A distinct response to endogenous DNA damage in the development of Nbs1-deficient cortical neurons.
Microcephaly is a clinical characteristic for human nijmegen breakage syndrome (NBS, mutated in NBS1 gene), a chromosomal instability syndrome. However, the underlying molecular pathogenesis remains elusive. In the present study, we demonstrate that neuronal disruption of NBS (Nbn in mice) causes microcephaly characterized by the reduction of cerebral cortex and corpus callosum, recapitulating neuronal anomalies in human NBS. Nbs1-deficient neocortex shows accumulative endogenous DNA damage and defective activation of Ataxia telangiectasia and Rad3-related (ATR)-Chk1 pathway upon DNA damage. Notably, in contrast to massive apoptotic cell death in Nbs1-deficient cerebella, activation of p53 leads to a defective neuroprogenitor proliferation in neocortex, likely via specific persistent induction of hematopoietic zinc finger (Hzf) that preferentially promotes p53-mediated cell cycle arrest whilst inhibiting apoptosis. Moreover, Trp53 mutations substantially rescue the microcephaly in Nbs1-deficient mice. Thus, the present results reveal the first clue that developing neurons at different regions of brain selectively respond to endogenous DNA damage, and underscore an important role for Nbs1 in neurogenesis.
Department of Pathology and Center for Experimental Animal Research, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China.
Rui
R
Li
Yun-Gui
YG
Yang
Yunzhou
Y
Gao
Zhao-Qi
ZQ
Wang
Wei-Min
WM
Tong
D000818:Animals; D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D059447:Cell Cycle Checkpoints; D018797:Cell Cycle Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D003337:Corpus Callosum / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008831:Microcephaly / Q000378:metabolism / Q000473:pathology; D055495:Neurogenesis; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C466108:Nijmegen breakage syndrome 1 protein, mouse; D009687:Nuclear Proteins; D011506:Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C404217:Zfp385 protein, mouse; D011494:Protein Kinases; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse; D017346:Protein Serine-Threonine Kinases