RNA m6A methylome in mouse oocytes and preimplantation embryos

N6-methyladenosine (m6A), the most prevalent internal modification in eukaryotic messenger RNA, plays diverse regulatory roles in many biological processes and is involved in a variety of physiological behaviors. Here we present the m6A methylome maps of mouse oocytes and preimplantation embryos by a low-input approach picoMeRIP-seq. We revealed that m6A was largely and dynamically deposited on maternal and zygotic RNAs during maternal-to-zygotic transition (MZT), especially on those encoding the factors essential for cell fate determination. m6A frequently marked the maternally-derived RNAs to be degraded and the genes that were activated during zygotic genome activation. Moreover, the RNAs derived from retrotransposons, such as MTA and MERVL, were heavily occupied by m6A. Collectively, our results provide a foundation for future studies exploring the regulatory roles of m6A in mammalian early embryo development. Using picoMeRIP-seq we developed, the transcriptome-wide m6A maps were generated at six developmental stages including oocytes at germinal vesicle (GV) and metaphase II (MII) stages, and embryos at zygote, 2-cell, 8-cell and blastocyst stages, with two biological replicates for each stage.