Translational regulation plays a pivotal role during pre-implantation development. However, the mechanisms by which messenger RNAs (mRNAs) are selectively regulated over time, along with their dynamic utilization and fate during this period, remain largely unknown. Here, we performed fraction-resolved polysome profiling and characterized translational dynamics across oocytes and early embryo development. This approach allowed us to examine the changes in translation during pre-implantation development in high resolution and uncover previously unrecognized modes of translational selectivity. We observed a stage-specific delay in translation, characterized by the postponed recruitment of stored mRNAs-either unbound or associated with light ribosomal fractions-into actively translating polysomes (heavy fraction). Comparative analysis of translatome with proteomics, RNA N6-methyladenosine modifications, and mRNA features further revealed both coordinated and distinct regulatory mechanisms during pre-implantation development. Furthermore, we identified a eukaryotic initiation factor 1A domain containing 3, Eif1ad3, which is exclusively translated at the two-cell stage and is essential for embryonic development by regulating ribosome biogenesis and protein synthesis. Collectively, our study provides a valuable resource of spatiotemporal translational regulation in mammalian pre-implantation development and highlights a previously uncharacterized translation initiation factor critical for early embryos.

• MeSH
• adenosin analogy a deriváty   metabolismus   MeSH
• blastocysta metabolismus   MeSH
• embryonální vývoj * genetika   MeSH
• eukaryotický iniciační faktor 1 metabolismus   genetika   MeSH
• messenger RNA * metabolismus   genetika   MeSH
• myši MeSH
• oocyty metabolismus   růst a vývoj   MeSH
• polyribozomy metabolismus   genetika   MeSH
• proteosyntéza * MeSH
• ribozomy metabolismus   MeSH
• vývojová regulace genové exprese * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adenosin MeSH
• eukaryotický iniciační faktor 1 MeSH
• messenger RNA * MeSH
• N-methyladenosine MeSH Prohlížeč

Transcriptional activity and gene expression are critical for the development of mature, meiotically competent oocytes. Our study demonstrates that the absence of cyclin-dependent kinase 12 (CDK12) in oocytes leads to complete female sterility, as fully developed oocytes capable of completing meiosis I are absent from the ovaries. Mechanistically, CDK12 regulates RNA polymerase II activity in growing oocytes and ensures the maintenance of the physiological maternal transcriptome, which is essential for protein synthesis that drives further oocyte growth. Notably, CDK12-deficient growing oocytes exhibit a 71% reduction in transcriptional activity. Furthermore, impaired oocyte development disrupts folliculogenesis, leading to premature ovarian failure without terminal follicle maturation or ovulation. In conclusion, our findings identify CDK12 as a key master regulator of the oocyte transcriptional program and gene expression, indispensable for oocyte growth and female fertility. A schematic illustrating the effects of loss of CDK12 in mammalian oocytes on the regulation of transcription by polymerase II and the concomitant effects on translation. This disruption leads to an aberrant transcriptome and translatome, resulting in the absence of fully mature oocytes and ultimately female sterility.

• MeSH
• cyklin-dependentní kinasy * metabolismus   nedostatek   genetika   MeSH
• lidé MeSH
• meióza genetika   MeSH
• myši MeSH
• oocyty * metabolismus   enzymologie   patologie   MeSH
• oogeneze MeSH
• ovariální folikul metabolismus   MeSH
• primární ovariální insuficience genetika   patologie   MeSH
• RNA-polymerasa II metabolismus   MeSH
• transkriptom MeSH
• ženská infertilita * genetika   patologie   enzymologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklin-dependentní kinasy * MeSH
• RNA-polymerasa II MeSH

High-resolution ribosome fractionation and low-input ribosome profiling of bovine oocytes and preimplantation embryos has enabled us to define the translational landscapes of early embryo development at an unprecedented level. We analyzed the transcriptome and the polysome- and non-polysome-bound RNA profiles of bovine oocytes (germinal vesicle and metaphase II stages) and early embryos at the two-cell, eight-cell, morula and blastocyst stages, and revealed four modes of translational selectivity: (1) selective translation of non-abundant mRNAs; (2) active, but modest translation of a selection of highly expressed mRNAs; (3) translationally suppressed abundant to moderately abundant mRNAs; and (4) mRNAs associated specifically with monosomes. A strong translational selection of low-abundance transcripts involved in metabolic pathways and lysosomes was found throughout bovine embryonic development. Notably, genes involved in mitochondrial function were prioritized for translation. We found that translation largely reflected transcription in oocytes and two-cell embryos, but observed a marked shift in the translational control in eight-cell embryos that was associated with the main phase of embryonic genome activation. Subsequently, transcription and translation become more synchronized in morulae and blastocysts. Taken together, these data reveal a unique spatiotemporal translational regulation that accompanies bovine preimplantation development.

• Klíčová slova
• Bovine, Preimplantation embryo development, Ribosome profiling, Transcription, Translation, Translational selectivity,
• MeSH
• blastocysta * metabolismus   MeSH
• embryonální vývoj * genetika   MeSH
• morula metabolismus   MeSH
• oocyty metabolismus   MeSH
• ribozomy genetika   MeSH
• skot MeSH
• těhotenství MeSH
• vývojová regulace genové exprese MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH