scholarly journals Dependence of nucleus-directed rRNA synthesis upon mitochondrial protein synthesis in Tetrahymena.

1982 ◽  
Vol 2 (5) ◽  
pp. 508-516 ◽  
Author(s):  
L Ruben ◽  
A B Hooper
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Mitochondrial Protein ◽  
Tetrahymena Pyriformis ◽  
Cellular Protein ◽  
Rrna Synthesis ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Rrna ◽  
Polyadenylated Rna ◽  
Nuclear Rna

The antibiotic chloramphenicol selectively inhibited mitochondrial protein synthesis in the ciliate protozoan Tetrahymena pyriformis GL. Secondary to the inhibition of mitochondrial protein synthesis was an inhibition of nuclear RNA synthesis at a time before inhibition of cellular protein and DNA synthesis. Of the stable non-polyadenylated RNA species in Tetrahymena, the addition of chloramphenicol resulted specifically in the inhibition of synthesis of 28S + 17S and 5S rRNA transcripts. By contrast, syntheses of 4S tRNA and 21S mitochondrial rRNA were not as extensively inhibited. The addition of 60 microM hemin before the addition of chloramphenicol partially protected against the inhibition of RNA synthesis. These data indicate that continued synthesis of nucleus-directed rRNA is linked to the synthesis of mitochondrial proteins in Tetrahymena.

Dependence of nucleus-directed rRNA synthesis upon mitochondrial protein synthesis in Tetrahymena

1982 ◽  
Vol 2 (5) ◽  
pp. 508-516
Author(s):  
L Ruben ◽  
A B Hooper
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Mitochondrial Protein ◽  
Tetrahymena Pyriformis ◽  
Cellular Protein ◽  
Rrna Synthesis ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Rrna ◽  
Polyadenylated Rna ◽  
Nuclear Rna

The antibiotic chloramphenicol selectively inhibited mitochondrial protein synthesis in the ciliate protozoan Tetrahymena pyriformis GL. Secondary to the inhibition of mitochondrial protein synthesis was an inhibition of nuclear RNA synthesis at a time before inhibition of cellular protein and DNA synthesis. Of the stable non-polyadenylated RNA species in Tetrahymena, the addition of chloramphenicol resulted specifically in the inhibition of synthesis of 28S + 17S and 5S rRNA transcripts. By contrast, syntheses of 4S tRNA and 21S mitochondrial rRNA were not as extensively inhibited. The addition of 60 microM hemin before the addition of chloramphenicol partially protected against the inhibition of RNA synthesis. These data indicate that continued synthesis of nucleus-directed rRNA is linked to the synthesis of mitochondrial proteins in Tetrahymena.

The relationship of cardiolipin biosynthesis to mitochondrial protein synthesis in Tetrahymena pyriformis

1983 ◽  
Vol 61 (4) ◽  
pp. 223-228 ◽  
Author(s):  
Sean M. Hemmingsen ◽  
Laura Querengesser ◽  
Paul G. Young
Keyword(s):  
Protein Synthesis ◽  
Stationary Phase ◽  
Mitochondrial Protein ◽  
Tetrahymena Pyriformis ◽  
Pulse Labelling ◽  
Mitochondrial Protein Synthesis ◽  
Mole Percent ◽  
Quantitative Measurements ◽  
Relationship Of ◽  
The Relationship

The synthesis of cardiolipin has been investigated following the inhibition of mitochondrial protein synthesis with chloramphenicol. Quantitative measurements of the amount of cardiolipin in the cell during treatment with chloramphenicol as well as pulse-labelling studies using labelled acetate were carried out. The results show that while whole cell phospholipid biosynthesis is depressed by the treatment (probably a reflection of a general cessation of growth), there is no sign of any preferential effect on cardiolipin synthesis. The data also show that as cells are reduced in size as they approach stationary phase there is a six- to seven-fold loss of total cellular phospholipids; however, the amount of cardiolipin is only reduced by four- to five-fold. There is a preferential conservation of cardiolipin as stationary phase is approached with the mole percent cardiolipin phosphorus in the cell rising from 5–7% to 10–12%.

