Poly(ADP-ribosylation) of atypical CS histone variants is required for the progression of S phase in early embryos of sea urchins

1991 ◽  
Vol 46 (3) ◽  
pp. 234-241 ◽  
Author(s):  
M. Imschenetzky ◽  
M. Montecino ◽  
M. Puchi
Keyword(s):  
Sea Urchins ◽  
Histone Variants ◽  
S Phase ◽  
Adp Ribosylation ◽  
Early Embryos

scholarly journals Poly(ADP-ribosylation) protects maternally derived histones from proteolysis after fertilization

1999 ◽  
Vol 343 (1) ◽  
pp. 95-98 ◽  
Author(s):  
Violeta MORIN ◽  
Freddy DIAZ ◽  
Martin MONTECINO ◽  
Linda FOTHERGILL-GILMORE ◽  
Marcia PUCHI ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Cysteine Proteinase ◽  
Histone Variants ◽  
Nuclear Proteins ◽  
Post Translational Modification ◽  
Cleavage Stage ◽  
Adp Ribosylation ◽  
Ribose Moiety

Fertilization in sea urchins is followed by the replacement of sperm-specific histones by cleavage-stage histone variants recruited from maternal stores. Such remodelling of zygote chromatin involves a cysteine proteinase that degrades the sperm-specific histones in a selective manner, leaving the maternal cleavage-stage histone variants intact. The mechanism that determines the selectivity of the sperm-histone-selective proteinase (SpH-proteinase) was analysed by focusing on the post-translational modification status of both sets of histones. It has previously been reported that only native cleavage-stage histones are poly(ADP-ribosylated), whereas the sperm-specific histones are not modified. To determine whether the poly(ADP-ribose) moiety afforded protection from degradation, the ADP-ribose polymers were removed from the cleavage-stage histones in vitro; these proteins were then assayed as potential substrates of the SpH-proteinase. Strikingly, the cleavage-stage histone variants were extensively degraded after the enzymic removal of their ADP-ribose moieties. In addition, the SpH cysteine proteinase was not inhibited by isolated poly(ADP-ribose) polymers. Consequently, only poly(ADP-ribosylated) cleavage-stage histone variants are protected from proteolysis. These results demonstrate a novel role for this type of post-translational modification, namely the protection of nuclear proteins against nuclear proteinases after fertilization.

Hybrid nucleoprotein particles containing a subset of male and female histone variants form during male pronucleus formation in sea urchins

1996 ◽  
Vol 63 (4) ◽  
pp. 385-394 ◽  
Author(s):  
Maria Imschenetzky ◽  
María Isabel Oliver ◽  
Soraya Gutiérrez ◽  
Violeta Morín ◽  
Cecilia Garrido ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Histone Variants ◽  
Male And Female ◽  
Male Pronucleus

Biogenic Monoamines in Early Embryos of Sea Urchins

1981 ◽  
Vol 4 (4) ◽  
pp. 322-328 ◽  
Author(s):  
B.N. Manukhin ◽  
E.V. Volina ◽  
L.N. Markova ◽  
L. Rakić ◽  
G.A. Buznikov
Keyword(s):  
Sea Urchins ◽  
Biogenic Monoamines ◽  
Early Embryos

scholarly journals Hydrozoan sperm-specific H2B histone variants stabilize chromatin and block transcription without enhancing chromatin condensation

2021 ◽  
Author(s):  
Anna Torok ◽  
Martin JG Browne ◽  
Jordina C Vilar ◽  
Indu Patwal ◽  
Timothy Q DuBuc ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Chromatin Condensation ◽  
Ectopic Expression ◽  
Cell Types ◽  
Histone Variants ◽  
Sperm Chromatin ◽  
Chromatin Compaction ◽  
Cycle Arrest

