Generation and replication-dependent dilution of 5fC and 5caC during mouse preimplantation development

• Published in: Cell research Vol. 21; no. 12; pp. 1670 - 1676
• Main Authors: Inoue, Azusa, Shen, Li, Dai, Qing, He, Chuan, Zhang, Yi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2011; Nature Publishing Group
• Subjects: 5-Methylcytosine - metabolism; 631/337/176/1988; 631/443/494; Animals; Antibodies - immunology; Biomedical and Life Sciences; Cell Biology; Cytosine - analogs & derivatives; Cytosine - immunology; Cytosine - metabolism; Deoxyribonucleic acid; DNA; DNA Replication; DNA-Directed DNA Polymerase - metabolism; Embryonic Development; Immunohistochemistry; Life Sciences; Male; Mice; Original; original-article; Proteins; 一步氧化; 催化转换; 复制; 小鼠; 稀释; 胚胎植入; 胸腺嘧啶; demethylation; 5caC; 5fC; preimplantation
• ISSN: 1001-0602; 1748-7838
• DOI: 10.1038/cr.2011.189

One of the recent advances in the epigenetic field of catalyzing conversion of 5-methylcytosine （5mC） is the demonstration that the Tet family of proteins are capable of DNA to 5-hydroxymethylcytosine （5hmC）. Interestingly, re- cent studies have shown that 5hmC can be further oxidized by Tet proteins to generate 5-formylcytosine （5fC） and 5-carboxylcytosine （5caC）, which can be removed by thymine DNA glycosylase （TDG）. To determine whether Tet- catalyzed conversion of 5mC to 5fC and 5caC occurs in vivo in zygotes, we generated antibodies specific for 5fC and 5caC. By immunostaining, we demonstrate that loss of 5mC in the paternal pronucleus is concurrent with the appearance of 5fC and 5caC, similar to that of 5hmC. Importantly, instead of being quickly removed through an enzyme-catalyzed process, both 5fC and 5caC exhibit replication-dependent dilution during mouse preimplantation development. These results not only demonstrate the conversion of 5mC to 5fC and 5caC in zygotes, but also indicate that both 5fC and 5caC are relatively stable and may be functional during preimplantation development. Together with previous studies, our study suggests that Tet-catalyzed conversion of 5mC to 5hmC/5fC/5caC followed by repli- cation-dependent dilution accounts for paternal DNA demethylation during preimplantation development.