Decreased total ventricular and mitochondrial protein synthesis during extended anoxia in turtle heart

1996 ◽  
Vol 271 (6) ◽  
pp. R1660-R1667 ◽  
Author(s):  
J. R. Bailey ◽  
W. R. Driedzic
Keyword(s):  
Protein Synthesis ◽  
Energy Levels ◽  
Mitochondrial Protein ◽  
Atp Synthesis ◽  
Cellular Protein ◽  
Control Mechanisms ◽  
Mitochondrial Protein Synthesis ◽  
Available Energy ◽  
Pressure Development ◽  
Turtle Heart

The turtle heart provides a model system to study the effects of anoxia on protein synthesis without the potentially confounding factor of contractile failure and decreased ATP levels. Protein synthesis, as measured by 3H-labeled phenylalanine incorporation, was studied under conditions of normoxia and anoxia in isolated perfused turtle [Trachemys (= Pseudemys) scripta elegans] hearts at 15 degrees C. Heart rate, cardiac output, and ventricular pressure development were unaffected by 2 or 3 h of anoxia. Despite the anoxia, energy levels in the heart were presumably still high, since contractility was maintained. RNA content of ventricle decreased after anoxic perfusion. Rates of total protein synthesis rates in ventricle were threefold lower under anoxia than under normoxia. These findings suggest that the total level of RNA is one determinant of protein synthesis. Incorporation of label into protein extracted from mitochondria was also assessed. The ratio of mitochondrial to whole ventricular protein synthesis was significantly lower after anoxia, revealing preferential control mechanisms under anoxia between the synthesis of total cellular protein and protein destined for mitochondria. Isolated mitochondria were still coupled after 2 or 3 h of anoxia. In effect, the mitochondria enter into a state of hypometabolism in terms of rates of ATP synthesis and protein synthesis, but functional integrity is maintained. The decrease in protein synthesis in general and mitochondrial protein synthesis in particular may represent an adaptation to allow the partitioning of the available energy resources toward mechanical function during anoxia.

scholarly journals Bovine mitochondrial protein synthesis elongation factors

1989 ◽  
Vol 264 (32) ◽  
pp. 19125-19131
Author(s):  
C J Schwartzbach ◽  
L L Spremulli
Keyword(s):  
Protein Synthesis ◽  
Mitochondrial Protein ◽  
Mitochondrial Protein Synthesis ◽  
Elongation Factors

scholarly journals Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 674
Author(s):  
Francesco Capriglia ◽  
Francesca Rizzo ◽  
Giuseppe Petrosillo ◽  
Veronica Morea ◽  
Giulia d’Amati ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Molecular Mechanisms ◽  
Mitochondrial Protein ◽  
Trna Synthetase ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Translation ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Mitochondrial Functions ◽  
Carboxy Terminal

The m.3243A>G mutation within the mitochondrial mt-tRNALeu(UUR) gene is the most prevalent variant linked to mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. This pathogenic mutation causes severe impairment of mitochondrial protein synthesis due to alterations of the mutated tRNA, such as reduced aminoacylation and a lack of post-transcriptional modification. In transmitochondrial cybrids, overexpression of human mitochondrial leucyl-tRNA synthetase (LARS2) has proven effective in rescuing the phenotype associated with m.3243A>G substitution. The rescuing activity resides in the carboxy-terminal domain (Cterm) of the enzyme; however, the precise molecular mechanisms underlying this process have not been fully elucidated. To deepen our knowledge on the rescuing mechanisms, we demonstrated the interactions of the Cterm with mutated mt-tRNALeu(UUR) and its precursor in MELAS cybrids. Further, the effect of Cterm expression on mitochondrial functions was evaluated. We found that Cterm ameliorates de novo mitochondrial protein synthesis, whilst it has no effect on mt-tRNALeu(UUR) steady-state levels and aminoacylation. Despite the complete recovery of cell viability and the increase in mitochondrial translation, Cterm-overexpressing cybrids were not able to recover bioenergetic competence. These data suggest that, in our MELAS cell model, the beneficial effect of Cterm may be mediated by factors that are independent of the mitochondrial bioenergetics.

The effect of inhibition of mitochondrial protein synthesis on the proliferation and phenotypic properties of a rat leukemia in different stages of in-vivo tumor development

1987 ◽  
Vol 11 (6) ◽  
pp. 529-536 ◽  
Author(s):  
Coby Van den Bogert ◽  
Bert H.J. Dontje ◽  
Štefan Kuẑela ◽  
Trudi E. Melis ◽  
Davine Opstelten ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Mitochondrial Protein ◽  
Tumor Development ◽  
Mitochondrial Protein Synthesis ◽  
Phenotypic Properties
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