• Aucun résultat trouvé

L’invalidation d’Api5 chez la souris est létale in utero.

CONCLUSIONS, DISCUSSIONS,

V. L’invalidation d’Api5 chez la souris est létale in utero.

La réalisation du KO d’Api5 chez la souris nous a permis de montrer que la perte homozygote d’Api5 entraîne une létalité embryonnaire qui survient à des stades précoces de la gestation (avant E6). Le stade exact de la létalité et le phénotype des embryons homozygotes API5 / n’ont pas été déterminées. Malheureusement, j’ai été confrontée à des limites techniques pour le travail avec des embryons aux premiers stades de développement.

Cependant le résultat obtenu nous permet d’ores et déjà de souligner l’importance de la fonction d’Api5 dans la prolifération cellulaire et ainsi qu’une absence de redondance

fonctionnelle, qui pourrait compenser sa perte. En effet, la létalité embryonnaire des souris KO est un événement observé mais rare, en raison de la redondance de fonction retrouvée au sein des familles de protéines mammifères. En mode d’illustration, les KO chez la souris d’E2F1 (et du reste des E2Fs sauf pour E2F3, Table 5), du FGF2 et de la plupart des Cyclines et Cdks (longtemps considérées comme des régulateurs clés et essentiels du cycle cellulaire) sont viables (Chen et al, 2009; Malumbres & Barbacid, 2009; Satyanarayana & Kaldis, 2009). La létalité du KO d’une protéine à un stade embryonnaire précoce souligne le caractère essentiel de son rôle dans la prolifération, dans le maintien de l’intégrité génétique ou dans l’embryogenèse au cours des premiers stades de développement. L’extraordinaire conservation de la séquence protéique d’Api5 au cours de l’évolution (Figure 40) est un argument additionnel à faveur du caractère essentiel de la protéine.

Figure 40. La séquence de la protéine Api5 est extrêmement conservée au cours de l’évolution. Alignement in silico à l’aide du logiciel «PRALINE» des séquences protéiques d’Api5 de six différentes espèces (Simossis & Heringa, 2005). Du haut au bas : Homo sapiens (Api5 524aa), Mus musculus (Api5 524aa), Galllus gallus (Api5 524aa), Xenopus laevis (Api5 524aa), Bos taurus (Api5 504aa) et Drosophila melanogaster (Api5 536aa). L’échelle de couleurs indiquant la conservation des acides aminés apparaît en haut de l’alignement.

De plus, les données bibliographiques et nos résultats montrent qu’Api5 joue une fonction modulatrice de l’activité pro mitotique et pro apoptotique du facteur de transcription E2F1 (Morris et al, 2006). Il est intéressant de constater que le KO de pRb chez la souris (le régulateur de l’activité E2F par excellence) est létal au stade embryonnaire, tout comme celui d’Api5 (Clarke et al, 1992; Jacks et al, 1992; Lee et al, 1992). Cependant, les embryons invalidés pour pRb meurent à mi gestation en raison d’une apoptose massive. Nous pouvons donc penser que les défauts présents dans les embryons invalidés pour Api5 ne sont pas provoqués par l’absence de son activité anti apoptotique, car dans ce cas nous aurions eu un phénotype similaire à celui de la souris KO pour pRb. La létalité de l’invalidation d’Api5 serait donc à mettre en relation avec son rôle d’activateur au niveau du cycle cellulaire. Dans ce sens, le KO de la kinase Cdk1, enzyme clé du cycle cellulaire, ainsi que les KO de ses deux régulateurs : les Cyclines A2 et B1, sont létaux chez la souris à des stades embryonnaires précoces (Brandeis et al, 1998; Murphy et al, 1997; Santamaria et al, 2007).

