The translational landscape of mouse oocytes and preimplantation embryos revealed by high-resolution ribosome profiling

Translational regulation plays a critical role during oocyte and preimplantation embryo development. Here, we utilized high resolution ribosome fractionation and low-input ribosome profiling of mouse oocytes and preimplantation embryos to explore the translational landscapes of early embryo development. The inconsistency was observed when comparing polysome-bound, monosome-bound, and free RNA profiles, indicating the role of ribosomes in manipulating RNA fate, especially for oocyte-to-embryo transition (OET) and zygotic genome activation (ZGA). Moreover, eif1ad3 with its homologs, including eif1ad4, eif1ad6, eif1ad7, etc. are highly translated during ZGA and regulating the translational activity of other genes. Knocking down these genes lead to defective ZGA and preimplantation development. These data reveal that the transcriptome and translatome manipulate RNA fate collectively to regulate mouse preimplantation development. Ten equal fractions of ribosome fractionation were recovered from 100 oocytes (GV or MII oocyte) or embryos at different developmental stages (zygote, 2-, 4-, 8-cell, morula, and blastocyst) and subjected to RNA isolation, followed by RNA-sequencing analysis. Also, a pool of 20 oocytes or preimplantation embryos (n=4) selected from the same batch in each developmental stage used for ribosome profiling were used to profile transcriptomes by RNA-seq following Smart-seq2 protocol.