title: p63 and p73 coordinate p53 function to determine the balance between survival, cell death, and senescence in adult neural precursor cells.
abstract: The p53 family members p73 and p63 have been implicated in various aspects of stem cell regulation. Here, we have asked whether they work together to regulate stem cell biology, focusing upon neural precursor cells (NPCs) in the adult murine brain. By studying mice that are haploinsufficient for p63 and/or p73, we show that these two proteins cooperate to ensure appropriate NPC self-renewal and long-term maintenance in the hippocampus and forebrain, and that when both are haploinsufficient, the NPC deficits are significantly greater than haploinsufficiency for either alone. We show that, in the case of p63(+/-) mice, this decrease in adult NPCs is caused by enhanced apoptosis. However, when p73 is coincidently haploinsufficient, this rescues the enhanced apoptosis of p63(+/-) NPCs under both basal conditions and following genotoxic stress, instead causing increased cellular senescence. This increase in cellular senescence is likely due, at least in part, to increased levels of basal DNA damage and p53 activation, as genetic ablation of p53 completely rescues the senescence phenotype observed in p63(+/-); p73(+/-) mice. Thus, the presence of p73 determines whether p63(+/-) NPCs exhibit increased p53-dependent apoptosis or senescence. Together, these studies demonstrate that p63 and p73 cooperate to maintain adult NPC pools through regulation of p53 function; p63 antagonizes p53 to promote cellular survival, whereas p73 regulates self-renewal and p53-mediated apoptosis versus senescence.
authors.affiliation: 1] Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada [2] Institute of Medical Science, Toronto, Ontario, Canada.
authors.forename: M P
authors.initials: MP
authors.lastname: Fatt
authors.affiliation: Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: G I
authors.initials: GI
authors.lastname: Cancino
authors.affiliation: 1] Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada [2] Institute of Medical Science, Toronto, Ontario, Canada [3] Department of Physiology, University of Toronto, Toronto, Ontario, Canada [4] Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: F D
authors.initials: FD
authors.lastname: Miller
authors.affiliation: 1] Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada [2] Institute of Medical Science, Toronto, Ontario, Canada [3] Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D002470:Cell Survival; D016922:Cellular Senescence / Q000235:genetics; D004249:DNA Damage / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D057895:Haploinsufficiency; D006624:Hippocampus / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D058953:Neural Stem Cells / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics*; D016548:Prosencephalon / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics*; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D015534:Trans-Activators; C486419:Trp63 protein, mouse; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins