Determination of cell fate in sea urchin embryos

BioEssays ◽  
1990 ◽  
Vol 12 (3) ◽  
pp. 115-119 ◽  
Author(s):  
Brian T. Livingston ◽  
Fred H. Wilt
Keyword(s):  
Cell Fate ◽  
Sea Urchin ◽  
Sea Urchin Embryos

scholarly journals Acquisition of the dorsal structures in chordate amphioxus

Open Biology ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 160062 ◽  
Author(s):  
Arseniy R. Morov ◽  
Tharcisse Ukizintambara ◽  
Rushan M. Sabirov ◽  
Kinya Yasui
Keyword(s):  
Sea Urchin ◽  
Striking Similarity ◽  
Sea Urchin Embryos ◽  
Profound Influence ◽  
Oral Ectoderm ◽  
The One ◽  
Gene Regulations ◽  
Present Understanding ◽  
Cortical Cytoskeleton

Acquisition of dorsal structures, such as notochord and hollow nerve cord, is likely to have had a profound influence upon vertebrate evolution. Dorsal formation in chordate development thus has been intensively studied in vertebrates and ascidians. However, the present understanding does not explain how chordates acquired dorsal structures. Here we show that amphioxus retains a key clue to answer this question. In amphioxus embryos, maternal nodal mRNA distributes asymmetrically in accordance with the remodelling of the cortical cytoskeleton in the fertilized egg, and subsequently lefty is first expressed in a patch of blastomeres across the equator where wnt8 is expressed circularly and which will become the margin of the blastopore. The lefty domain co-expresses zygotic nodal by the initial gastrula stage on the one side of the blastopore margin and induces the expression of goosecoid , not-like, chordin and brachyury1 genes in this region, as in the oral ectoderm of sea urchin embryos, which provides a basis for the formation of the dorsal structures. The striking similarity in the gene regulations and their respective expression domains when comparing dorsal formation in amphioxus and the determination of the oral ectoderm in sea urchin embryos suggests that chordates derived from an ambulacrarian-type blastula with dorsoventral inversion.

Ca(2+) in specification of vegetal cell fate in early sea urchin embryos

2001 ◽  
Vol 204 (5) ◽  
pp. 823-834
Author(s):  
I. Yazaki
Keyword(s):  
Cell Fate ◽  
Sea Urchin ◽  
Small Cells ◽  
Beta Catenin ◽  
Cell Stage ◽  
Sea Urchin Embryos ◽  
Mesoderm Specification ◽  
New Findings ◽  
Vegetal Pole ◽  
Vegetal Cell

In sea urchin embryos, the first specification of cell fate occurs at the fourth cleavage, when small cells (the micromeres) are formed at the vegetal pole. The fate of other blastomeres is dependent on the receipt of cell signals originating from the micromeres. The micromeres are fated to become skeletogenic cells and show the ability to induce the endoderm (the archenteron) in the neighbouring cells during the 16- to 60-cell stage. Several molecules involved in signaling pathways, i.e. Notch for mesoderm specification, bone morphogenic protein (BMP) for ectoderm specification and beta-catenin for endoderm specification, are spatially and temporally expressed during development. In the micromeres, beta-catenin increases and subsequently localizes to the nuclei under the regulation of TCF, a nuclear binding partner of beta-catenin, until the 60-cell stage. However, the mechanisms activating these signaling substances are still unclear. In this article, I demonstrate some specific properties of the membrane and cytoplasm of micromeres including new findings on intracellular Ca(2+) concentration, and propose a mechanism by which the functional micromeres are autonoumously formed. The possible roles of these in the specification of vegetal cell fate in early development are discussed.

Altered cell fate in LiCl-treated sea urchin embryos

1991 ◽  
Vol 147 (2) ◽  
pp. 445-450 ◽  
Author(s):  
Catherine Nocente-McGrath ◽  
Robert McIsaac ◽  
Susan G. Ernst
Keyword(s):  
Cell Fate ◽  
Sea Urchin ◽  
Sea Urchin Embryos ◽  
Altered Cell

scholarly journals SYNTHESIS AND STORAGE OF MICROTUBULE PROTEINS BY SEA URCHIN EMBRYOS

1971 ◽  
Vol 50 (2) ◽  
pp. 516-528 ◽  
Author(s):  
Rudolf A. Raff ◽  
Gerald Greenhouse ◽  
Kenneth W. Gross ◽  
Paul R. Gross
Keyword(s):  
Amino Acids ◽  
Sea Urchin ◽  
Messenger Rna ◽  
Binding Activity ◽  
Total Soluble Protein ◽  
Cell Stage ◽  
Lytechinus Pictus ◽  
Sea Urchin Embryos ◽  
Tritiated Amino Acids ◽  
Vinblastine Sulfate

Studies employing colchicine binding, precipitation with vinblastine sulfate, and acrylamide gel electrophoresis confirm earlier proposals that Arbacia punctulata and Lytechinus pictus eggs and embryos contain a store of microtubule proteins. Treatment of 150,000 g supernatants from sea urchin homogenates with vinblastine sulfate precipitates about 5% of the total soluble protein, and 75% of the colchicine-binding activity. Electrophoretic examination of the precipitate reveals two very prominent bands. These have migration rates identical to those of the A and B microtubule proteins of cilia. These proteins can be made radioactive at the 16 cell stage and at hatching by pulse labeling with tritiated amino acids. By labeling for 1 hr with leucine-3H in early cleavage, then culturing embryos in the presence of unlabeled leucine, removal of newly synthesized microtubule proteins from the soluble pool can be demonstrated. Incorporation of labeled amino acids into microtubule proteins is not affected by culturing embryos continuously in 20 µg/ml of actinomycin D. Microtubule proteins appear, therefore, to be synthesized on "maternal" messenger RNA. This provides the first protein encoded by stored or "masked" mRNA in sea urchin embryos to be identified.

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