En conclusion, cette étude a traité de la fonction d’Api5, protéine modulatrice de l’activité du facteur de transcription d’E2F1. La protéine Api5, tout comme sa cible E2F1, est une protéine aux fonctions ambigües impliquées à la fois dans le déclenchement du cycle cellulaire et de l’apoptose en fonction du contexte cellulaire. La découverte du mécanisme moléculaire par lequel Api5 exerce sa régulation sur l’activité d’E2F1 me semble l’étape suivante impérative à la compréhension de la fonction d’Api5. De part son activité anti apoptotique décrite dans la bibliographie et son activité pro mitotique décrite dans ce travail, Api5 peut être considéré comme un proto oncogène impliqué dans la progression tumorale quand son expression ou son activité sont dérégulées. En illustration, Api5 est retrouvé surexprimé, ainsi qu’associé à une résistance au traitement et à des mauvais pronostics dans de nombreuses pathologies cancéreuses. Cependant, avec la réalisation du KO d’Api5 chez la souris, il apparaît qu’Api5 n’est pas seulement impliqué dans la progression tumorale dans un contexte pathologique, mais désormais Api5 doit être considéré et étudié en tant que régulateur essentiel à la prolifération et au développement embryonnaires.

Alonso MM, Fueyo J, Shay JW, Aldape KD, Jiang H, Lee OH, Johnson DG, Xu J, Kondo Y, Kanzawa T, Kyo S, Bekele BN, Zhou X, Nigro J, McDonald JM, Yung WK, Gomez Manzano C (2005) Expression of transcription factor E2F1 and telomerase in glioblastomas: mechanistic linkage and prognostic significance. J Natl Cancer Inst 97: 1589 1600

Arnaud E, Touriol C, Boutonnet C, Gensac MC, Vagner S, Prats H, Prats AC (1999) A new 34 kilodalton isoform of human fibroblast growth factor 2 is cap dependently synthesized by using a non AUG start codon and behaves as a survival factor. Mol Cell Biol 19: 505 514

Asano M, Nevins JR, Wharton RP (1996) Ectopic E2F expression induces S phase and apoptosis in Drosophila imaginal discs. Genes Dev 10: 1422 1432

Aune GJ, Takagi K, Sordet O, Guirouilh Barbat J, Antony S, Bohr VA, Pommier Y (2008) Von Hippel Lindau coupled and transcription coupled nucleotide excision repair dependent degradation of RNA polymerase II in response to trabectedin. Clin Cancer Res 14: 6449 6455 Bagchi A, Mills AA (2008) The quest for the 1p36 tumor suppressor. Cancer Res 68: 2551 2556

Balciunaite E, Spektor A, Lents NH, Cam H, Te Riele H, Scime A, Rudnicki MA, Young R, Dynlacht BD (2005) Pocket protein complexes are recruited to distinct targets in quiescent and proliferating cells. Mol Cell Biol 25: 8166 8178

Bandara LR, Buck VM, Zamanian M, Johnston LH, La Thangue NB (1993) Functional synergy between DP 1 and E2F 1 in the cell cycle regulating transcription factor DRTF1/E2F. EMBO J

12: 4317 4324

Bartek J, Bartkova J, Lukas J (1996) The retinoblastoma protein pathway and the restriction point. Curr Opin Cell Biol 8: 805 814

Bartek J, Lukas J (2003) Chk1 and Chk2 kinases in checkpoint control and cancer. Cancer Cell

3: 421 429

Bates S, Phillips AC, Clark PA, Stott F, Peters G, Ludwig RL, Vousden KH (1998) p14ARF links the tumour suppressors RB and p53. Nature 395: 124 125

Bell LA, Ryan KM (2004) Life and death decisions by E2F 1. Cell Death Differ 11: 137 142 Ben Shachar B, Feldstein O, Hacohen D, Ginsberg D (2010) The tumor suppressor maspin mediates E2F1 induced sensitivity of cancer cells to chemotherapy. Mol Cancer Res 8: 363 372

Berkovich E, Ginsberg D (2003) ATM is a target for positive regulation by E2F 1. Oncogene 22: 161 167

Bianchini M, Martinelli G, Renzulli M, Gonzalez Cid M, Larripa I (2007) cDNA microarray study to identify expression changes relevant for apoptosis in K562 cells co treated with amifostine and imatinib. Cancer Chemother Pharmacol 59: 349 360

Bieda M, Xu X, Singer MA, Green R, Farnham PJ (2006) Unbiased location analysis of E2F1 binding sites suggests a widespread role for E2F1 in the human genome. Genome Res 16: 595 605

Bindra RS, Glazer PM (2006) Basal repression of BRCA1 by multiple E2Fs and pocket proteins at adjacent E2F sites. Cancer Biol Ther 5: 1400 1407

Bindra RS, Glazer PM (2007) Repression of RAD51 gene expression by E2F4/p130 complexes in hypoxia. Oncogene 26: 2048 2057

