Activator of G‐protein signaling in asymmetric cell divisions of the sea urchin embryo

Voronina, Ekaterina; Wessel, Gary M.

doi:10.1111/j.1440-169x.2006.00895.x

Cited by 19 publications

(17 citation statements)

References 31 publications

(90 reference statements)

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“…However, an intrinsic timing mechanism appears to exist since the vegetal cortex loses pigment granules during micromere formation at the 8 to 16-cell stage, even in cleavage arrested fertilized eggs (Schroeder, 1980). Concerning the molecular mechanism controlling UCD in sea urchin, an orthologue of the LGN/Pins protein was found to be involved (Voronina and Wessel, 2006). How the vegetal cortical enrichment of Pins/LGN is triggered at the 8-cell stage to cause UCD is not known, although it is tempting to speculate that it has something to do with the intrinsic timing mechanism that induces the loss of pigment granules from the vegetal cortex.…”

Section: Ucd In Sea Urchin (Cortical Pulling?)mentioning

confidence: 99%

Emergence of Embryo Shape During Cleavage Divisions

McDougall¹,

Chênevert²,

Godard³

et al. 2019

Results and Problems in Cell Differentiation

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Cells are arranged into species-specific patterns during early embryogenesis. Such cell division patterns are important since they often reflect the distribution of localized cortical factors from eggs/fertilized eggs to specific cells as well as the emergence of organismal form. However, it has proven difficult to reveal the mechanisms that underlie the emergence of cell positioning patterns that underlie embryonic shape, likely because a system-level approach is required that integrates cell biological, genetic, developmental and mechanical parameters. The choice of organism to address such questions is also important. Because ascidians display the most extreme form of invariant cleavage pattern amongst the metazoans, we have been analyzing the cell biological mechanisms that underpin three aspects of cell division (unequal cell division (UCD), oriented cell division (OCD), and asynchronous cell cycles) which affect the overall shape of the blastula-stage ascidian embryo composed of 64 cells. In ascidians, UCD creates two small cells at the 16-cell stage that in turn undergo two further successive rounds of UCD. Starting at the 16-cell stage, the cell cycle becomes asynchronous whereby the vegetal half divides before the animal half, thus creating 24, 32, 44 then 64-cell stages. Perturbing either UCD or the alternate cell division rhythm perturbs cell position. By analyzing cell shape, we discovered that cell shape propagates, via cell-cell contact, throughout the embryo following UCD and alternate/asynchronous cell division to create the ascidianspecific invariant cleavage pattern via OCD in the longest length of the apical surface of blastomeres.

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Section: Ucd In Sea Urchin (Cortical Pulling?)mentioning

confidence: 99%

Emergence of Embryo Shape During Cleavage Divisions

McDougall¹,

Chênevert²,

Godard³

et al. 2019

Results and Problems in Cell Differentiation

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show abstract

“…2012) which have rarely been combined with biochemical studies. This ambiguity applies to the potential role of protein kinases in regulation of ion channel permeability in the oocyte plasma membrane, heterotrimeric G protein activation in sea urchin oocytes (Voronina & Wessel 2006), as well as the fertilization-induced changes in Protein Tyrosine Kinase (PTK) signaling that occur in many marine invertebrate, fish, and amphibian oocytes(Giusti et al . 1999; Tokmakov et al .…”

Section: Introductionmentioning

confidence: 99%

Protein tyrosine kinase signaling in the mouse oocyte cortex during sperm–egg interactions and anaphase resumption

McGinnis

Luo

Kinsey

2013

Molecular Reproduction Devel

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Fertilization triggers activation of a series of pre-programmed signal transduction pathways in the oocyte that establish a block to polyspermy, induce meiosis resumption, and initiate zygotic development. The fusion between sperm and oocyte results in rapid changes in oocyte intracellular free calcium levels which in turn activate multiple protein kinase cascades in the ooplasm. The present study has examined the possibility that sperm-oocyte interaction involves localized activation of oocyte protein tyrosine kinases which could provide an alternative signaling mechanism triggered by the fertilizing sperm. Confocal immunofluorescence analysis with antibodies to phosphotyrosine and phosphorylated protein tyrosine kinases allowed detection of minute signaling events localized to the site of sperm-oocyte interaction that were not amenable to biochemical analysis. The results provide evidence for localized accumulation of phosphotyrosine at the site of sperm contact, binding, or fusion, which suggests active protein tyrosine kinase signaling prior to and during sperm incorporation. The PYK2 kinase was found to be concentrated and activated at the site of sperm-oocyte interaction and likely participates in this response. Widespread activation of PYK2 and FAK kinases was subsequently observed within the oocyte cortex indicating that sperm incorporation is followed by more global signaling by these kinases during meiosis resumption. The results demonstrate an alternating signaling pathway triggered in mammalian oocytes by sperm contact, binding, or fusion with the oocyte.

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“…This evidence includes pharmacological interference and dominant‐negative protein expression, both indicating that the heterotrimeric G protein Gi and its interaction partner, activator of G‐protein signaling (AGS), are necessary for the asymmetric cell divisions in many organisms such as Drosophila , C. elegans , and mammals (Morin and Bellaïche, ). The AGS/Pins (activator of G‐protein signaling/partner of inscuteable) family of proteins are conserved, multi‐domain molecular scaffolds found in many organisms from yeast to humans, and are reported to be involved in asymmetric cell divisions so far in Drosophila , C. elegans , and sea urchins (Schaefer et al, ; Betschinger and Knoblich, ; Voronina and Wessel, ; Park and Rose, ; Krueger et al, ; Morin and Bellaïche, ). In the sea urchin, inhibition of Gαi signaling by pertussis toxin interfered with micromere formation and led to defects in embryogenesis (Voronina and Wessel, ).…”

Section: Introductionmentioning

confidence: 99%

The biology of the germ line in echinoderms

Wessel

Brayboy

Fresques

et al. 2014

Molecular Reproduction Devel

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SUMMARY The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed.

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Activator of G‐protein signaling in asymmetric cell divisions of the sea urchin embryo

Cited by 19 publications

References 31 publications

Emergence of Embryo Shape During Cleavage Divisions

Emergence of Embryo Shape During Cleavage Divisions

Protein tyrosine kinase signaling in the mouse oocyte cortex during sperm–egg interactions and anaphase resumption

The biology of the germ line in echinoderms

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