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The Arabidopsis KAKTUS gene encodes a HECT protein and controls the number of endoreduplication cycles


In animals and plants, many cell types switch from mitotic cycles to endoreduplication cycles during differentiation. Little is known about the way in which the number of endoreduplication cycles is controlled in such endopolyploid cells. In this study we have characterized at the molecular level three mutations in the Arabidopsis gene KAKTUS ( KAK), which were previously shown specifically to repress endoreduplication in trichomes. We show that KAK is also involved in the regulation of the number of endoreduplication cycles in various organs that are devoid of trichomes. KAK encodes a protein with sequence similarity to HECT domain proteins. As this class of proteins is known to be involved in ubiquitin-mediated protein degradation, our finding suggests that the number of endoreduplication cycles that occur in several cell types is controlled by this pathway. The KAK gene defines a monophylogenetic subgroup of HECT proteins that also contain Armadillo-like repeats.

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  1. Andrade M, Petosa C, O’Donoghue S, Muller C, Bork P (2001) Comparison of ARM and HEAT protein repeats. J Mol Biol 309:1–18

  2. Bates PW, Vierstra RD (1999) UPL1 and 2, two 405 kDa ubiquitin-protein ligases from Arabidopsis. Plant J 20:183–195

  3. Blanc G, Barakat A, Guyot R, Cooke R, Delseny M (2000) Extensive duplication and reshuffling in the Arabidopsis genome. Plant Cell 12:1093–1102

  4. Bouchez D, Vittorioso P, Courtial B, Camilleri C (1996) Kanamycin rescue: a simple technique for the recovery of T-DNA flanking sequences. Plant Mol Biol Rep 14:115–123

  5. Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium -mediated transformation of Arabidopsis thaliana. Plant J 16:735–743

  6. Conti E, Uy M, Leighton L, Blobel G, Kuriyan J (1998) Crystallographic analysis of the recognition of a nuclear localization signal by the nuclear import factor karyopherin alpha. Cell 94:193–204

  7. Galbraith DW, Harkins KR, Knapp S (1991) Systemic endopolyploidy in Arabidopsis thaliana. Plant Physiol 96:985–989

  8. Gendreau E, Traas J, Desnos T, Grandjean O, Caboche M, Höfte H (1997) Cellular basis of hypocotyl growth in Arabidopsis thaliana. Plant Physiol 14:295–305

  9. Gendreau E, Orbovic V, Hofte H, Traas J (1999) Gibberellin and ethylene control endoreduplication levels in the Arabidopsis thaliana hypocotyl. Planta 209:513–516

  10. Görlich D (1998) Transport into and out of the cell nucleus. EMBO J 17:2721–2727

  11. Hochstrasser M (1996) Ubiquitin-dependent protein degradation. Annu Rev Genet 30:405–439

  12. Huang L, Kinnucan E, Wang G, Beaudenon S, Howley P, Huibregtse J, Pavletich N (1999) Structure of an E6AP-UbcH7 complex: insights into ubiquitination by the E2-E3 enzyme cascade. Science 286:1321–1326

  13. Huibregtse JM, Scheffner M, Beaudenon S, Howley PM (1995) A family of proteins structurally and functionally related to the E6-AP ubiquitin-protein ligase. Proc Natl Acad Sci USA 92:2563–2567

  14. Hülskamp M, Misera S, Jurgens G (1994) Genetic dissection of trichome cell development in Arabidopsis. Cell 76:555-566

  15. Jacobsen SE, Olszewski NE (1993) Mutations at the SPINDLY locus of Arabidopsis alter gibberellin signal transduction. Plant Cell 5:887–896

  16. Jacobsen SE, Binkowski KA, Olszewski NE (1996) SPINDLY, a tetratricopeptide repeat protein involved in gibberellin signal transduction in Arabidopsis. Proc Natl Acad Sci USA 93:9292–9296

  17. Johnson ES, Ma PC, Ota IM, Varshavsky A (1995) A proteolytic pathway that recognizes ubiquitin as a degradation signal. J Biol Chem 270:17442–17456

  18. Kirik V, Bouyer D, Schobinger U, Bechtold N, Herzog M, Bonneville J-M, Hülskamp M (2001) CPR5 is involved in cell proliferation and cell death control and encodes a novel transmembrane protein. Curr Biol 11:1891–1895

  19. Kobe B (1999) Autoinhibition by an internal nuclear localization signal revealed by the crystal structure of mammalian importin alpha. Nat Struct Biol 6:388–397

  20. Kumar S, Kao WH, Howley PM (1997) Physical interaction between specific E2 and Hect E3 enzymes determines functional cooperativity. J Biol Chem 272:13548–13554

  21. Kwon YT, Reiss Y, Fried VA, Hershko A, Yoon JK, Gonda DK, Sangan P, Copeland NG, Jenkins NA, Varshavsky A (1998) The mouse and human genes encoding the recognition component of the N-end rule pathway. Proc Natl Acad Sci USA 95:7898–7903

  22. Li J, Chory J (1997) A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction. Cell 90:929–938

  23. McCallum CM, Comai L, Greene EA, Henikoff S (2000) Targeting induced local lesions in genomes (TILLING) for plant functional genomics. Plant Physiol 123:439–442

  24. Nefsky B, Beach D (1996) Pub1 acts as an E6-AP-like protein ubiquitiin ligase in the degradation of Cdc25. EMBO J 15:1301–1312