Blais A, Monte D, Pouliot F, Labrie C (2002) Regulation of the human cyclin dependent kinase inhibitor p18INK4c by the transcription factors E2F1 and Sp1. J Biol Chem 277: 31679 31693 Blake MC, Azizkhan JC (1989) Transcription factor E2F is required for efficient expression of the hamster dihydrofolate reductase gene in vitro and in vivo. Mol Cell Biol 9: 4994 5002 Blattner C, Sparks A, Lane D (1999) Transcription factor E2F 1 is upregulated in response to DNA damage in a manner analogous to that of p53. Mol Cell Biol 19: 3704 3713

Bouchard C, Thieke K, Maier A, Saffrich R, Hanley Hyde J, Ansorge W, Reed S, Sicinski P, Bartek J, Eilers M (1999) Direct induction of cyclin D2 by Myc contributes to cell cycle progression and sequestration of p27. EMBO J 18: 5321 5333

Bracken AP, Ciro M, Cocito A, Helin K (2004) E2F target genes: unraveling the biology. Trends Biochem Sci 29: 409 417

Braithwaite AW, Del Sal G, Lu X (2006) Some p53 binding proteins that can function as arbiters of life and death. Cell Death Differ 13: 984 993

Brandeis M, Rosewell I, Carrington M, Crompton T, Jacobs MA, Kirk J, Gannon J, Hunt T (1998) Cyclin B2 null mice develop normally and are fertile whereas cyclin B1 null mice die in utero. Proc Natl Acad Sci U S A 95: 4344 4349

Bug M, Dobbelstein M (2011) Anthracyclines induce the accumulation of mutant p53 through E2F1 dependent and independent mechanisms. Oncogene 30: 3612 3624

Campanero MR, Flemington EK (1997) Regulation of E2F through ubiquitin proteasome dependent degradation: stabilization by the pRB tumor suppressor protein. Proc Natl Acad Sci U S A 94: 2221 2226

Cao Q, Xia Y, Azadniv M, Crispe IN (2004) The E2F 1 transcription factor promotes caspase 8 and bid expression, and enhances Fas signaling in T cells. J Immunol 173: 1111 1117

Carcagno AL, Ogara MF, Sonzogni SV, Marazita MC, Sirkin PF, Ceruti JM, Canepa ET (2009) E2F1 transcription is induced by genotoxic stress through ATM/ATR activation. IUBMB Life

Ceol CJ, Horvitz HR (2001) dpl 1 DP and efl 1 E2F act with lin 35 Rb to antagonize Ras signaling in C. elegans vulval development. Mol Cell 7: 461 473

Chellappan SP, Hiebert S, Mudryj M, Horowitz JM, Nevins JR (1991) The E2F transcription factor is a cellular target for the RB protein. Cell 65: 1053 1061

Chen HZ, Tsai SY, Leone G (2009) Emerging roles of E2Fs in cancer: an exit from cell cycle control. Nat Rev Cancer 9: 785 797

Chen Q, Hung FC, Fromm L, Overbeek PA (2000) Induction of cell cycle entry and cell death in postmitotic lens fiber cells by overexpression of E2F1 or E2F2. Invest Ophthalmol Vis Sci 41: 4223 4231

Choudhary C, Kumar C, Gnad F, Nielsen ML, Rehman M, Walther TC, Olsen JV, Mann M (2009) Lysine acetylation targets protein complexes and co regulates major cellular functions. Science 325: 834 840

Christensen J, Cloos P, Toftegaard U, Klinkenberg D, Bracken AP, Trinh E, Heeran M, Di Stefano L, Helin K (2005) Characterization of E2F8, a novel E2F like cell cycle regulated repressor of E2F activated transcription. Nucleic Acids Res 33: 5458 5470

Clarke AR, Maandag ER, van Roon M, van der Lugt NM, van der Valk M, Hooper ML, Berns A, te Riele H (1992) Requirement for a functional Rb 1 gene in murine development. Nature 359: 328 330

Cohen Jonathan E, Toulas C, Monteil S, Couderc B, Maret A, Bard JJ, Prats H, Daly Schveitzer N, Favre G (1997) Radioresistance induced by the high molecular forms of the basic fibroblast growth factor is associated with an increased G2 delay and a hyperphosphorylation of p34CDC2 in HeLa cells. Cancer Res 57: 1364 1370

