Eif4e1b, a germline-specific paralog of the eukaryotic translation initiation factor 4E family, plays a crucial role in the translation of maternal mRNAs during oogenesis and early embryogenesis [2,3]. It is involved in the oocyte-to-embryo transition (OET) and zygotic genome activation, and is essential for maintaining the dormancy of maternal mRNAs [2,3].

In gene-edited mice, maternal deletion of Eif4e1b leads to multiple defects in oogenesis and embryonic developmental competence during OET [1]. Eif4e1b-cKO oocytes insufficiently synthesize proteins crucial for oocyte maturation and embryonic development, indicating its importance in selective translation activation [1]. In zebrafish, loss of Eif4e1b results in reduced histone mRNA levels in early gonads, suggesting its role in mRNA storage [2]. In mouse oocytes, knockdown of eIF4E1b in GV-stage oocytes and zygotes significantly reduces the rates of oocyte maturation and blastocyst formation, respectively [4].

In conclusion, Eif4e1b is indispensable for the selective translation activation of maternal mRNAs in mammalian oocytes. Studies using Eif4e1b KO/CKO mouse models have provided insights into its role in oogenesis, embryonic development, and the maternal-to-zygotic transition, potentially contributing to understanding related reproductive disorders.