Publication Date:
2009-12-18
Description:
In the established model of mammalian cell cycle control, the retinoblastoma protein (Rb) functions to restrict cells from entering S phase by binding and sequestering E2f activators (E2f1, E2f2 and E2f3), which are invariably portrayed as the ultimate effectors of a transcriptional program that commit cells to enter and progress through S phase. Using a panel of tissue-specific cre-transgenic mice and conditional E2f alleles we examined the effects of E2f1, E2f2 and E2f3 triple deficiency in murine embryonic stem cells, embryos and small intestines. We show that in normal dividing progenitor cells E2f1-3 function as transcriptional activators, but contrary to the current view, are dispensable for cell division and instead are necessary for cell survival. In differentiating cells E2f1-3 function in a complex with Rb as repressors to silence E2f targets and facilitate exit from the cell cycle. The inactivation of Rb in differentiating cells resulted in a switch of E2f1-3 from repressors to activators, leading to the superactivation of E2f responsive targets and ectopic cell divisions. Loss of E2f1-3 completely suppressed these phenotypes caused by Rb deficiency. This work contextualizes the activator versus repressor functions of E2f1-3 in vivo, revealing distinct roles in dividing versus differentiating cells and in normal versus cancer-like cell cycles.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2806193/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2806193/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chong, Jean-Leon -- Wenzel, Pamela L -- Saenz-Robles, M Teresa -- Nair, Vivek -- Ferrey, Antoney -- Hagan, John P -- Gomez, Yorman M -- Sharma, Nidhi -- Chen, Hui-Zi -- Ouseph, Madhu -- Wang, Shu-Huei -- Trikha, Prashant -- Culp, Brian -- Mezache, Louise -- Winton, Douglas J -- Sansom, Owen J -- Chen, Danian -- Bremner, Rod -- Cantalupo, Paul G -- Robinson, Michael L -- Pipas, James M -- Leone, Gustavo -- 5 T32 CA106196-04/CA/NCI NIH HHS/ -- CA098956/CA/NCI NIH HHS/ -- P01CA097189/CA/NCI NIH HHS/ -- R01 CA098956/CA/NCI NIH HHS/ -- R01 CA098956-06A2/CA/NCI NIH HHS/ -- R01CA82259/CA/NCI NIH HHS/ -- R01CA85619/CA/NCI NIH HHS/ -- R01HD04470/HD/NICHD NIH HHS/ -- England -- Nature. 2009 Dec 17;462(7275):930-4. doi: 10.1038/nature08677.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Virology, Immunology and Medical Genetics, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016602" target="_blank"〉PubMed〈/a〉
Keywords:
Alleles
;
Animals
;
Apoptosis
;
Cell Cycle/genetics/physiology
;
*Cell Differentiation
;
Cell Proliferation
;
E2F Transcription Factors/deficiency/genetics/*metabolism
;
E2F1 Transcription Factor/deficiency/genetics/metabolism
;
E2F2 Transcription Factor/deficiency/genetics/metabolism
;
E2F3 Transcription Factor/deficiency/genetics/metabolism
;
Embryo, Mammalian/cytology/metabolism
;
Embryonic Stem Cells/*cytology/*metabolism
;
Female
;
*Gene Expression Regulation
;
Intestine, Small/cytology/metabolism
;
Mice
;
Mice, Transgenic
;
Repressor Proteins/deficiency/genetics/*metabolism
;
Retinoblastoma Protein/deficiency/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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