Conner EA, Lemmer ER, Omori M, Wirth PJ, Factor VM, Thorgeirsson SS (2000) Dual functions of E2F 1 in a transgenic mouse model of liver carcinogenesis. Oncogene 19: 5054 5062

Cooper CS, Nicholson AG, Foster C, Dodson A, Edwards S, Fletcher A, Roe T, Clark J, Joshi A, Norman A, Feber A, Lin D, Gao Y, Shipley J, Cheng SJ (2006) Nuclear overexpression of the E2F3 transcription factor in human lung cancer. Lung Cancer 54: 155 162

Costanzo M, Nishikawa JL, Tang X, Millman JS, Schub O, Breitkreuz K, Dewar D, Rupes I, Andrews B, Tyers M (2004) CDK activity antagonizes Whi5, an inhibitor of G1/S transcription in yeast. Cell 117: 899 913

Couderc B, Prats H, Bayard F, Amalric F (1991) Potential oncogenic effects of basic fibroblast growth factor requires cooperation between CUG and AUG initiated forms. Cell Regul 2: 709 718

Dai JM, Wang ZY, Sun DC, Lin RX, Wang SQ (2007) SIRT1 interacts with p73 and suppresses p73 dependent transcriptional activity. J Cell Physiol 210: 161 166

Dannenberg JH, van Rossum A, Schuijff L, te Riele H (2000) Ablation of the retinoblastoma gene family deregulates G(1) control causing immortalization and increased cell turnover under growth restricting conditions. Genes Dev 14: 3051 3064

DeGregori J (2002) The genetics of the E2F family of transcription factors: shared functions and unique roles. Biochim Biophys Acta 1602: 131 150

DeGregori J, Johnson DG (2006) Distinct and Overlapping Roles for E2F Family Members in Transcription, Proliferation and Apoptosis. Curr Mol Med 6: 739 748

DeGregori J, Leone G, Miron A, Jakoi L, Nevins JR (1997) Distinct roles for E2F proteins in cell growth control and apoptosis. Proc Natl Acad Sci U S A 94: 7245 7250

DeGregori J, Leone G, Ohtani K, Miron A, Nevins JR (1995) E2F 1 accumulation bypasses a G1 arrest resulting from the inhibition of G1 cyclin dependent kinase activity. Genes Dev 9: 2873 2887

Di Stefano L, Jensen MR, Helin K (2003) E2F7, a novel E2F featuring DP independent repression of a subset of E2F regulated genes. EMBO J 22: 6289 6298

Dick FA, Dyson N (2003) pRB contains an E2F1 specific binding domain that allows E2F1 induced apoptosis to be regulated separately from other E2F activities. Mol Cell 12: 639 649 Dijkers PF, Medema RH, Lammers JW, Koenderman L, Coffer PJ (2000) Expression of the pro apoptotic Bcl 2 family member Bim is regulated by the forkhead transcription factor FKHR L1. Curr Biol 10: 1201 1204

Dimova DK, Dyson NJ (2005) The E2F transcriptional network: old acquaintances with new faces. Oncogene 24: 2810 2826

Dimri R, Sharabi Y, Shoham J (2000) Specific inhibition of glucocorticoid induced thymocyte apoptosis by substance P. J Immunol 164: 2479 2486

Du W, Vidal M, Xie JE, Dyson N (1996) RBF, a novel RB related gene that regulates E2F activity and interacts with cyclin E in Drosophila. Genes Dev 10: 1206 1218

Dynlacht BD, Brook A, Dembski M, Yenush L, Dyson N (1994) DNA binding and trans activation properties of Drosophila E2F and DP proteins. Proc Natl Acad Sci U S A 91: 6359 6363

Dynlacht BD, Moberg K, Lees JA, Harlow E, Zhu L (1997) Specific regulation of E2F family members by cyclin dependent kinases. Mol Cell Biol 17: 3867 3875

Eischen CM, Packham G, Nip J, Fee BE, Hiebert SW, Zambetti GP, Cleveland JL (2001) Bcl 2 is an apoptotic target suppressed by both c Myc and E2F 1. Oncogene 20: 6983 6993

Ekholm SV, Reed SI (2000) Regulation of G(1) cyclin dependent kinases in the mammalian cell cycle. Curr Opin Cell Biol 12: 676 684

