Release of E2F1/DP1 heterodimers from repression mediated by the retinoblastoma tumor suppressor (pRB) triggers cell cycle entry into S phase, suggesting that E2F1 and DP1 proteins must act in unison, either to facilitate or to suppress cell-cycle progression. In stark contrast to the milder phenotypes that result from inactivation of E2Fs, we report that loss of Dp1 leads to death in utero because of the failure of extra-embryonic development. Loss of Dp1 compromises the trophectoderm-derived tissues - specifically, the expansion of the ectoplacental cone and chorion, and endoreduplication in trophoblast giant cells. Inactivation of p53 is unable to rescue the Dp1-deficient embryonic lethality. Thus, DP1 is absolutely required for extra-embryonic development and consequently embryonic survival, consistent with E2F/DP1 normally acting to promote growth in vivo.
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http://dx.doi.org/10.1242/dev.00355 | DOI Listing |
Biochem Soc Trans
January 2025
Centre for Plant Molecular Biology, University of Tübingen, Tübingen 72076, Germany.
Primary axis formation is the first step of embryonic patterning in flowering plants and recent findings highlight the importance of parent-of-origin effects in this process. Apical-basal patterning has a strong influence on suspensor development, an extra-embryonic organ involved in nutrient transport to the embryo at an early stage of seed development. The endosperm, a second fertilization product, nourishes the embryo at later stages of seed development.
View Article and Find Full Text PDFHum Mol Genet
January 2025
Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park, Earlham Road, Norwich NR4 6PN, United Kingdom.
Genomic imprinting is the parent-of-origin dependent monoallelic expression of genes often associated with regions of germline-derived DNA methylation that are maintained as differentially methylated regions (gDMRs) in somatic tissues. This form of epigenetic regulation is highly conserved in mammals and is thought to have co-evolved with placentation. Tissue-specific gDMRs have been identified in human placenta, suggesting that species-specific imprinting dependent on unorthodox epigenetic establishment or maintenance may be more widespread than previously anticipated.
View Article and Find Full Text PDFDevelopment
January 2025
Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
In chick embryos before primitive streak formation, the outermost extra-embryonic region, known as the area opaca (AO), was generally thought to act only by providing nutrients and mechanical support to the embryo. Immediately internal to the AO is a ring of epiblast called the marginal zone (MZ), separating the former from the inner area pellucida (AP) epiblast. The MZ does not contribute cells to any part of the embryo but is involved in determining the position of primitive streak formation from the adjacent AP epiblast.
View Article and Find Full Text PDFGene
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.
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