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.

Synthesis of nuclear and cytoplasmic proteins in the early development of fishes and echinoderms

Development ◽  
1971 ◽  
Vol 26 (3) ◽  
pp. 611-622
Author(s):  
Maya R. Krigsgaber ◽  
Alla A. Kostomarova ◽  
Tamara A. Terekhova ◽  
Tatiana A. Burakova
Keyword(s):  
Amino Acids ◽  
Early Development ◽  
Sea Urchin ◽  
Nuclear Volume ◽  
Sea Urchin Embryos ◽  
Cytoplasmic Proteins ◽  
Specific Activities ◽  
Strongylocentrotus Nudus ◽  
Silver Grains ◽  
Misgurnus Fossilis

Synthesis of nuclear and cytoplasmic proteins was studied biochemically and autoradiographically in early loach (Misgurnus fossilis) and sea-urchin (Strongylocentrotus nudus) embryos. After incubation with [14C]amino acids for 5–120 min the ratio of the specific activities of nuclear, mitochondrial and 12000 g supernatant proteins was shown to be equal approximately to 6:1:2 in loach embryos and to 8:4:3 in sea-urchin embryos independently of the duration of labelling. After incubation with [3H]amino acids the number of silver grains per unit section was on the average 2·4 times higher for nuclei than it was for cytoplasm at mid-blastula and mid-gastrula stages. At the mid-gastrula the vegeto-animal gradient of protein synthesis was found. A higher level of the synthesis of nuclear proteins as compared with that of cytoplasmic proteins appears to be related to an increase in the nuclear volume and the nucleo-cytoplasmic ratio during the early development of the loach and sea-urchin embryos.

Displacement of Valine From Intact Sea-Urchin Eggs by Exogenous Amino Acids

1968 ◽  
Vol 3 (4) ◽  
pp. 515-527
Author(s):  
J. PIATIGORSKY ◽  
A. TYLER
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Sea Urchin ◽  
Sea Water ◽  
The Other ◽  
Metabolic Product ◽  
Primary Factor ◽  
Lytechinus Pictus ◽  
Sea Urchin Eggs ◽  
Neutral Amino Acids

Unfertilized and fertilized eggs of the sea urchin Lytechinus pictus were preloaded with [14C]valine and exposed to individual solutions of each of the twenty ‘coded’ [12C]amino acids in artificial sea water. After 1 h incubation the amount of radioactivity in the medium was determined. The radioactivity was effectively displaced by most of the other neutral [12C]amino acids that are known to compete with valine for uptake. A chromatographic test with fertilized eggs showed the displaced radioactivity to be [14C]valine and not some metabolic product. Addition of acidic, basic or some neutral amino acids that are known to be poor inhibitors of valine uptake did not cause significant quantities of label to appear in the medium. For the unfertilized eggs, the concentration of acid-soluble label remained many hundreds of times greater in the egg fluid than in the sea water. Tests indicated that efflux of [14C]valine and subsequent competition for re-entry is a primary factor responsible for the displacement phenomenon. That this may not be the sole factor is suggested by the fact that some amino acids that are known to be powerful inhibitors of valine uptake were found to be only weak displacers of [14C]valine. Neither [14C]arginine nor [14C]glutamic acid were displaced in significant amounts from preloaded unfertilized or fertilized eggs by any of the tested [12C]amino acids. Attempts were made to utilize the displacement of [12C]valine to elevate the incorporation of [14C]valine and of other labelled amino acids into protein by intact eggs. Unfertilized and fertilized eggs were pretreated with related [12C]amino acids and then exposed to [14C]valine or a mixture of [14C]amino acids. The results varied in the different tests, ranging from no significant increase to 2-fold.

scholarly journals ADP-ribosyltransferase in isolated nuclei from sea-urchin embryos

1985 ◽  
Vol 225 (2) ◽  
pp. 429-434 ◽  
Author(s):  
A Isoai ◽  
I Yasumasu
Keyword(s):  
Sea Urchin ◽  
Insoluble Fraction ◽  
Cell Stage ◽  
Isolated Nuclei ◽  
Sea Urchin Embryos ◽  
Snake Venom Phosphodiesterase ◽  
Km Value ◽  
Insoluble Product ◽  
Adp Ribosyltransferase ◽  
Hydrolysis Of

