Cell-specific regulation of protein synthesis in the sea urchin gastrula: A two-dimensional electrophoretic study

1982 ◽  
Vol 93 (2) ◽  
pp. 453-462 ◽  
Author(s):  
Michael A. Harkey ◽  
Arthur H. Whiteley
Keyword(s):  
Protein Synthesis ◽  
Sea Urchin ◽  
Two Dimensional ◽  
Electrophoretic Study ◽  
Specific Regulation

scholarly journals Electrophoretic analysis of the stored histone pool in unfertilized sea urchin eggs: quantification and identification by antibody binding.

1981 ◽  
Vol 90 (2) ◽  
pp. 385-395 ◽  
Author(s):  
J Salik ◽  
L Herlands ◽  
H P Hoffmann ◽  
D Poccia
Keyword(s):  
Protein Synthesis ◽  
Sea Urchin ◽  
Electrophoretic Analysis ◽  
Histone Variants ◽  
Two Dimensional ◽  
Cleavage Stage ◽  
Sea Urchin Eggs ◽  
Highly Sensitive ◽  
Immunological Technique ◽  
Electrophoretic Transfer

A maternal store of histones in unfertilized sea urchin eggs is demonstrated by two independent criteria. Stored histones are identified by their ability to assemble into chromatin of male pronuclei of fertilized sea urchin eggs in the absence of protein synthesis, suggesting a minimum of at least 25 haploid equivalents for each histone present and functional in the unfertilized egg. In addition, electrophoretic analysis of proteins from acid extracts of unfertilized whole eggs and enucleated merogons reveals protein spots comigrating with cleavage stage histone standards, though not with other histone variants found in later sea urchin development or in sperm. Quantification of the amount of protein per histone spot yields an estimate of several hundred haploid DNA equivalents per egg of stored histone. The identity of some of the putative histones was verified by a highly sensitive immunological technique, involving electrophoretic transfer of proteins from the two-dimensional polyacrylamide gels to nitrocellulose filters. Proteins in amounts less than 2 x 10(-4) micrograms can be detected by this method.

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

Stabilization of tubulin mRNA by inhibition of protein synthesis in sea urchin embryos

1988 ◽  
Vol 8 (8) ◽  
pp. 3518-3525
Author(s):  
Z Y Gong ◽  
B P Brandhorst
Keyword(s):  
Protein Synthesis ◽  
Sea Urchin ◽  
Mrna Stability ◽  
Rna Synthesis ◽  
Rapid Loss ◽  
Transcription Analysis ◽  
Inhibition Of Protein Synthesis ◽  
Tubulin Mrna ◽  
Autogenous Regulation

An increased level of unpolymerized tubulin caused by depolymerization of microtubules in sea urchin larvae resulted in a rapid loss of tubulin mRNA, which was prevented by nearly complete inhibition of protein synthesis. Results of an RNA run-on assay indicated that inhibition of protein synthesis does not alter tubulin gene transcription. Analysis of the decay of tubulin mRNA in embryos in which RNA synthesis was inhibited by actinomycin D indicated that inhibition of protein synthesis prevents the destabilization of tubulin mRNA. The effect was similar whether mRNA was maintained on polysomes in the presence of emetine or anisomycin or displaced from the polysomes in the presence of puromycin or pactamycin; thus, the stabilization of tubulin mRNA is not dependent on the state of the polysomes after inhibition of protein synthesis. Even after tubulin mRNA declined to a low level after depolymerization of microtubules, it could be rescued by treatment of embryos with inhibitors of protein synthesis. Tubulin mRNA could be induced to accumulate prematurely in gastrulae but not in plutei if protein synthesis was inhibited, an observation that is indicative of the importance of the autogenous regulation of tubulin mRNA stability during embryogenesis. Possible explanations for the role of protein synthesis in the control of mRNA stability are discussed.

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