TY - JOUR T1 - Poly(A) tail length is a major regulator of maternal gene expression during the mammalian oocyte-to-embryo transition JF - bioRxiv DO - 10.1101/2021.08.29.458052 SP - 2021.08.29.458052 AU - Yusheng Liu AU - Hu Nie AU - Chuanxin Zhang AU - Zhenzhen Hou AU - Jiaqiang Wang AU - Falong Lu Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/08/31/2021.08.29.458052.abstract N2 - Transcription is silent during the mammalian oocyte-to-embryo transition (OET) until zygotic genome activation (ZGA). Therefore, the OET relies on post-transcriptional regulation of maternal mRNA, among which poly(A) tail lengths have been found to regulate translation for a small number of genes1–3. However, transcriptome-wide poly(A) tail length dynamics and their role in gene expression during the mammalian OET remain unknown. Here, we quantified transcriptome-wide mRNA poly(A) tail length dynamics during the mammalian OET using PAIso-seq1 and PAIso-seq24,5, two methods with different underlying principles that preserve the poly(A) tail information. We revealed that poly(A) tail length was highly dynamic during the mouse OET, and Btg4 is responsible for global maternal mRNA deadenylation. We found that the poly(A) tail length positively associated with translational efficiency transcriptome-wide in mouse oocytes. In addition, genes with different alternative polyadenylation isoforms show longer poly(A) tails for isoforms with distal polyadenylation sites compared to those with proximal polyadenylation sites in mouse, rat, pig and human oocytes after meiotic resumption, which is not seen in cultured cell lines. Surprisingly, mammalian embryos, namely mouse, rat, pig, and human embryos, all experience highly conserved global mRNA re-polyadenylation after fertilization, providing molecular evidence that the early embryo development before ZGA is driven by re-polyadenylated maternal mRNAs rather than newly transcribed mRNAs. Together, our study reveals the conserved mRNA poly(A) tail length landscape. This resource can be used for exploring spatiotemporal post-transcriptional regulation throughout the mammalian OET.Competing Interest StatementThe authors have declared no competing interest. ER -