IN BRIEF: Proper degradation of maternally inherited proteins is a prerequisite for successful embryonic development. This study shows the species-specificity of this process. ABSTRACT: The mechanism of targeting maternal proteins for degradation during preimplantation development is an unexplored process. Only a few proteins that need to be degraded for the proper course of the maternal-to-zygotic transition have been described in mice, and a few more in non-mammalian species. However, it is not well known whether the need for degradation is conserved across species or if it is driven in a species-specific way. Therefore, we selected six proteins that need to be degraded for the proper course of the maternal-to-zygotic transition in mice or Xenopus, and thoroughly characterized their expression at both the mRNA and protein level during bovine embryogenesis. Further, we analysed the protein expression in mice and pigs and compared it to bovine embryos. Thus, we provide a unique interspecies comparison of three mammalian representatives. We found that the degree of conservation between species is low and does not depend on the evolutionary relatedness of the species. This paper suggests that protein degradation during preimplantation development is controlled by a combination of species-specific factors from the embryo and the sequences of protein homologues.

• Keywords
• cattle, embryonic genome activation, maternal protein, preimplantation development, protein degradation,
• MeSH
• Blastocyst * metabolism   MeSH
• Species Specificity MeSH
• Embryonic Development * physiology   MeSH
• Mice MeSH
• Swine MeSH
• Proteolysis * MeSH
• Cattle MeSH
• Gene Expression Regulation, Developmental MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Cattle MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Assisted Reproductive Technologies (ART) have revolutionized infertility treatment and animal breeding, but their success largely depends on selecting high-quality oocytes for fertilization and embryos for transfer. During preimplantation development, embryos undergo complex morphogenetic processes, such as compaction and cavitation, driven by cellular forces dependent on cytoskeletal dynamics and cell-cell interactions. These processes are pivotal in dictating an embryo's capacity to implant and progress to full-term development. Hence, a comprehensive grasp of the biomechanical attributes characterizing healthy oocytes and embryos is essential for selecting those with higher developmental potential. Various noninvasive techniques have emerged as valuable tools for assessing biomechanical properties without disturbing the oocyte or embryo physiological state, including morphokinetics, analysis of cytoplasmic movement velocity, or quantification of cortical tension and elasticity using microaspiration. By shedding light on the cytoskeletal processes involved in chromosome segregation, cytokinesis, cellular trafficking, and cell adhesion, underlying oogenesis, and embryonic development, this review explores the significance of embryo biomechanics in ART and its potential implications for improving clinical IVF outcomes, offering valuable insights and research directions to enhance oocyte and embryo selection procedures.

• Keywords
• assisted reproductive technologies, biomechanics, cytoskeleton, embryo, mouse, oocyte, preimplantation development, quality assessment,
• Publication type
• Journal Article MeSH
• Review MeSH

SCF-dependent proteolysis was first discovered via genetic screening of budding yeast almost 25 years ago. In recent years, more and more functions of SCF (Skp1-Cullin 1-F-box) ligases have been described, and we can expect the number of studies on this topic to increase. SCF ligases, which are E3 ubiquitin multi-protein enzymes, catalyse protein ubiquitination and thus allow protein degradation mediated by the 26S proteasome. They play a crucial role in the degradation of cell cycle regulators, regulation of the DNA repair and centrosome cycle and play an important role in several diseases. SCF ligases seem to be needed during all phases of development, from oocyte formation through fertilization, activation of the embryonic genome to embryo implantation. In this review, we summarize known data on SCF ligase-mediated degradation during oogenesis and embryogenesis. In particular, SCFβTrCP and SCFSEL-10/FBXW7 are among the most important and best researched ligases during early development. SCFβTrCP is crucial for the oogenesis of Xenopus and mouse and also in Xenopus and Drosophila embryogenesis. SCFSEL-10/FBXW7 participates in the degradation of several RNA-binding proteins and thereby affects the regulation of gene expression during the meiosis of C. elegans. Nevertheless, a large number of SCF ligases that are primarily involved in embryogenesis remain to be elucidated.

• Keywords
• SCF ligases, embryogenesis, oogenesis, ubiquitin, ubiquitin-proteasome system,
• MeSH
• Models, Biological MeSH
• Embryonic Development * MeSH
• Oocytes cytology   metabolism   MeSH
• Oogenesis * MeSH
• SKP Cullin F-Box Protein Ligases metabolism   MeSH
• Substrate Specificity MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• SKP Cullin F-Box Protein Ligases MeSH