Many animals achieve sperm chromatin compaction and stabilisation during spermatogenesis by replacing canonical histones with sperm nuclear basic proteins (SNBPs) such as protamines. A number of animals including hydrozoan cnidarians and echinoid sea urchins lack protamines and have instead evolved a distinctive family of sperm-specific histone H2Bs (spH2Bs) with extended N-termini rich in SPKK-related motifs. Sperm packaging in echinoids such as sea urchins is regulated by spH2Bs and their sperm is negatively buoyant for fertilization on the sea floor. Hydroid cnidarians also package sperm with spH2Bs but undertake broadcast spawning and their sperm properties are poorly characterised. We show that sperm chromatin from the hydroid Hydractinia possesses higher stability than its somatic equivalent, with reduced accessibility of sperm chromatin to transposase Tn5 integration in vivo and to endonucleases in vitro. However, nuclear dimensions are only moderately reduced in mature Hydractinia sperm compared to other cell types. Ectopic expression of spH2B in the background of H2B knockdown resulted in downregulation of global transcription and cell cycle arrest in embryos without altering their nuclear density. Taken together, spH2B variants containing SPKK-related motifs act to stabilise chromatin and silence transcription in Hydractinia sperm without significant chromatin compaction. This is consistent with a contribution of spH2B to sperm buoyancy as a reproductive adaptation.

scholarly journals Heterochromatin Morphodynamics in Late Oogenesis and Early Embryogenesis of Mammals

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1497 ◽  
Author(s):  
Irina Bogolyubova ◽  
Dmitry Bogolyubov
Keyword(s):  
Molecular Mechanisms ◽  
Chromatin Condensation ◽  
Mammalian Species ◽  
Biological Significance ◽  
Histone Variants ◽  
Nuclear Bodies ◽  
Mammalian Development ◽  
Oocyte Growth ◽  
Early Embryos ◽  
Early Mammalian Development

During the period of oocyte growth, chromatin undergoes global rearrangements at both morphological and molecular levels. An intriguing feature of oogenesis in some mammalian species is the formation of a heterochromatin ring-shaped structure, called the karyosphere or surrounded “nucleolus”, which is associated with the periphery of the nucleolus-like bodies (NLBs). Morphologically similar heterochromatin structures also form around the nucleolus-precursor bodies (NPBs) in zygotes and persist for several first cleavage divisions in blastomeres. Despite recent progress in our understanding the regulation of gene silencing/expression during early mammalian development, as well as the molecular mechanisms that underlie chromatin condensation and heterochromatin structure, the biological significance of the karyosphere and its counterparts in early embryos is still elusive. We pay attention to both the changes of heterochromatin morphology and to the molecular mechanisms that can affect the configuration and functional activity of chromatin. We briefly discuss how DNA methylation, post-translational histone modifications, alternative histone variants, and some chromatin-associated non-histone proteins may be involved in the formation of peculiar heterochromatin structures intimately associated with NLBs and NPBs, the unique nuclear bodies of oocytes and early embryos.

RNA synthesis in the early embryogenesis of a fish (Misgurnus fossilis)

Development ◽  
1969 ◽  
Vol 21 (2) ◽  
pp. 295-308
Author(s):  
C. A. Kafiani ◽  
M. J. Timofeeva ◽  
A. A. Neyfakh ◽  
N. L. Melnikova ◽  
J. A. Rachkus
Keyword(s):  
Rna Synthesis ◽  
Animal Species ◽  
Sea Urchins ◽  
Early Embryogenesis ◽  
Gastrula Stage ◽  
Cell Nuclei ◽  
Ribonucleic Acids ◽  
Early Embryos ◽  
Apparent Conflict ◽  
Misgurnus Fossilis

Synthesis of ribonucleic acids in early embryos has been extensively studied during recent years in a number of laboratories and has been shown to begin shortly after fertilization (Kafiani, Tatarskaya & Kanopkayte, 1958; Wilt, 1963; Brown & Littna, 1964; Decroly, Cape & Brachet, 1964; Glišin & Glišin, 1964; Kafiani & Timofeeva, 1964, 1965; Nemer & Infant, 1965). Early embryos of Xenopus (Brown & Gurdon, 1964; Brown & Littna, 1964, 1966) and of sea urchins (Wilt, 1963; Glišin & Glišin, 1964; Nemer & Infant, 1965) synthesize up to gastrula stage predominantly or exclusively polydisperse RNA of a nonribosomal nature usually referred to as DNA-like RNA (dRNA). The occurrence of continuous dRNA synthesis in early embryogenesis is in apparent conflict with the periodicity of the 'morphogenetic function' of cell nuclei found by one of us (Neyfakh, 1959, 1961, 1964, 1965) in embryos of a number of animal species.

scholarly journals Visualizing the dynamics of histone variants in the S-phase nucleus

