Endocycles

• Verfasst von: Edgar, Bruce [VerfasserIn]
• Verfasst von: Zielke, Norman [VerfasserIn]
• Verfasst von: Gutierrez, Crisanto [VerfasserIn]
• Titel: Endocycles
• Titelzusatz: a recurrent evolutionary innovation for post-mitotic cell growth
• Verf.angabe: Bruce A. Edgar, Norman Zielke and Crisanto Gutierrez
• E-Jahr: 2014
• Jahr: 21 February 2014
• Umfang: 14 S.
• Fussnoten: Gesehen am 12.01.2021
• Titel Quelle: Enthalten in: Nature reviews / Molecular cell biology
• Ort Quelle: London : Macmillan, 2000
• Jahr Quelle: 2014
• Band/Heft Quelle: 15(2014), 3, Seite 197-210
• ISSN Quelle: 1471-0080
• DOI: doi:10.1038/nrm3756
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1744442320

Abstract

Endoreplication occurs in multiple cell types in most animals and plants, typically in terminally differentiated cells. The final level of ploidy is highly cell type- and species-specific.Due to their increased genomic DNA content, endocycling cells can achieve large sizes or massive output of secreted protein products.Endocycle onset requires suppression of mitosis. This is achieved by different mechanisms in different species and cell types. These include transcriptional repression of mitotic cyclin expression, APC/C (anaphase promoting complex, also known as the cyclosome) -mediated degradation of mitotic cyclins and inhibition of cyclin-dependent kinase (CDK) activity. This inhibition often relies on CDK inhibitory proteins.Endoreplication onset and progression are also broadly affected by the activities of the E2F transcription factors and their co-repressors, the RB proteins, which affect the expression of genes involved in mitosis and DNA replication.Endocycle progression involves many of the same factors that control G1-S phase transitions and G1 length in mitotically proliferating cells. Key requirements are the suppression of mitotic CDK (M-CDK) activity, and the retention of oscillating S phase CDK (S-CDK) activity.Various upstream inputs control the speed of endocycling and the timing of endocycle exit. Together these two factors determine final ploidy and also affect cell size. Upstream inputs include nutrients and growth factors, target of rapamycin (TOR) signalling and (in plants) light exposure.Cross-species and cross-kingdom comparisons suggest that endocycles are an ancient cellular innovation that probably evolved many times.