Investigating the role of WRN and BLM in BMVC4-induced DNA damage response and senescence

• Main Authors: Chen-Yeh Yu, 余承曄
• Other Authors: Jing-Jer Lin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/85041273154578213023

碩士 === 國立臺灣大學 === 生物化學暨分子生物學研究所 === 103 === G-quadruplex is a non-canonical B form DNA structure, it plays an important role in the sense of physiology. For example, G-quadruplex participates in the regulation of telomere, DNA replication and transcriptional regulation. BMVC4 is a novel G-quadruplex stabilizer. It was synthesized through the collaboration with Dr. Chang, Academic Sinica. We found that BMVC4 could not only inhibit telomerase activity in H1299, non-small cell lung cancer, but also shorten telomere length, eventually lead to cellular senescence. BMVC4 also caused DNA damage response and DNA strand breaks. After the measurement of immunofluorescence, we found only 20% DNA damage response that arose from telomere. Therefore, the occurrence of DNA damage response maybe come from the other site of the chromosomes. WRN and BLM belong to RecQ helicase family. It is well established that WRN and BLM have capability in preferentially binding to G-quadruplex, replication fork and holliday junction structure. Both of them have high efficiency in resolving these special structures. They play a vital role in DNA repair, DNA replication and telomere maintenance. Because WRN and BLM could resolving G-quadruplex structure, we test if there is a correlation between WRN or BLM and the stabilization of G-quadruplex by BMVC4. We knocked down the expression of WRN and BLM respectively and found that the expression of pATM and total ATM was in concert with the expression of WRN or BLM. It is possible that WRN or BLM may function as the upstream signal of DNA damage response, which caused by the effect of BMVC4. That is, WRN or BLM might be required for eliciting the DNA damage response. We also found that WRN or BLM depletion caused H1299 cells to stop proliferating after a short period, no matter the treatment of BMVC4 or not. In addition, through SA-β-gal analysis, we found that the depletion of WRN or BLM induced cellular senescent phenotype. In conclusion, WRN and BLM are not simply the pivotal regulator of DNA damage response caused by BMVC4, but likewise have deeply influence in cell growth and cellular senescence.