1. Activation of the Prereplication Complex Is Blocked by Mimosine through Reactive Oxygen Species-activated Ataxia Telangiectasia Mutated (ATM) Protein without DNA Damage.
- Author
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Shoichi Kubota, Yasunori Fukumoto, Kenichi Ishibashi, Shuhei Soeda, Sho Kubota, Ryuzaburo Yuki, Yuji Nakayama, Kazumasa Aoyama, Noritaka Yamaguchi, and Naoto Yamaguchi
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MIMOSINE , *REACTIVE oxygen species , *ATAXIA telangiectasia mutated protein , *DNA damage , *DNA replication - Abstract
Mimosine is an effective cell synchronization reagent used for arresting cells in late G1 phase. However, the mechanism underlying mimosine-induced G1 cell cycle arrest remains unclear. Using highly synchronous cell populations, we show here that mimosine blocks S phase entry through ATM activation. HeLa S3 cells are exposed to thymidine for 15 h, released for9hb y washing out the thymidine, and subsequently treated with 1mM mimosine for a further 15 h (thymidine → mimosine). In contrast to thymidine-induced S phase arrest, mimosine treatment synchronizes >90% of cells at the G1 -S phase boundary by inhibiting the transition of the prereplication complex to the preinitiation complex. Mimosine treatment activates ataxia telangiectasia mutated (ATM)/ataxia telangiectasia and Rad3-related (ATR)-mediated checkpoint signaling without inducing DNA damage. Inhibition of ATM activity is found to induce mimosine-arrested cells to enter S phase. In addition, ATM activation by mimosine treatment is mediated by reactive oxygen species (ROS). These results suggest that, upon mimosine treatment, ATM blocks S phase entry in response to ROS, which prevents replication fork stalling-induced DNA damage. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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