scholarly journals Mitochondrial and cytoplasmic ribosomes. Distinguishing characteristics and a requirement for the homologous ribosomal saltextractable fraction for protein synthesis

1974 ◽  
Vol 140 (1) ◽  
pp. 73-78 ◽  
Author(s):  
N. G. Avadhani ◽  
D. E. Buetow
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Euglena Gracilis ◽  
High Specificity ◽  
5S Rna ◽  
Cell Compartment ◽  
Total Rna ◽  
Mitochondrial Ribosomes ◽  
Cytoplasmic Ribosomes

1. Mitochondrial and cytoplasmic ribosomes of Euglena gracilis differ in their total RNA and protein content. 2. Mitochondrial ribosomes dissociate to subunits at higher Mg2+concentrations than do cytoplasmic ribosomes. 3. A separable 5S RNA is obtained from cytoplasmic and chloroplast ribosomes, but not from mitochondrial ribosomes. 4. For protein-synthesizing activity with a natural mRNA, mitochondrial ribosomes use tRNA from any cell compartment and are partly active with supernatant enzymes from cytoplasm. Cytoplasmic ribosomes are partly active with enzymes and tRNA from mitochondria or chloroplasts. 5. Both mitochondrial and cytoplasmic ribosomes show high specificity for the homologous salt-extractable ribosomal fraction for protein-synthesizing activity.

scholarly journals Studies on S-adenosylmethionine–magnesium protoporphyrin methyltransferase in Euglena gracilis strain Z

1969 ◽  
Vol 111 (4) ◽  
pp. 573-582 ◽  
Author(s):  
Jean G. Ebbon ◽  
G. H. Tait
Keyword(s):  
Protein Synthesis ◽  
Euglena Gracilis ◽  
Tween 80 ◽  
Cytoplasmic Protein ◽  
Cytoplasmic Ribosomes ◽  
Chloroplast Fraction ◽  
In Cells

1. An enzyme that methylates magnesium protoporphyrin was detected in extracts of light-grown and dark-grown cells of Euglena gracilis. The activity in light-grown cells is two to three times that in cells grown in the dark. 2. The activity is mainly located in the chloroplast fraction from light-grown cells and in proplastids in dark-grown cells. However, in cells grown either in the light or dark, about 15–20% is found in particle-free supernatant. 3. The chloroplast methylating enzyme was solubilized by the action of Tween 80 and partially purified. The properties were investigated. 4. From experiments in which etiolated cells were illuminated in the presence of inhibitors of chloroplast or cytoplasmic protein synthesis, it appears that the methylating enzyme is made on cytoplasmic ribosomes.

Cycloheximide and heat shock induce new polypeptide synthesis in Neurospora crassa

1982 ◽  
Vol 2 (10) ◽  
pp. 1167-1173
Author(s):  
J Perlman ◽  
J F Feldman
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Neurospora Crassa ◽  
Temperature Shift ◽  
Molecular Weights ◽  
Mitochondrial Ribosomes ◽  
New Synthesis ◽  
Mechanisms Of Adaptation ◽  
Cytoplasmic Ribosomes ◽  
Polypeptide Band

Treatment of Neurospora crassa with 0.1 microgram of cycloheximide per ml, a concentration which inhibited protein synthesis by about 70%, resulted in the greatly enhanced synthesis of at least three polypeptide bands with estimated molecular weights of 88,000, 30,000, and 28,000. A temperature shift from 25 to 37 degrees C resulted in the appearance of a single new polypeptide band of 70,000 daltons, the same size as the major heat shock-induced proteins observed in species of Drosophila and Dictyostelium. Synthesis of the cycloheximide-stimulated polypeptide bands was on cytoplasmic ribosomes rather than on mitochondrial ribosomes, as incorporation of isotope into the polypeptide bands was inhibited by 1.0 microgram of cycloheximide per ml but not by 1 mg of chloramphenicol per ml. In a mutant with cycloheximide-resistant ribosomes, 0.1 microgram of cycloheximide per ml failed to alter the pattern of protein synthesis from that of the controls. It is suggested that the new synthesis of the polypeptide bands reflects specific mechanisms of adaptation to different kinds of environmental stress, including inhibition of protein synthesis and temperature increases.

scholarly journals Cycloheximide and heat shock induce new polypeptide synthesis in Neurospora crassa.

1982 ◽  
Vol 2 (10) ◽  
pp. 1167-1173 ◽  
Author(s):  
J Perlman ◽  
J F Feldman
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Neurospora Crassa ◽  
Temperature Shift ◽  
Molecular Weights ◽  
Mitochondrial Ribosomes ◽  
New Synthesis ◽  
Mechanisms Of Adaptation ◽  
Cytoplasmic Ribosomes ◽  
Polypeptide Band

Treatment of Neurospora crassa with 0.1 microgram of cycloheximide per ml, a concentration which inhibited protein synthesis by about 70%, resulted in the greatly enhanced synthesis of at least three polypeptide bands with estimated molecular weights of 88,000, 30,000, and 28,000. A temperature shift from 25 to 37 degrees C resulted in the appearance of a single new polypeptide band of 70,000 daltons, the same size as the major heat shock-induced proteins observed in species of Drosophila and Dictyostelium. Synthesis of the cycloheximide-stimulated polypeptide bands was on cytoplasmic ribosomes rather than on mitochondrial ribosomes, as incorporation of isotope into the polypeptide bands was inhibited by 1.0 microgram of cycloheximide per ml but not by 1 mg of chloramphenicol per ml. In a mutant with cycloheximide-resistant ribosomes, 0.1 microgram of cycloheximide per ml failed to alter the pattern of protein synthesis from that of the controls. It is suggested that the new synthesis of the polypeptide bands reflects specific mechanisms of adaptation to different kinds of environmental stress, including inhibition of protein synthesis and temperature increases.