Elsayed YA, Sausville EA (2001) Selected novel anticancer treatments targeting cell signaling proteins. Oncologist 6: 517 537

Engelmann D, Knoll S, Ewerth D, Steder M, Stoll A, Putzer BM (2010) Functional interplay between E2F1 and chemotherapeutic drugs defines immediate E2F1 target genes crucial for cancer cell death. Cell Mol Life Sci 67: 931 948

Engelmann D, Putzer BM (2010) Translating DNA damage into cancer cell death A roadmap for E2F1 apoptotic signalling and opportunities for new drug combinations to overcome chemoresistance. Drug Resist Updat 13: 119 131

Evans T, Rosenthal ET, Youngblom J, Distel D, Hunt T (1983) Cyclin: a protein specified by maternal mRNA in sea urchin eggs that is destroyed at each cleavage division. Cell 33: 389 396

Eymin B, Gazzeri S, Brambilla C, Brambilla E (2001a) Distinct pattern of E2F1 expression in human lung tumours: E2F1 is upregulated in small cell lung carcinoma. Oncogene 20: 1678 1687

Eymin B, Karayan L, Seite P, Brambilla C, Brambilla E, Larsen CJ, Gazzeri S (2001b) Human ARF binds E2F1 and inhibits its transcriptional activity. Oncogene 20: 1033 1041

Fagan R, Flint KJ, Jones N (1994) Phosphorylation of E2F 1 modulates its interaction with the retinoblastoma gene product and the adenoviral E4 19 kDa protein. Cell 78: 799 811

Faye A, Poyet JL (2010) Targeting AAC 11 in cancer therapy. Expert Opin Ther Targets 14: 57 65

Field SJ, Tsai FY, Kuo F, Zubiaga AM, Kaelin WG, Jr., Livingston DM, Orkin SH, Greenberg ME (1996) E2F 1 functions in mice to promote apoptosis and suppress proliferation. Cell 85: 549 561

Forozan F, Veldman R, Ammerman CA, Parsa NZ, Kallioniemi A, Kallioniemi OP, Ethier SP (1999) Molecular cytogenetic analysis of 11 new breast cancer cell lines. Br J Cancer 81: 1328 1334

Fortin A, MacLaurin JG, Arbour N, Cregan SP, Kushwaha N, Callaghan SM, Park DS, Albert PR, Slack RS (2004) The proapoptotic gene SIVA is a direct transcriptional target for the tumor suppressors p53 and E2F1. J Biol Chem 279: 28706 28714

Frolov MV, Huen DS, Stevaux O, Dimova D, Balczarek Strang K, Elsdon M, Dyson NJ (2001) Functional antagonism between E2F family members. Genes Dev 15: 2146 2160

Furukawa T, Sunamura M, Horii A (2006) Molecular mechanisms of pancreatic carcinogenesis. Cancer Sci 97: 1 7

Furukawa Y, Nishimura N, Satoh M, Endo H, Iwase S, Yamada H, Matsuda M, Kano Y, Nakamura M (2002) Apaf 1 is a mediator of E2F 1 induced apoptosis. J Biol Chem 277: 39760 39768

Gage JR, Meyers C, Wettstein FO (1990) The E7 proteins of the nononcogenic human papillomavirus type 6b (HPV 6b) and of the oncogenic HPV 16 differ in retinoblastoma protein binding and other properties. J Virol 64: 723 730

Galbiati L, Mendoza Maldonado R, Gutierrez MI, Giacca M (2005) Regulation of E2F 1 after DNA damage by p300 mediated acetylation and ubiquitination. Cell Cycle 4: 930 939

Garmy Susini B, Delmas E, Gourdy P, Zhou M, Bossard C, Bugler B, Bayard F, Krust A, Prats AC, Doetschman T, Prats H, Arnal JF (2004) Role of fibroblast growth factor 2 isoforms in the effect of estradiol on endothelial cell migration and proliferation. Circ Res 94: 1301 1309 Gartel AL, Goufman E, Tevosian SG, Shih H, Yee AS, Tyner AL (1998) Activation and repression of p21(WAF1/CIP1) transcription by RB binding proteins. Oncogene 17: 3463 3469

