Core Viewpoint - The research focuses on developing a novel totipotent-like cell-based embryo model that can continuously replicate mouse embryogenesis from zygotic genome activation to gastrulation, providing a powerful platform for studying early mammalian embryonic development [4][12]. Group 1: Research Background - The team from Peking University has been dedicated to the study of chemical small molecules regulating early stem cell developmental potential, establishing extended pluripotent stem cells (EPS cells) in 2017 and totipotent potential stem cells (TPS cells) in 2022, which exhibit significant application potential in constructing embryo models [3][5]. - Current models primarily focus on specific developmental stages, highlighting the need for a continuous in vitro model that replicates the complete developmental trajectory of mouse embryos from pre-implantation to post-implantation [2][3]. Group 2: Methodology and Findings - The research developed a new system for inducing and maintaining mouse totipotent stem cells, successfully constructing an embryo model that simulates mouse embryonic development from E1.5 to E7.5, showing early organogenesis signs [5][12]. - A novel small molecule combination was identified to efficiently induce EPS cells to establish a totipotent network within 48 hours, significantly enhancing cell proliferation rates to match early embryonic cleavage cycles [7][8]. - The model successfully replicated key developmental events, including zygotic genome activation, lineage specification, blastocyst formation, and the establishment of embryonic axes, validated through immunofluorescence and single-cell transcriptomic analysis [8][10]. Group 3: Implications and Future Directions - The model demonstrated the ability to respond to developmental perturbations similarly to natural embryos, indicating its potential for exploring regulatory mechanisms of early embryonic development [10][12]. - Notably, some E7.5-like structures could further develop into morphologically similar E8.5 embryos, showcasing early organogenesis features, thus advancing the understanding of early life formation [12]. - This research not only establishes an efficient method for inducing mouse totipotent stem cells but also provides a new platform for in-depth studies of early embryonic development, moving closer to the ultimate goal of constructing complete living organisms using early stem cells [12].

Core Viewpoint - The research presents a novel method for constructing embryonic models using chemically induced embryonic founder cells (EFC), which allows for a more efficient and accurate simulation of mouse embryogenesis and organogenesis [2][3][6]. Group 1: Research Methodology - The study utilized small molecules (CHIR-99021, E-616452, Lif, AM580) to induce mouse embryonic stem cells into 8-16 cell stage embryonic founder cells (EFC) [6]. - EFC cells can determine all lineages of blastocysts both in vivo and in vitro, enabling the construction of a complete embryonic model [6][9]. - The model accurately replicates the developmental process starting from organ formation, including the formation of three germ layers and early organ structures [6][9]. Group 2: Research Highlights - The system using EFCs allows for direct, rapid, efficient, and accurate construction of in vitro embryonic development models [8]. - Induced EFCs (iEFC) can generate a scalable and faithful embryonic model (iEFC-EM) that reproduces mouse embryonic development up to the organ formation stage [9]. - The model demonstrates the transformation of epithelial cells to mesenchymal cells during gastrulation, leading to the development of various early organ precursors and structures [6][9].