TY - JOUR
T1 - Werner protein protects nonproliferating cells from oxidative DNA damage
AU - Szekely, Anna M.
AU - Bleichert, Franziska
AU - Nümann, Astrid
AU - Van Komen, Stephen
AU - Manasanch, Elisabeth
AU - Ben Nasr, Abdelhakim
AU - Canaan, Allon
AU - Weissman, Sherman M.
PY - 2005/12
Y1 - 2005/12
N2 - Werner syndrome, caused by mutations of the WRN gene, mimics many changes of normal aging. Although roles for WRN protein in DNA replication, recombination, and telomere maintenance have been suggested, the pathology of rapidly dividing cells is not a feature of Werner syndrome. To identify cellular events that are specifically vulnerable to WRN deficiency, we used RNA interference (RNAi) to knockdown WRN or BLM (the RecQ helicase mutated in Bloom syndrome) expression in primary human fibroblasts. Withdrawal of WRN or BLM produced accelerated cellular senescence phenotype and DNA damage response in normal fibroblasts, as evidenced by induction of γH2AX and 53BP1 nuclear foci. After WRN depletion, the induction of these foci was seen most prominently in nondividing cells. Growth in physiological (3%) oxygen or in the presence of an antioxidant prevented the development of the DNA damage foci in WRN-depleted cells, whereas acute oxidative stress led to inefficient repair of the lesions. Furthermore, WRN RNAi-induced DNA damage was suppressed by overexpression of the telomere-binding protein TRF2. These conditions, however, did not prevent the DNA damage response in BLM-ablated cells, suggesting a distinct role for WRN in DNA homeostasis in vivo. Thus, manifestations of Werner syndrome may reflect an impaired ability of slowly dividing cells to limit oxidative DNA damage.
AB - Werner syndrome, caused by mutations of the WRN gene, mimics many changes of normal aging. Although roles for WRN protein in DNA replication, recombination, and telomere maintenance have been suggested, the pathology of rapidly dividing cells is not a feature of Werner syndrome. To identify cellular events that are specifically vulnerable to WRN deficiency, we used RNA interference (RNAi) to knockdown WRN or BLM (the RecQ helicase mutated in Bloom syndrome) expression in primary human fibroblasts. Withdrawal of WRN or BLM produced accelerated cellular senescence phenotype and DNA damage response in normal fibroblasts, as evidenced by induction of γH2AX and 53BP1 nuclear foci. After WRN depletion, the induction of these foci was seen most prominently in nondividing cells. Growth in physiological (3%) oxygen or in the presence of an antioxidant prevented the development of the DNA damage foci in WRN-depleted cells, whereas acute oxidative stress led to inefficient repair of the lesions. Furthermore, WRN RNAi-induced DNA damage was suppressed by overexpression of the telomere-binding protein TRF2. These conditions, however, did not prevent the DNA damage response in BLM-ablated cells, suggesting a distinct role for WRN in DNA homeostasis in vivo. Thus, manifestations of Werner syndrome may reflect an impaired ability of slowly dividing cells to limit oxidative DNA damage.
UR - http://www.scopus.com/inward/record.url?scp=27944477757&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=27944477757&partnerID=8YFLogxK
U2 - 10.1128/MCB.25.23.10492-10506.2005
DO - 10.1128/MCB.25.23.10492-10506.2005
M3 - Article
C2 - 16287861
AN - SCOPUS:27944477757
SN - 0270-7306
VL - 25
SP - 10492
EP - 10506
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 23
ER -