Gaubatz S, Lindeman GJ, Ishida S, Jakoi L, Nevins JR, Livingston DM, Rempel RE (2000) E2F4 and E2F5 play an essential role in pocket protein mediated G1 control. Mol Cell 6: 729 735 Gaubatz S, Wood JG, Livingston DM (1998) Unusual proliferation arrest and transcriptional control properties of a newly discovered E2F family member, E2F 6. Proc Natl Acad Sci U S A

95: 9190 9195

Gauci S, Helbig AO, Slijper M, Krijgsveld J, Heck AJ, Mohammed S (2009) Lys N and trypsin cover complementary parts of the phosphoproteome in a refined SCX based approach. Anal Chem 81: 4493 4501

Geng Y, Yu Q, Sicinska E, Das M, Schneider JE, Bhattacharya S, Rideout WM, Bronson RT, Gardner H, Sicinski P (2003) Cyclin E ablation in the mouse. Cell 114: 431 443

Germain D, Russell A, Thompson A, Hendley J (2000) Ubiquitination of free cyclin D1 is independent of phosphorylation on threonine 286. J Biol Chem 275: 12074 12079

Gianfrancesco F, Esposito T, Ciccodicola A, D'Esposito M, Mazzarella R, D'Urso M, Forabosco A (1999) Molecular cloning and fine mapping of API5L1, a novel human gene strongly related to an antiapoptotic gene. Cytogenet Cell Genet 84: 164 166

Ginsberg D, Vairo G, Chittenden T, Xiao ZX, Xu G, Wydner KL, DeCaprio JA, Lawrence JB, Livingston DM (1994) E2F 4, a new member of the E2F transcription factor family, interacts with p107. Genes Dev 8: 2665 2679

Gomez Manzano C, Mitlianga P, Fueyo J, Lee HY, Hu M, Spurgers KB, Glass TL, Koul D, Liu TJ, McDonnell TJ, Yung WK (2001) Transfer of E2F 1 to human glioma cells results in transcriptional up regulation of Bcl 2. Cancer Res 61: 6693 6697

Goodrich DW, Wang NP, Qian YW, Lee EY, Lee WH (1991) The retinoblastoma gene product regulates progression through the G1 phase of the cell cycle. Cell 67: 293 302

Gould A, Morrison A, Sproat G, White RA, Krumlauf R (1997) Positive cross regulation and enhancer sharing: two mechanisms for specifying overlapping Hox expression patterns. Genes Dev 11: 900 913

Gu Y, Rosenblatt J, Morgan DO (1992) Cell cycle regulation of CDK2 activity by phosphorylation of Thr160 and Tyr15. EMBO J 11: 3995 4005

Gudi R, Barkinge J, Hawkins S, Prabhakar B, Kanteti P (2009) Siva 1 promotes K 48 polyubiquitination of TRAF2 and inhibits TCR mediated activation of NF kappaB. J Environ Pathol Toxicol Oncol 28: 25 38

Guy CT, Zhou W, Kaufman S, Robinson MO (1996) E2F 1 blocks terminal differentiation and causes proliferation in transgenic megakaryocytes. Mol Cell Biol 16: 685 693

Hall M, Peters G (1996) Genetic alterations of cyclins, cyclin dependent kinases, and Cdk inhibitors in human cancer. Adv Cancer Res 68: 67 108

Haller F, Gunawan B, von Heydebreck A, Schwager S, Schulten HJ, Wolf Salgo J, Langer C, Ramadori G, Sultmann H, Fuzesi L (2005) Prognostic role of E2F1 and members of the CDKN2A network in gastrointestinal stromal tumors. Clin Cancer Res 11: 6589 6597

Hallstrom TC, Nevins JR (2003) Specificity in the activation and control of transcription factor E2F dependent apoptosis. Proc Natl Acad Sci U S A 100: 10848 10853

Han S, Park K, Bae BN, Kim KH, Kim HJ, Kim YD, Kim HY (2003) E2F1 expression is related with the poor survival of lymph node positive breast cancer patients treated with fluorouracil, doxorubicin and cyclophosphamide. Breast Cancer Res Treat 82: 11 16

Hanahan D, Weinberg RA (2011) Hallmarks of cancer: the next generation. Cell 144: 646 674 Harbour JW, Luo RX, Dei Santi A, Postigo AA, Dean DC (1999) Cdk phosphorylation triggers sequential intramolecular interactions that progressively block Rb functions as cells move through G1. Cell 98: 859 869

