Spatiotemporal regulation of maternal mRNAs during vertebrate oocyte meiotic maturation

Abstract

Vertebrate oocytes face a particular challenge concerning the regulation of gene expression during meiotic maturation. Global transcription becomes quiescent in fully grown oocytes, remains halted throughout maturation and fertilization, and only resumes upon embryonic genome activation. Hence, the oocyte meiotic maturation process is largely regulated by protein synthesis from pre‐existing maternal messenger RNAs (mRNAs) that are transcribed and stored during oocyte growth. Rapidly developing genome‐wide techniques have greatly expanded our insights into the global translation changes and possible regulatory mechanisms during oocyte maturation. The storage, translation, and processing of maternal mRNAs are thought to be regulated by factors interacting with elements in the mRNA molecules. Additionally, posttranscriptional modifications of mRNAs, such as methylation and uridylation, have recently been demonstrated to play crucial roles in maternal mRNA destabilization. However, a comprehensive understanding of the machineries that regulate maternal mRNA fate during oocyte maturation is still lacking. In particular, how the transcripts of important cell cycle components are stabilized, recruited at the appropriate time for translation, and eliminated to modulate oocyte meiotic progression remains unclear. A better understanding of these mechanisms will provide invaluable insights for the preconditions of developmental competence acquisition, with important implications for the treatment of infertility. This review discusses how the storage, localization, translation, and processing of oocyte mRNAs are regulated, and how these contribute to oocyte maturation progression.

Astrocyte-Derived Exosomes Regulate Sperm miR-34c Levels to Mediate the Transgenerational Effects of Paternal Chronic Social Instability Stress

“…Others have speculated that the increased levels of miRNAs they detect in sperm from stressed mice can nonetheless impact zygotes significantly by excessively suppressing maternal mRNAs. This is because while the maternal versions of these miRNAs are present in oocytes, they are inactive until the 2-cell stage when their endogenous counterparts begin being expressed 35 . However, changes in maternal mRNAs in zygotes from stressed mice have yet to be documented to play a role in the process.…”

Applications of advances in mRNA-based platforms as therapeutics and diagnostics in reproductive technologies

“…Finally, another major player, Nanog, is highly expressed and localized to epiblast, deficiencies in which underlie a failure in appropriate implantation. Importantly, Nanog interacts with numerous other factors (such as CDX2, a Mediator Complex Protein-MED, and Oct4) to regulate status of various RNA transcripts and overall embryonic health (Wu and Schöler, 2014;Cui et al, 2019) (more factors exhaustively reviewed by (Jiang et al, 2023). All such factors underlying these essential events could represent therapeutic targets for embryos, targeting as appropriate to regulates key events during embryogenesis to perhaps enhance chances of successful pregnancy within the clinic.…”

Functions and mechanism of noncoding RNA in regulation and differentiation of male mammalian reproduction

“…64 A subset of testis-specific miRNAs, including Dicer and the mRNA cap-binding protein eIF4E, are associated with MIWI in addition to piRNAs, mRNAs in free RNPs, and polysomes. 65 The epidermis of limb wounds may also produce PIWI proteins, which are necessary for tissue regeneration. 66 This may be because those proteins cause a germline-like condition.…”

“…It is interesting to note that estrogen seems to be able to suppress the expression of the MILI and MIWI genes in the mouse testes, albeit this trait may return on its own after a few days 64 . A subset of testis‐specific miRNAs, including Dicer and the mRNA cap‐binding protein eIF4E, are associated with MIWI in addition to piRNAs, mRNAs in free RNPs, and polysomes 65 …”