The extra-embryonic yolk sac (YS) is the first hematopoietic site in the mouse embryo and is thought to generate only primitive erythroid and myeloerythroid progenitor cells before definitive HSC emergence within the embryo on E10.5. Here, we have shown the existence of T cell-restricted progenitors in the E9.5 YS that directly engraft in recipient immunodeficient mice. T-cell progenitors were also produced in vitro from both YS and para-aortic splanchnopleura hemogenic endothelial cells, and these T-cell progenitors repopulated the thymus and differentiated into mature T-cell subsets in vivo on transplantation. Our data confirm that the YS produces T-lineage-restricted progenitors that are available to colonize the thymus and provide new insight into the YS as a definitive hematopoietic site in the mouse embryo.
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http://dx.doi.org/10.1182/blood-2011-12-397489 | DOI Listing |
Gene
March 2025
Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan; Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan. Electronic address:
Bird contour feathers exhibit a complex hierarchical structure composed of a rachis, barbs, and barbules, with barbules playing a crucial role in maintaining feather structure and function. Understanding the molecular mechanisms underlying barbule formation is essential for advancing our knowledge of avian biology and evolution. In this study, we identified a novel gene, pennaceous barbule cell factor (PBCF), using microarray analysis, RT-PCR, and in situ hybridization.
View Article and Find Full Text PDFLife Sci Alliance
March 2025
https://ror.org/05f950310 Department of Development and Regeneration, Stem Cell Institute, KU Leuven, Leuven, Belgium
Mammalian pre-implantation development is entirely devoted to the specification of extra-embryonic lineages, which are fundamental for embryo morphogenesis and support. The second fate decision is taken just before implantation, as defined by the epiblast (EPI) and the primitive endoderm (PE) specification. Later, EPI forms the embryo proper and PE contributes to the formation of the yolk sac.
View Article and Find Full Text PDFAnimal
December 2024
Department of Animal Breeding and Nutrition, Faculty of Animal Breeding and Biology, Bydgoszcz University of Science and Technology, 85-084 Bydgoszcz, Poland.
Storage duration affects the biological value of hatching eggs. The study evaluated the composition and characteristics of hatching eggs from Rosa 1 hens, the morphometric traits of embryos and chicks, and hatching results based on storage time. A total of 1 200 hatching eggs were divided into three groups: NS (control, non-stored), S4 (stored up to day 4), and S7 (stored up to day 7).
View Article and Find Full Text PDFThe yolk sac is phylogenetically the oldest of the extra-embryonic membranes and plays important roles in nutrient transfer during early pregnancy in many species. In the human this function is considered largely vestigial, in part because the secondary yolk sac never makes contact with the inner surface of the chorionic sac. Instead, it is separated from the chorion by the fluid-filled extra-embryonic coelom and attached to the developing embryo by a relatively long vitelline duct.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA; Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA. Electronic address:
In zebrafish, maternally deposited yolk is the source of nutrients for embryogenesis prior to digestive system maturation. Yolk nutrients are processed and secreted to the growing organism by an extra-embryonic tissue, the yolk syncytial layer (YSL). The export of lipids from the YSL occurs through the production of triacylglycerol-rich lipoproteins.
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