1. Roles of the first and second round of DNA replication in the regulation of zygotic gene activation in mice.
- Author
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Sonehara H, Nagata M, and Aoki F
- Subjects
- Animals, Aphidicolin pharmacology, Cleavage Stage, Ovum drug effects, Cleavage Stage, Ovum physiology, DNA Replication drug effects, Embryonic Development drug effects, Embryonic Development genetics, Eukaryotic Initiation Factor-1 genetics, Eukaryotic Initiation Factor-1 metabolism, Female, Gene Expression Regulation, Developmental drug effects, Genes, Developmental drug effects, Genes, Developmental physiology, HSP70 Heat-Shock Proteins genetics, HSP70 Heat-Shock Proteins metabolism, Kruppel-Like Transcription Factors genetics, Kruppel-Like Transcription Factors metabolism, Male, Mice, Nucleic Acid Synthesis Inhibitors, Pregnancy, Proteins genetics, Proteins metabolism, Transcription Factors genetics, Transcription Factors metabolism, Zygote drug effects, DNA Replication physiology, Gene Expression Regulation, Developmental physiology, Zygote metabolism
- Abstract
In the mouse embryo, expression of zygotic genes starts in the S/G2 phase of the 1-cell stage and greatly increases during the 2-cell stage. Although the timing of zygotic gene activation (ZGA) is thus established, the mechanism regulating ZGA is poorly understood. Previous studies using reporter genes have suggested that a transcriptionally repressive state is established during the 2-cell stage and that the first and second rounds of DNA replication are involved in this process. To further elucidate the respective roles of the two rounds of DNA replication in ZGA, we analyzed the expression of four ZGA genes (hsp70.1, eif-1a, muerv and zscan4d) in embryos whose DNA replication was inhibited by treatment with aphidicolin, an inhibitor of DNA polymerase. Inhibiting the first round increased the expression levels of hsp70.1, eif-1a and zscan4d but decreased that of muerv, while inhibiting the second round increased the expression levels of all four genes. These results suggest that the transcriptionally repressive state seems to be established after the second round of DNA replication.
- Published
- 2008
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