Harper JW, Burton JL, Solomon MJ (2002) The anaphase promoting complex: it's not just for mitosis any more. Genes Dev 16: 2179 2206

Harper JW, Elledge SJ (1996) Cdk inhibitors in development and cancer. Curr Opin Genet Dev

6: 56 64

Hartwell LH, Weinert TA (1989) Checkpoints: controls that ensure the order of cell cycle events. Science 246: 629 634

He Y, Armanious MK, Thomas MJ, Cress WD (2000) Identification of E2F 3B, an alternative form of E2F 3 lacking a conserved N terminal region. Oncogene 19: 3422 3433

Heery DM, Kalkhoven E, Hoare S, Parker MG (1997) A signature motif in transcriptional co activators mediates binding to nuclear receptors. Nature 387: 733 736

Helin K, Harlow E, Fattaey A (1993) Inhibition of E2F 1 transactivation by direct binding of the retinoblastoma protein. Mol Cell Biol 13: 6501 6508

Helin K, Lees JA, Vidal M, Dyson N, Harlow E, Fattaey A (1992) A cDNA encoding a pRB binding protein with properties of the transcription factor E2F. Cell 70: 337 350

Hershko T, Chaussepied M, Oren M, Ginsberg D (2005) Novel link between E2F and p53: proapoptotic cofactors of p53 are transcriptionally upregulated by E2F. Cell Death Differ 12: 377 383

Hershko T, Ginsberg D (2004) Up regulation of Bcl 2 homology 3 (BH3) only proteins by E2F1 mediates apoptosis. J Biol Chem 279: 8627 8634

Hiebert SW, Packham G, Strom DK, Haffner R, Oren M, Zambetti G, Cleveland JL (1995) E2F 1:DP 1 induces p53 and overrides survival factors to trigger apoptosis. Mol Cell Biol 15: 6864 6874

Hofferer M, Wirbelauer C, Humar B, Krek W (1999) Increased levels of E2F 1 dependent DNA binding activity after UV or gamma irradiation. Nucleic Acids Res 27: 491 495

Hofland K, Petersen BO, Falck J, Helin K, Jensen PB, Sehested M (2000) Differential cytotoxic pathways of topoisomerase I and II anticancer agents after overexpression of the E2F 1/DP 1 transcription factor complex. Clin Cancer Res 6: 1488 1497

Holmberg C, Helin K, Sehested M, Karlstrom O (1998) E2F 1 induced p53 independent apoptosis in transgenic mice. Oncogene 17: 143 155

Hovey RM, Chu L, Balazs M, DeVries S, Moore D, Sauter G, Carroll PR, Waldman FM (1998) Genetic alterations in primary bladder cancers and their metastases. Cancer Res 58: 3555 3560

Hsieh JK, Fredersdorf S, Kouzarides T, Martin K, Lu X (1997) E2F1 induced apoptosis requires DNA binding but not transactivation and is inhibited by the retinoblastoma protein through direct interaction. Genes Dev 11: 1840 1852

Hsieh JK, Yap D, O'Connor DJ, Fogal V, Fallis L, Chan F, Zhong S, Lu X (2002) Novel function of the cyclin A binding site of E2F in regulating p53 induced apoptosis in response to DNA damage. Mol Cell Biol 22: 78 93

Hu QJ, Dyson N, Harlow E (1990) The regions of the retinoblastoma protein needed for binding to adenovirus E1A or SV40 large T antigen are common sites for mutations. EMBO J 9: 1147 1155

Huang Y, Ishiko T, Nakada S, Utsugisawa T, Kato T, Yuan ZM (1997) Role for E2F in DNA damage induced entry of cells into S phase. Cancer Res 57: 3640 3643

Hwang HC, Clurman BE (2005) Cyclin E in normal and neoplastic cell cycles. Oncogene 24: 2776 2786

Ianari A, Gallo R, Palma M, Alesse E, Gulino A (2004) Specific role for p300/CREB binding protein associated factor activity in E2F1 stabilization in response to DNA damage. J Biol Chem 279: 30830 30835

Ianari A, Natale T, Calo E, Ferretti E, Alesse E, Screpanti I, Haigis K, Gulino A, Lees JA (2009)