scholarly journals miR-424-5p reduces ribosomal RNA and protein synthesis in muscle wasting

2017 ◽  
Vol 9 (2) ◽  
pp. 400-416 ◽  
Author(s):  
Martin Connolly ◽  
Richard Paul ◽  
Roser Farre-Garros ◽  
Samantha A. Natanek ◽  
Susannah Bloch ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Rna ◽  
Muscle Wasting ◽  
Rna And Protein Synthesis

scholarly journals THE EFFECTS OF INHIBITORS OF RNA AND PROTEIN SYNTHESIS ON THE RECOVERY OF CHLOROPLAST RIBOSOMES, MEMBRANE ORGANIZATION, AND PHOTOSYNTHETIC ELECTRON TRANSPORT IN THE ac-20 STRAIN OF CHLAMYDOMONAS REINHARDI

1971 ◽  
Vol 50 (1) ◽  
pp. 50-62 ◽  
Author(s):  
Ursula W. Goodenough ◽  
R. P. Levine
Keyword(s):  
Protein Synthesis ◽  
Electron Transport ◽  
Chloroplast Dna ◽  
Ribosomal Rna ◽  
Structural Integrity ◽  
Photosynthetic Electron Transport ◽  
Rna And Protein Synthesis ◽  
Low Levels ◽  
Inhibitor Of Protein Synthesis ◽  
Secondary Consequence

The ac-20 strain of Chlamydomonas reinhardi is characterized by low levels of chloroplast ribosomes when grown mixotrophically. Cells can be transferred to minimal medium and their ribosome levels increase. If, at the time of transfer, cells are exposed to chloramphenicol, an inhibitor of protein synthesis in the chloroplast, or cycloheximide, an inhibitor of protein synthesis in the cytoplasm, ribosome recovery is not affected; however, recovery is blocked by exposure to rifampicin, an inhibitor of chloroplast DNA-dependent RNA polymerase. It is therefore concluded that ac-20 cells suffer from an impaired chloroplast ribosomal RNA synthesis. Mixotrophic ac-20 cells are also characterized by low rates of photosynthetic electron transport, disorganized chloroplast membranes, and a small pyrenoid. If chloramphenicol is applied to transferred cells whose chloroplast ribosome levels have already recovered, recovery of photosynthetic electron transport and of structural integrity does not occur. Under the same conditions, cycloheximide has no effect on recovery. It is concluded that the structural and photosynthetic lesions in ac-20 are a secondary consequence of the low levels of chloroplast ribosomes. Finally, we present evidence that recovery of photosynthetic electron transport requires the transcription of chloroplast DNA. This transcription is apparently triggered by light.

Changes in Ribosome Organization and Messenger RNA Abundance in Ripening Tomato Fruits

1984 ◽  
Vol 11 (3) ◽  
pp. 225 ◽  
Author(s):  
J Spiers ◽  
CJ Brady ◽  
D Grierson ◽  
E Lee
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Rna ◽  
Messenger Rna ◽  
In Vitro Translation ◽  
Translation System ◽  
Active Protein ◽  
Tomato Fruits ◽  
Rna And Protein Synthesis ◽  
Early Ripening

The involvement of RNA and protein synthesis in fruit ripening was investigated. Mature-green tomato fruits were found to contain about 30% of their ribosomal RNA in polyribosomes. At the 'breaker' or early ripening stage, about 50% of rRNA was in polyribosomes and this distribution of rRNA was maintained until fruits were fully ripe. The continued presence of polyribosomes is consistent with active protein synthesis persisting through and beyond the climacteric period when the wall-hydrolysing enzyme polygalacturonase accumulates and fruits soften, synthesize lycopene and undergo other ripening related changes. Poly(A)-containing RNA purified from polyribosomes extracted from individual fruits was used to prime the synthesis of [35S]methionine-labelled polypeptides by a wheat germ in vitro translation system. The pattern of polypeptides synthesized in response to RNA from mature-green fruits differed from that given by RNA from ripening fruits. The majority of changes were found to occur within approximately 48 h of the increase of ethylene synthesis and were apparent in all fruits with any pink or red colour. Similar results were obtained by translating total cellular RNA and total polyribosomal RNA indicating that the major RNA species shown in this study to change in abundance during ripening are polyadenylated, and hence most probably cytoplasmic, and do not accumulate as 'stored messages' outside of the polyribosomes. The differences between green and ripening fruits in polyribosome profiles were demonstrated in two cultivars of tomato. Differences in mRNA populations between green and ripe fruits were found in three cultivars.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

scholarly journals Identical 3′-terminal octanucleotide sequence in 18S ribosomal ribonucleic acid from different eukaryotes. A proposed role for this sequence in the recognition of terminator codons

1974 ◽  
Vol 141 (3) ◽  
pp. 609-615 ◽  
Author(s):  
John Shine ◽  
Lynn Dalgarno
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Base Sequence ◽  
Terminal Sequence ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species

The 3′-terminal sequence of 18S ribosomal RNA from Drosophila melanogaster and Saccharomyces cerevisiae was determined by stepwise degradation from the 3′-terminus and labelling with [3H]isoniazid. The sequence G-A-U-C-A-U-U-AOH was found at the 3′-terminus of both 18S rRNA species. Less extensive data for 18S RNA from a number of other eukaryotes are consistent with the same 3′-terminal sequence, and an identical sequence has previously been reported for the 3′-end of rabbit reticulocyte 18S rRNA (Hunt, 1970). These results suggest that the base sequence in this region is strongly conserved and may be identical in all eukaryotes. As the 3′-terminal hexanucleotide is complementary to eukaryotic terminator codons we discuss the possibility that the 3′-end of 18S rRNA may have a direct base-pairing role in the termination of protein synthesis.

A Method of Maintaining Parenchymal Cells from Adult Rat Liver In Vitro

1972 ◽  
Vol 11 (1) ◽  
pp. 249-260
Author(s):  
J. ALWEN ◽  
JENNIFER J. GALLHAI-ATCHARD
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Protein Synthesis ◽  
Light And Electron Microscopy ◽  
Rat Hepatocytes ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Rna And Protein Synthesis ◽  
Parenchymal Cells

A method for preparing suspensions of adult rat hepatocytes suitable for maintenance in vitro is described. Cultures were established from the cell suspensions by the squash technique. Cells were examined by light and electron microscopy; histochemically for glycogen, bile, lipid and glucose-6-phosphatase; and by autoradiography for DNA, RNA and protein synthesis. Hepatocytes could be maintained in vitro for at least 3 days and began to aggregate after 1 day. Uridine and leucine were incorporated, but not thymidine. Cultures consisted mainly of hepatocytes, though reticulo-endothelial cells were sometimes present.

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