Total RNA and protein content, Cyclin B1 expression and developmental competence of prepubertal goat oocytes

2008 ◽  
Vol 103 (3-4) ◽  
pp. 290-303 ◽  
Author(s):  
Begoña Anguita ◽  
Maria-Teresa Paramio ◽  
Ana R. Jiménez-Macedo ◽  
Roser Morató ◽  
Teresa Mogas ◽  
...  
Keyword(s):  
Protein Content ◽  
Cyclin B1 ◽  
Developmental Competence ◽  
Total Rna

Total protein content and protein synthesis within pre-elongation stage bovine embryos

1998 ◽  
Vol 50 (2) ◽  
pp. 139-145 ◽  
Author(s):  
J.G. Thompson ◽  
A.N.M. Sherman ◽  
N.W. Allen ◽  
L.T. McGowan ◽  
H.R. Tervit
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Total Protein ◽  
Total Protein Content ◽  
Bovine Embryos

The route of entry of cytoplasmically synthesized proteins into chloroplasts of algae possessing chloroplast ER

1979 ◽  
Vol 35 (1) ◽  
pp. 253-266
Author(s):  
S.P. Gibbs
Keyword(s):  
Protein Synthesis ◽  
Nuclear Envelope ◽  
Outer Membrane ◽  
Chloroplast Envelope ◽  
Inhibit Protein Synthesis ◽  
Ochromonas Danica ◽  
Plastid Proteins ◽  
Regular Network ◽  
Cytoplasmic Ribosomes ◽  
Plastid Ribosomes

In 8 classes of algae, namely the Cryptophyceae, Raphidophyceae, Haptophyceae, Chrysophyceae, Bacillariophyceae, Xanthophyceae, Eustigmatophyceae and Phaeophyceae, the chloroplasts, in addition to being surrounded by a double-membraned chloroplast envelope, are also enclosed by a cisterna of endoplasmic reticulum called the chloroplast ER. Often this ER cisterna is continuous with the outher membrane of the nuclear envelope in such a manner that the nuclear envelope forms a part of the ER sac enclosing the chloroplast. In all these classes of algae except the Cryptophyceae, a regular network of tubules and vesicles, named the periplastidal reticulum, is present at a specific location between the chloroplast envelope and the chloroplast ER. In the Cryptophyceae, scattered vesicles are found between the chloroplast envelope and the chloroplast ER. Ribosomes which have been shown to be arranged to polysomes are found on the outer membrane of the chloroplast ER. It is proposed that nuclear-coded proteins which are destined for the chloroplast are synthesized on these polysomes, passing during synthesis into the lumen of the ER cisterna. Vesicles containing these proteins then pinch off the chloroplast ER and form the periplastidal reticulum. Vesicles containing these proteins then pinch off the chloroplast ER and form the periplastidal reticulum. Vesicles then fuse with the outer membrane of the chloroplast envelope thereby delivering their contents to the lumen of the chloroplast envelope. Proteins then cross the inner membrane of the chloroplast envelope in an as yet unknown manner. Experimental evidence for this hypothesis comes from studies on Ochromonas danica using chloramphenicol and spectinomycin, which inhibit protein synthesis on plastid ribosomes, and cycloheximide, which inhibits protein synthesis on cytoplasmic ribosomes. In cells of Ochromonas exposed to chloramphenicol or spectinomycin, the periplastidal reticulum proliferates markedly becoming several layers thick. Presumably this build up of periplastidal reticulum occurs because the transport of cytoplasmically synthesized plastid proteins is slowed down when protein synthesis in the chloroplast is inhibited. Conversely, when cells of Ochromonas are treated with cycloheximide, there is a reduction in the amount of periplastidal reticulum presumably because there are no cytoplasmically synthesized proteins to be transported into the chloroplast.

scholarly journals Tagging of RPS9 as a tool for ribosome purification and identification of ribosome-associated proteins

2020 ◽  
pp. 57-57
Author(s):  
Bogdan Jovanovic ◽  
Lisa Schubert ◽  
Fabian Poetz ◽  
Georg Stoecklin
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Proteins ◽  
Associated Factors ◽  
Ribosomal Subunit ◽  
High Specificity ◽  
Negative Control ◽  
Tev Protease ◽  
Protease Cleavage ◽  
Associated Proteins ◽  
And Function

Ribosomes, the catalytic machinery required for protein synthesis, are comprised of 4 ribosomal RNAs and about 80 ribosomal proteins in mammals. Ribosomes further interact with numerous associated factors that regulate their biogenesis and function. As mutations of ribosomal proteins and ribosome associated proteins cause many diseases, it is important to develop tools by which ribosomes can be purified efficiently and with high specificity. Here, we designed a method to purify ribosomes from human cell lines by C-terminally tagging human RPS9, a protein of the small ribosomal subunit. The tag consists of a flag peptide and a streptavidin-binding peptide (SBP) separated by the tobacco etch virus (TEV) protease cleavage site. We demonstrate that RPS9-Flag-TEV-SBP (FTS) is efficiently incorporated into the ribosome without interfering with regular protein synthesis. Using HeLa-GFP-G3BP1 cells stably expressing RPS9-FTS or, as a negative control, mCherry-FTS, we show that complete ribosomes as well as numerous ribosome-associated proteins are efficiently and specifically purified following pull-down of RPS9-FTS using streptavidin beads. This tool will be helpful for the characterization of human ribosome heterogeneity, post-translational modifications of ribosomal proteins, and changes in ribosome-associated factors after exposing human cells to different stimuli and conditions.

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