title: Endocycles: a recurrent evolutionary innovation for post-mitotic cell growth.
abstract: In endoreplication cell cycles, known as endocycles, cells successively replicate their genomes without segregating chromosomes during mitosis and thereby become polyploid. Such cycles, for which there are many variants, are widespread in protozoa, plants and animals. Endocycling cells can achieve ploidies of >200,000 C (chromatin-value); this increase in genomic DNA content allows a higher genomic output, which can facilitate the construction of very large cells or enhance macromolecular secretion. These cells execute normal S phases, using a G1-S regulatory apparatus similar to the one used by mitotic cells, but their capability to segregate chromosomes has been suppressed, typically by downregulation of mitotic cyclin-dependent kinase activity. Endocycles probably evolved many times, and the various endocycle mechanisms found in nature highlight the versatility of the cell cycle control machinery.
authors.affiliation: German Cancer Research Center-Center for Molecular Biology Heidelberg Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Edgar
authors.affiliation: German Cancer Research Center-Center for Molecular Biology Heidelberg Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
authors.forename: Norman
authors.initials: N
authors.lastname: Zielke
authors.affiliation: Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Crisanto
authors.initials: C
authors.lastname: Gutierrez
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D002453:Cell Cycle / Q000235:genetics*; D048708:Cell Growth Processes / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D008938:Mitosis; D011003:Ploidies