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Stella Maxouri ◽  
Stavros Taraviras ◽  
Zoi Lygerou
Keyword(s):  
Histone Variants ◽  
S Phase ◽  
Phase Nucleus

Electrical coupling of blastomeres in early embryos of ascidians and sea urchins

1982 ◽  
Vol 140 (2) ◽  
pp. 457-461 ◽  
Author(s):  
B DALE ◽  
A DESANTIS ◽  
G ORTOLANI ◽  
M RASOTTO ◽  
L SANTELLA
Keyword(s):  
Sea Urchins ◽  
Electrical Coupling ◽  
Early Embryos

scholarly journals Physical constraints on early blastomere packings

2020 ◽  
Author(s):  
James Giammona ◽  
Otger Campàs
Keyword(s):  
Developmental Stages ◽  
Sea Urchins ◽  
Physical Parameters ◽  
Cell Stage ◽  
Physical Constraints ◽  
C Elegans ◽  
Deformable Particles ◽  
Early Embryos ◽  
Square Configuration ◽  
The Right

AbstractAt very early embryonic stages, when embryos are composed of just a few cells, establishing the correct packing arrangements (contacts) between cells is essential for the proper development of the organism. As early as the 4-cell stage, the observed cellular packings in different species are distinct and, in many cases, differ from the equilibrium packings expected for simple adherent and deformable particles. It is unclear what are the specific roles that different physical parameters, such as the forces between blastomeres, their division times, orientation of cell division and embryonic confinement, play in the control of these packing configurations. Here we simulate the non-equilibrium dynamics of cells in early embryos and systematically study how these different parameters affect embryonic packings at the 4-cell stage. In the absence of embryo confinement, we find that cellular packings are not robust, with multiple packing configurations simultaneously possible and very sensitive to parameter changes. Our results indicate that the geometry of the embryo confinement determines the packing configurations at the 4-cell stage, removing degeneracy in the possible packing configurations and overriding division rules in most cases. Overall, these results indicate that physical confinement of the embryo is essential to robustly specify proper cellular arrangements at very early developmental stages.Author summaryAt the initial stages of embryogenesis, the precise arrangement of cells in the embryo is critical to ensure that each cell gets the right chemical and physical signals to guide the formation of the organism. Even when the embryo is made of only four cells, different species feature varying cellular arrangements: cells in mouse embryos arrange as a tetrahedron, in the nematode worm C. elegans cells make a diamond and in sea urchins cells arrange in a square configuration. How do cells in embryos of different species control their arrangements? Using computer simulations, we studied how cell divisions, physical contacts between cells and the confinement of the embryo by an eggshell affect the arrangements of cells when the embryos have only 4 cells. We find that the shape of the confining eggshell plays a key role in controlling the cell arrangements, removing unwanted arrangements and robustly specifying the proper contacts between cells. Our results highlight the important roles of embryonic confinement in establishing the proper cell-cell contacts as the embryo starts to develop.

scholarly journals Compensatory replacement of the BigH1 variant histone by canonical H1 supports normal embryonic development in Drosophila

2019 ◽  
Author(s):  
Kaili K. Li ◽  
Dongsheng Han ◽  
Fang Chen ◽  
Ruihao Li ◽  
Bing-Rui Zhou ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Histone H1 ◽  
Histone Variants ◽  
Linker Histone ◽  
Chromatin State ◽  
Biological Functions ◽  
Developmental Context ◽  
Early Embryos ◽  
Essential Function ◽  
Normal Embryonic Development

SummaryHistone variants carry specific functions in addition to those fulfilled by their canonical counterparts. Variants of the linker Histone H1 are prevalent in vertebrates and based on the pattern of their expression, many are presumed to function during germline and the earliest zygotic stages of development. While the existence of multiple H1 variants has hampered their study in vertebrates, a single variant, BigH1, was identified in Drosophila, promising to accelerate our understanding of the biological functions of H1 and H1 variants. Here we uncovered evidence for a compensatory activity that loads maternal H1 onto BigH1-devoid chromatin. Remarkably, this H1-based chromatin state is fully functional in supporting normal embryonic development, suggesting that H1 carries the essential function of the BigH1 molecule under the same developmental context. In addition, we discovered that this compensatory replacement of BigH1 with H1 might be limited to rapidly cycling cells in early embryos.

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