Previous work from our laboratory has demonstrated that specific rabbit immunoglobulins G (IgG) against a glycoprotein antigen of rat kidney proximal tubule or a cross-reacting visceral yolk-sac endodermal cell antigen will induce abnormal embryonic development when they are injected into pregnant rats during the period of organogenesis. It has been proposed that these antibodies may induce embryopathy by interfering with functions of the visceral yolk-sac placenta, an important organ providing nutrients to the embryo at this stage of development. In order to gain some insight into the underlying pathogenic mechanism(s) in which specific teratogenic IgG may interfere with visceral yolk-sac functions, we examined the uptake of these teratogenic IgG by the visceral yolk-sac endodermal cells at the electron microscopic level. The results demonstrated that teratogenic rabbit IgG specifically localized on the fuzzy coat of the external apical cell membrane of the visceral yolk-sac endoderm at the intermicrovillous region. Within 5 min, the IgG were rapidly internalized via coated pits and micropinocytic vesicles. Within 30 min, an increasing proportion of gold particles appeared within uncoated vesicles or vacuoles of various sizes; most of the gold particles were in close proximity to the inner membranous lining of the vesicles. Similar findings were observed after 1- or 2-hr incubation. After 24- to 48-hr culture, however, the gold particles appeared to have dissociated from the inner surface of the vesicle membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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http://dx.doi.org/10.1002/aja.1001830203 | DOI Listing |
Dev Biol
January 2025
Developmental Biology & Cancer Department, UCL Great Ormond Street Institute of Child Health, London, UK.
Reichert's membrane (RM) is a basement membrane of gigantic proportions that surrounds the mammalian embryo following implantation. It is part of the parietal yolk sac, which originates from the wall of the preimplantation blastocyst. RM persists from implantation to birth in rodents and analogous structures occur in other mammals, including primates.
View Article and Find Full Text PDFNat Cell Biol
January 2025
Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China.
Gastrulation marks a pivotal stage in mammalian embryonic development, establishing the three germ layers and body axis through lineage diversification and morphogenetic movements. However, studying human gastrulating embryos is challenging due to limited access to early tissues. Here we show the use of spatial transcriptomics to analyse a fully intact Carnegie stage 7 human embryo at single-cell resolution, along with immunofluorescence validations in a second embryo.
View Article and Find Full Text PDFFEBS Lett
November 2024
Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan.
Iqsec1 (IQ motif and Sec7 domain-containing protein 1), also known as BRAG2 (Brefeldin A-resistant Arf-GEF 2), is a guanine nucleotide exchange factor that regulates membrane trafficking, cytoskeletal organization, and signal transduction by activating class II and III ADP-ribosylation factors. To investigate the physiological role of Iqsec1 at the whole animal level, we generated Iqsec1-deficient mice using CRISPR/Cas9-mediated gene editing. Nearly all Iqsec1 mice (99%) exhibited embryonic lethality with severe growth retardation.
View Article and Find Full Text PDFElife
October 2024
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
Sci Rep
June 2024
Faculty of Medicine, University Hospital of Cologne, Institute of Pathology, University of Cologne, Cologne, Germany.
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