The thirteen nuclear cleavages that give rise to the Drosophila blastoderm are some of the fastest known cell cycles [1]. Surprisingly, the fertilized egg is provided with at most one-third of the dNTPs needed to complete the thirteen rounds of DNA replication [2]. The rest must be synthesized by the embryo, concurrent with cleavage divisions. What is the reason for the limited supply of DNA building blocks? We propose that frugal control of dNTP synthesis contributes to the well-characterized deceleration of the cleavage cycles and is needed for robust accumulation of zygotic gene products. In support of this model, we demonstrate that when the levels of dNTPs are abnormally high, nuclear cleavages fail to sufficiently decelerate, the levels of zygotic transcription are dramatically reduced, and the embryo catastrophically fails early in gastrulation. Our work reveals a direct connection between metabolism, the cell cycle, and zygotic transcription.
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http://dx.doi.org/10.1016/j.cub.2019.02.028 | DOI Listing |
Ecotoxicol Environ Saf
January 2025
Key Laboratory of Animal Embryo Engineering and Molecular Breeding of Hubei Province, Institute of Animal Sciences and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China. Electronic address:
3-methyl-4-nitrophenol (PNMC), a chemical prevalent in various industries for drug, dye, and leather production, also serves as a primary byproduct of organophosphate insecticides. Despite its global recognition as an endocrine disruptor with documented reproductive toxicity, its detrimental impact on preimplantation embryonic development has yet to be thoroughly investigated. In this study, through the in vitro culture of mice embryos, it was initially observed that even low concentrations of PNMC exposure led to a significant reduction in blastocyst formation and a sharp decline in the ratio of inner cell mass within the blastocysts.
View Article and Find Full Text PDFAnimals (Basel)
December 2024
College of Animal Science and Technology, Shihezi University, Shihezi 832000, China.
Early embryonic development relies on intricately regulated gene expression, and miRNAs influence zygotic genome activation (ZGA), cleavage, and cell fate determination through post-transcriptional regulatory mechanisms. miR-192 is expressed in early pig embryos and participates in various reproductive processes. However, its role in pre-implantation pig embryo development remains poorly understood.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
State Key Laboratory of Wheat Improvement, College of Life Science, Shandong Agricultural University, Tai'an 271018, China.
In many plants, the asymmetric division of the zygote sets up the apical-basal body axis. In the cress , the zygote coexpresses regulators of the apical and basal embryo lineages, the transcription factors WOX2 and WRKY2/WOX8, respectively. WRKY2/WOX8 activity promotes nuclear migration, cellular polarity, and mitotic asymmetry of the zygote, which are hallmarks of axis formation in many plant species.
View Article and Find Full Text PDFDevelopment
January 2025
Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
Emerging evidence suggests that the nuclear pore complex can have unique compositions and distinct nucleoporin functions in different cells. Here, we show that Nup107, a key component of the NPC scaffold, varies in expression over development: it is expressed at higher levels in the blastula compared to the gastrula suggesting a critical role prior to gastrulation. We find depletion of Nup107 affects the differentiation of the early germ layers leading to an expansion of the ectoderm at the expense of endoderm and mesoderm.
View Article and Find Full Text PDFDevelopment
January 2025
Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
Upon fertilization, male and female nuclei fuse to form the zygotic nucleus in angiosperms. Karyogamy is considered to be essential for proper embryogenesis; however, the transcriptional dynamics during karyogamy in plant zygotes remain unclear. In this study, we performed a single-cell transcriptome analysis of rice zygotes at six early developmental stages (15 min, 30 min, 1 h, 2 h, 4 h, and 6 h after gamete fusion) to reveal gene expression profiles during karyogamy in plant zygotes.
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