RT Journal Article
ID 09e3973962e8528c
A1 Serakinci, Nedime
A1 Cankaya, Tufan
A1 Kølvraa, Steen 
T1 Localization of the Werner Protein Together with H2AX in γ-Irradiation-Induced Neoplastic Transformed Human Mesenchymal Stem Cells
JF Critical Reviews™ in Eukaryotic Gene Expression
JO CRE
YR 2017
FD 2017-04-14
VO 27
IS 1
SP 91
OP 97
K1 telomere
K1 WRN
K1 H2AX
K1 hTERT
K1 hMSC-telo1
K1 irradiation
K1 localization
AB The H2A histone family, member X (H2AX), and Werner (WRN) are important proteins for genome and telomere maintenance. WRN has a major role in genome stability, particularly during DNA replication, transcription, recombination, and repair of DNA double-stranded breaks (DSBs) via base excision repair, homologous recombination, or nonhomologous end joining. H2AX plays a part in the rapid, sensitive, cellular response to the ionizing radiation or DNA-damaging chemotherapeutic agents that cause DSBs. This occurs when radiation-induced DSBs trigger the activation of H2AX and begin the damage-repair process. In this study, we investigate the role and localization of WRN together with DNA damage marker H2AX at the radiation-induced damaged sides of both the telomere-immortalized human mesenchymal stem cells (hMSCs) and hMSC-telomere 1 (hMSC-telo1) and in control primary hMSCs. Phosphorylated H2AX and WRN immune staining enabled evaluation of overall genomic integrity
and damage/repair. We used peptide nucleic acid−fluorescent in situ hybridization to visualize telomeric damage as a short-term effect. A high-level WRN signal was observed in both primary hMSCs and telomerase-immortalized hMSCs after the cells had been subjected to infrared radiation. Afterward, the irradiation level of the WRN signals decreased considerably, especially in later passages, and WRN was nondetectable in the latest passages of the hMSC Telo1 cells. Contrary to this finding, we found that levels of H2AX phosphorylation in hMSC-telo1 cells increased with time, especially at telomere sides, suggesting that cells with long telomeres and high telomerase activity have the advantage of maintaining genomic integrity. Evaluation of localization of WRN signals demonstrated that WRN does not leave the nucleolus after irradiation. We did not detect the WRN signal at the telomere sides, but we could detect H2AX at the telomeric sides. Thus, our overall data suggest that the WRN protein is not involved in irradiationinduced DNA damage/repair, even at telomeric sides in hMSC and hMSC-telo1.

PB Begell House
LK https://www.dl.begellhouse.com/journals/6dbf508d3b17c437,7963fdcd2773abac,09e3973962e8528c.html