 12963717
references.citation: Nat Rev Cancer. 2013 Feb;13(2):83-96
references.pmid: 23303139
references.citation: Genes Dev. 1995 Apr 15;9(8):935-44
references.pmid: 7774811
references.citation: Int J Cancer. 2005 Nov 10;117(3):469-75
references.pmid: 15906355
references.citation: J Biol Chem. 1999 Dec 31;274(53):38189-96
references.pmid: 10608892
references.citation: Mol Cell. 2001 Mar;7(3):683-94
references.pmid: 11463392
references.citation: Int J Cancer. 1999 Mar 15;80(6):930-4
references.pmid: 10074928
references.citation: Mol Cell. 1997 Dec;1(1):3-11
references.pmid: 9659898
references.citation: Cell Death Differ. 2006 Jun;13(6):951-61
references.pmid: 16575405
references.citation: Cancer Cell. 2009 May 5;15(5):363-75
references.pmid: 19411066
references.citation: Mol Cell Biol. 2004 Jul;24(13):5835-43
references.pmid: 15199139
references.citation: Oncogene. 1998 Dec 24;17(25):3287-99
references.pmid: 9916991
references.citation: Nat Cell Biol. 2008 Feb;10(2):138-48
references.pmid: 18204439
references.citation: Proc Natl Acad Sci U S A. 1998 Dec 22;95(26):15608-12
references.pmid: 9861017
references.citation: Oncogene. 2006 Apr 27;25(18):2565-74
references.pmid: 16331255
references.citation: Nature. 2007 Jun 28;447(7148):1130-4
references.pmid: 17554337
references.citation: Cancer Res. 2001 Apr 1;61(7):3212-9
references.pmid: 11306511
references.citation: Cancer Res. 1998 Feb 15;58(4):609-13
references.pmid: 9485008
references.citation: Genes Cancer. 2012 Mar;3(3-4):274-82
references.pmid: 23150760
references.citation: Neoplasia. 2013 Sep;15(9):1049-63
references.pmid: 24027430
references.citation: Cell. 1995 Jan 27;80(2):293-9
references.pmid: 7834749
references.citation: Oncogene. 2012 Mar 15;31(11):1342-53
references.pmid: 21822304
references.citation: Mol Cancer. 2011 Sep 12;10:111
references.pmid: 21910853
references.citation: Int J Oncol. 2001 Sep;19(3):625-32
references.pmid: 11494046
references.citation: FEBS Lett. 1999 Mar 19;447(1):5-9
references.pmid: 10218570
references.citation: Nature. 1997 May 15;387(6630):296-9
references.pmid: 9153395
references.citation: J Biol Chem. 2004 Feb 6;279(6):4877-86
references.pmid: 14612455
references.citation: Proc Natl Acad Sci U S A. 2011 Jul 19;108(29):12001-6
references.pmid: 21730163
references.citation: Nat Cell Biol. 2006 Aug;8(8):855-62
references.pmid: 16845383
references.citation: EMBO J. 2003 Dec 1;22(23):6365-77
references.pmid: 14633995
references.citation: EMBO J. 1991 Jun;10(6):1565-9
references.pmid: 2026149