Changes in chromatin accessibility ensure robust cell cycle exit in terminally differentiated cells
Open Access
- 3 September 2019
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Biology
- Vol. 17 (9), e3000378
- https://doi.org/10.1371/journal.pbio.3000378
Abstract
During terminal differentiation, most cells exit the cell cycle and enter into a prolonged or permanent G0 in which they are refractory to mitogenic signals. Entry into G0 is usually initiated through the repression of cell cycle gene expression by formation of a transcriptional repressor complex called dimerization partner (DP), retinoblastoma (RB)-like, E2F and MuvB (DREAM). However, when DREAM repressive function is compromised during terminal differentiation, additional unknown mechanisms act to stably repress cycling and ensure robust cell cycle exit. Here, we provide evidence that developmentally programmed, temporal changes in chromatin accessibility at a small subset of critical cell cycle genes act to enforce cell cycle exit during terminal differentiation in the Drosophila melanogaster wing. We show that during terminal differentiation, chromatin closes at a set of pupal wing enhancers for the key rate-limiting cell cycle regulators Cyclin E (cycE), E2F transcription factor 1 (e2f1), and string (stg). This closing coincides with wing cells entering a robust postmitotic state that is strongly refractory to cell cycle reactivation, and the regions that close contain known binding sites for effectors of mitogenic signaling pathways such as Yorkie and Notch. When cell cycle exit is genetically disrupted, chromatin accessibility at cell cycle genes remains unaffected, and the closing of distal enhancers at cycE, e2f1, and stg proceeds independent of the cell cycling status. Instead, disruption of cell cycle exit leads to changes in accessibility and expression of a subset of hormone-induced transcription factors involved in the progression of terminal differentiation. Our results uncover a mechanism that acts as a cell cycle–independent timer to limit the response to mitogenic signaling and aberrant cycling in terminally differentiating tissues. In addition, we provide a new molecular description of the cross talk between cell cycle exit and terminal differentiation during metamorphosis.Funding Information
- National Institutes of Health (GM127367)
- National Institutes of Health (GM128851)
- American Cancer Society (RSG-15-161-01-DDC)
This publication has 93 references indexed in Scilit:
- Genome-wide Association of Yorkie with Chromatin and Chromatin-Remodeling ComplexesCell Reports, 2013
- Dissecting the mechanisms of Notch induced hyperplasiaThe EMBO Journal, 2012
- Integrative genomics viewerNature Biotechnology, 2011
- Transcript assembly and quantification by RNA-Seq reveals unannotated transcripts and isoform switching during cell differentiationNature Biotechnology, 2010
- Molecular Maps of the Reorganization of Genome-Nuclear Lamina Interactions during DifferentiationMolecular Cell, 2010
- Retinoids Regulate a Developmental Checkpoint for Tissue Regeneration in DrosophilaCurrent Biology, 2010
- Cell rearrangement and cell division during the tissue level morphogenesis of evaginating Drosophila imaginal discsDevelopmental Biology, 2008
- E2F-associated chromatin modifiers and cell cycle controlCurrent Opinion in Cell Biology, 2007
- Differentiated Horizontal Interneurons Clonally Expand to Form Metastatic Retinoblastoma in MiceCell, 2007
- Coordination of Growth and Cell Division in the Drosophila WingCell, 1998