Oxidative stress-induced DNA damage of mouse zygotes triggers G2/M checkpoint and phosphorylates Cdc25 and Cdc2.
In vitro fertilized (IVF) embryos show both cell cycle and developmental arrest. We previously showed oxidative damage activates the ATM → Chk1 → Cdc25B/Cdc25C cascade to mediate G2/M cell cycle arrest for repair of hydrogen peroxide (H2O2)-induced oxidative damage in sperm. However, the mechanisms underlying the developmental delay of zygotes are unknown. To develop a model of oxidative-damaged zygotes, we treated mouse zygotes with different concentrations of H2O2 (0, 0.01, 0.02, 0.03, 0.04, 0.05 mM), and evaluated in vitro zygote development, BrdU incorporation to detect the duration of S phase. We also examined reactive oxygen species level and used immunofluorescence to detect activation of γH2AX, Cdc2, and Cdc25. Oxidatively damaged zygotes showed a delay in G2/M phase and produced a higher level of ROS. At the same time, γH2AX was detected in oxidatively damaged zygotes as well as phospho-Cdc25B (Ser323), phospho-Cdc25C (Ser216), and phospho-Cdc2 (Tyr15). Our study indicates that oxidative stress-induced DNA damage of mouse zygotes triggers the cell cycle checkpoint, which results in G2/M cell cycle arrest, and that phospho-Cdc25B (Ser323), phospho-Cdc25C (Ser216), and phospho-Cdc2 (Tyr15) participate in activating the G2/M checkpoint.
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Yuting
Y
Zhang
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Diting
D
Qian
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China. stlizhiling@126.com.
Zhiling
Z
Li
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Yue
Y
Huang
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Que
Q
Wu
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Gaizhen
G
Ru
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Man
M
Chen
Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou University, Shantou, Guangdong, People's Republic of China.
Bin
B
Wang
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D004249:DNA Damage; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000633:toxicity; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects; D051379:Mice; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D020033:Protein Isoforms / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D013997:Time Factors; D015053:Zygote / Q000201:enzymology* / Q000473:pathology*; D020687:cdc25 Phosphatases / Q000378:metabolism*
D006657:Histones; D020033:Protein Isoforms; C475961:gamma-H2AX protein, mouse; D006861:Hydrogen Peroxide; D016203:CDC2 Protein Kinase; D020687:cdc25 Phosphatases; D001973:Bromodeoxyuridine
Cdc2; Cdc25; DNA damage; G2/M checkpoint; Oxidative stress; Zygote