Poly U stimulation of single ribosomes and of ribosomes engaged in polysomes of sea urchin eggs and embryos

1. A cell-free system capable of using oxygen with oxalacetate as substrate has been prepared from both unfertilized and fertilized sea urchin eggs. The oxygen uptake by this system is about twice that of an equivalent quantity of intact unfertilized eggs and half that of an equivalent quantity of intact fertilized eggs. 2. The oxygen consumption of this cell-free oxidative system can be stimulated by addition of suitable concentrations of 4,6-dinitro-o-cresol or by inorganic phosphate. This confirms, with a cell-free system obtained from sea urchin eggs, the observations of Loomis and Lipmann regarding stimulation of oxygen consumption by a system obtained from rabbit kidney. 3. A preliminary but unsuccessful attempt has been made to determine the conditions under which cell-free, aerobic, phosphorylating systems may be obtained from either unfertilized or fertilized sea urchin eggs.

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Ca2+ influx and stimulation of protein synthesis in sea urchin eggs

Experimental Cell Research ◽

10.1016/0014-4827(83)90286-0 ◽

1983 ◽

Vol 147 (1) ◽

pp. 209-215 ◽

Cited By ~ 11

Author(s):

François Dubé ◽

Pierre Guerrier

Keyword(s):

Protein Synthesis ◽

Sea Urchin ◽

Sea Urchin Eggs ◽

Stimulation Of

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Stimulation of protein synthesis in unfertilized sea urchin eggs by prior metabolic inhibition

Biochemical and Biophysical Research Communications ◽

10.1016/s0006-291x(67)80001-9 ◽

1967 ◽

Vol 27 (4) ◽

pp. 425-430 ◽

Cited By ~ 16

Author(s):

F.R. MacKintosh ◽

Eugene Bell

Keyword(s):

Protein Synthesis ◽

Sea Urchin ◽

Metabolic Inhibition ◽

Sea Urchin Eggs ◽

Stimulation Of

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Guanosine 5'-thiotriphosphate may stimulate phosphoinositide messenger production in sea urchin eggs by a different route than the fertilizing sperm.

Cell Regulation ◽

10.1091/mbc.2.2.121 ◽

1991 ◽

Vol 2 (2) ◽

pp. 121-133 ◽

Cited By ~ 43

Author(s):

I Crossley ◽

T Whalley ◽

M Whitaker

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

G Protein ◽

Sea Urchin ◽

Calcium Transient ◽

Free Calcium ◽

Sea Urchin Eggs ◽

Kinase C ◽

Gamma S ◽

Stimulation Of

We show that microinjecting guanosine-5'-thiotriphosphate (GTP gamma S) into unfertilized sea urchin eggs generates an intracellular free calcium concentration [( Ca]i) transient apparently identical in magnitude and duration to the calcium transient that activates the egg at fertilization. The GTP gamma S-induced transient is blocked by prior microinjection of the inositol trisphosphate (InsP3) antagonist heparin. GTP gamma S injection also causes stimulation of the egg's Na+/H+ antiporter via protein kinase C, even in the absence of a [Ca]i increase. These data suggest that GTP gamma S acts by stimulating the calcium-independent production of the phosphoinositide messengers InsP3 and diacylglycerol (DAG). However, the fertilization [Ca]i transient is not affected by heparin, nor can the sperm cause calcium-independent stimulation of protein kinase C. It seems that the bulk of InsP3 and DAG production at fertilization is triggered by the [Ca]i transient, not by the sperm itself. GDP beta S, a G-protein antagonist, does not affect the fertilization [Ca]i transient. Our findings do not support the idea that signal transduction at fertilization operates via a G-protein linked directly to a plasma membrane sperm receptor.

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