The activity of ADP-ribosyltransferase in nuclei isolated from sea-urchin embryos was estimated by the incorporation of [adenosine-14C]NAD+ into the acid-insoluble fraction. Hydrolysis of this acid-insoluble product by snake venom phosphodiesterase yielded radioactive 5′-AMP and phosphoribosyl-AMP. The incorporation of [14C]-NAD+ was inhibited by 3-aminobenzamide and nicotinamide, potent inhibitors of ADP-ribosyltransferase. [14C]NAD+ incorporation into the acid-insoluble fraction results from the reaction of ADP-ribosyltransferase. The optimum pH for the enzyme in isolated nuclei was 7.5. The enzyme, in 50 mM-Tris/HCl buffer, pH 7.5, containing 0.5 mM-NAD+ and 0.5 mM-dithiothreitol, exhibited the highest activity at 18 degrees C in the presence of 14 mM-MgCl2. The apparent Km value for NAD+ was 25 microM. The activity of the enzyme was measured in nuclei isolated from the embryos at several stages during early development. The activity was maximum at the 16-32-cell stage and then decreased to a minimum at the mesenchyme blastula stage. Thereafter its activity slightly increased at the onset of gastrulation and decreased again at the prism stage.

A measurement of the sequence complexity of polysomal messenger RNA in sea urchin embryos

Cell ◽  
1974 ◽  
Vol 2 (1) ◽  
pp. 9-21 ◽  
Author(s):  
Glenn A. Galau ◽  
Roy J. Britten ◽  
Eric H. Davidson
Keyword(s):  
Sea Urchin ◽  
Messenger Rna ◽  
Sea Urchin Embryos ◽  
Sequence Complexity

Polarized distribution of L-type calcium channels in early sea urchin embryos

1997 ◽  
Vol 273 (3) ◽  
pp. C822-C825 ◽  
Author(s):  
B. Dale ◽  
I. Yazaki ◽  
E. Tosti
Keyword(s):  
Steady State ◽  
Calcium Channels ◽  
Sea Urchin ◽  
Calcium Currents ◽  
Cleavage Division ◽  
Cell Stage ◽  
Developmental Defects ◽  
Calcium Dependent ◽  
Sea Urchin Embryos ◽  
M Phase

Using the whole cell clamp technique, we have measured calcium-dependent currents and steady-state conductance in early sea urchin blastomeres. The calcium currents in M phase decreased from 8.5 microA/cm2 at the four-cell stage to 5.4 microA/cm2 at the eight-cell stage. In 16-cell stage embryos, calcium currents were 7.4 microA/cm2 in the mesomeres, 2.3 microA/cm2 in the macromeres, and were not detected in the micromeres. In contrast, the micromeres had a two- to threefold higher steady-state conductance than the mesomeres or macromeres, which may be due to potassium ion conductivity. Nifedipine, an L-type channel antagonist, delays cleavage division at a concentration of 0.05-0.1 mM and causes developmental defects, such as poor skeletal differentiation in later sea urchin embryos.

scholarly journals β-Catenin is essential for patterning the maternally specified animal-vegetal axis in the sea urchin embryo

1998 ◽  
Vol 95 (16) ◽  
pp. 9343-9348 ◽  
Author(s):  
Athula H. Wikramanayake ◽  
Ling Huang ◽  
William H. Klein
Keyword(s):  
Sea Urchin ◽  
Molecular Mechanisms ◽  
Early Embryo ◽  
Cell Fates ◽  
Cell Stage ◽  
Signal Transduction Cascade ◽  
Sea Urchin Embryos ◽  
Sea Urchin Embryo ◽  
Vegetal Pole ◽  
Vegetal Cell

In sea urchin embryos, the animal-vegetal axis is specified during oogenesis. After fertilization, this axis is patterned to produce five distinct territories by the 60-cell stage. Territorial specification is thought to occur by a signal transduction cascade that is initiated by the large micromeres located at the vegetal pole. The molecular mechanisms that mediate the specification events along the animal–vegetal axis in sea urchin embryos are largely unknown. Nuclear β-catenin is seen in vegetal cells of the early embryo, suggesting that this protein plays a role in specifying vegetal cell fates. Here, we test this hypothesis and show that β-catenin is necessary for vegetal plate specification and is also sufficient for endoderm formation. In addition, we show that β-catenin has pronounced effects on animal blastomeres and is critical for specification of aboral ectoderm and for ectoderm patterning, presumably via a noncell-autonomous mechanism. These results support a model in which a Wnt-like signal released by vegetal cells patterns the early embryo along the animal–vegetal axis. Our results also reveal similarities between the sea urchin animal–vegetal axis and the vertebrate dorsal–ventral axis, suggesting that these axes share a common evolutionary origin.

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