  25. Olszewski NE, Martin FB, Ausubel FM (1988) Specialized binary vector for plant transformation: expression of the Arabidopsis thaliana AHAS gene in Nicotiana tabacum. Nucleic Acids Res 16:10765–10782

  26. Payne CT, Zhang F, Lloyd AM (2000) GL3 encodes a bHLH protein that regulates trichome development in arabidopsis through interaction with GL1 and TTG1. Genetics 156:1349–1362

  27. Peifer M (1996) Regulating cell proliferation: as easy as APC. Science 272:974–975

  28. Perazza D, Vachon G, Herzog M (1998) Gibberellins promote trichome formation by up-regulating GLABROUS1 in Arabidopsis. Plant Physiol 117:375–383

  29. Perazza D, Herzog M, Hülskamp M, Brown S, Dorne AM, Bonneville J-M (1999) Trichome cell growth in Arabidopsis thaliana can be derepressed by mutations in at least five genes. Genetics 152:461–476

  30. Pickart CM (2001) Mechanisms underlyling ubiquitination. Annu Rev Biochem 70:503–533

  31. Rhoads AR, Friedberg F (1997) Sequence motifs for calmodulin recognition. FASEB J 11:331–340

  32. Rotin D (1998) WW (WWP) domains: from structure to function. Curr Top Microbiol Immunol 228:115–133

  33. Scheffner M, Nuber U, Huibregtse JM (1995) Protein ubiquitination involving an E1-E2-E3 enzyme ubiquitin thioester cascade. Nature 373:81–83

  34. Schellmann S, Schnittger A, Kirik V, Wada T, Okada K, Beermann A, Thumfahrt J, Jürgens G, Hülskamp M (2002) TRIPTYCHON and CAPRICE mediate lateral inhibition during trichome and root hair patterning in Arabidopsis. EMBO J 21:5036–5046

  35. Schnittger A, Schobinger U, Bouyer D, Weinl C, Stierhof Y-D, Hülskamp M (2002a) Ectopic D-type cyclin expression induces not only DNA replication but also cell division in Arabidopsis trichomes. Proc Natl Acad Sci USA 99:6410–6415

  36. Schnittger A, Schobinger U, Stierhof Y-D, Hülskamp M (2002b) Ectopic B-type cyclin expression induces mitotic cycles in endoreduplicating Arabidopsis trichomes. Curr Biol 12:415–420.

  37. Schnittger A, Weinl C, Bouyer D, Schobinger U, Hülskamp M (2003) Misexpression of the cyclin-dependent kinase inhibitor ICK1/KRP1 in single-celled Arabidopsis trichomes reduces endoreduplication and cell size and induces cell death. Plant Cell 15:303–315

  38. Sugimoto-Shirasu K, Stacey NJ, Corsar J, Roberts K, McCann MC (2002) DNA topoisomerase VI is essential for endoreduplication in Arabidopsis. Curr Biol 12:1782–1786

  39. Szymanski DB, Lloyd AM, Marks MD (2000) Progress in the molecular genetic analysis of trichome initiation and morphogenesis in Arabidopsis. Trends Plant Sci 5:214–219

  40. Tamai KK, Shimoda C (2002) The novel HECT-type ubiquitin-protein ligase Pub2p shares partially overlapping function with Pub1p in Schizosaccharomyces pombe. J Cell Sci 115:1847–1857

  41. Thornton TM, Kreppel L, Hart G, Olszewski N (1999) Genetic and biochemical analysis of Arabidopsis SPY. In: Altman A, Ziv M, Izhar S (eds) Plant biotechnology and in vitro biology in the 21st century. Kluwer Academic Publishers, Dordrecht, pp 445–448

  42. Traas J, Hülskamp M, Gendreau E, Höfte H (1998) Endoreduplication and development: rule without dividing? Curr Opin Plant Biol 1:498–503

  43. Vierstra RD, Callis J (1999) Polypeptide tags, ubiquitous modifiers for plant protein regulation. Plant Mol Biol 41:435–442

  44. Walker JD, Oppenheimer DG, Concienne J, Larkin JC (2000) SIAMESE, a gene controlling the endoreduplication cell cycle in Arabidopsis thaliana trichomes. Development 127:3931–3940

  45. Xie Y, Varshavsky A (2002) UFD4 lacking the proteasome-binding region catalyses ubiquitination but is impaired in proteolysis. Nat Cell Biol 4:1003–1007

  46. You J, Pickart CM (2001) A HECT domain E3 enzyme assembles novel polyubiquitin chains. J Biol Chem 276:19871–19878

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A.E.R. was the recipient of a fellowship from the Egyptian government. We are indebted to Renaud Blervaque for his help in the kanamycin rescue experiment, to Heda Dolezelova for left border cloning, and to Olivier Catrice for assistance with flow cytometry. We are indebted to the Kazusa DNA Research Institute and to N. Olszewski for plasmids. We also thank Anne Imberty for discussions on protein structures, and Gilles Vachon and Ali Hakimi for critical reading of the manuscript. The experiments described here have been carried out in compliance with French laws governing genetic experimentation

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Correspondence to J.-M. Bonneville.

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Communicated by G. Jürgens

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El Refy, A., Perazza, D., Zekraoui, L. et al. The Arabidopsis KAKTUS gene encodes a HECT protein and controls the number of endoreduplication cycles. Mol Genet Genomics 270, 403–414 (2004).

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  • Endoreduplication
  • Trichome
  • Hypocotyl
  • Cotyledon
  • Ubiquitin E3 ligase