scholarly journals Messenger RNA and the Endoplasmic Reticulum

Nature ◽  
1971 ◽  
Vol 233 (5320) ◽  
pp. 448-448
Keyword(s):  
Endoplasmic Reticulum ◽  
Messenger Rna

An Electron-Microscope Study of the in vitro Transformation of Human Leucocytes

1967 ◽  
Vol 2 (3) ◽  
pp. 359-370
Author(s):  
J. A. CHAPMAN ◽  
M. W. ELVES ◽  
J. GOUGH
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Messenger Rna ◽  
Human Peripheral Blood ◽  
Limited Extent ◽  
Single Particles ◽  
Blast Cells ◽  
Protein Secreting

Electron-microscope studies of cultured small lymphocytes from human peripheral blood transforming into larger blastoid cells in the presence of phytohaemagglutinin (PHA) show that the transformed cell possesses the preliminary stages of development of a protein-synthesizing system. The transformed blastoid cell has abundant ribosomes, although, in contrast with in vivo protein-secreting cells, many of these occur as single particles with only a small proportion Linked in polysomal clusters. Endoplasmic reticulum membranes occur to a very limited extent and with a marked paucity of attached ribosomal particles; the few attached particles are usually located in groups. Some endoplasmic reticulum membranes revealed degenerative changes in otherwise normal cells. A moderately well-developed Golgi apparatus was a characteristic feature of the cells. Apart from the relatively low proportion of polysomes, in vitro PHA-transformed blastoid cells are identical in fine structure to in vivo blast cells (otherwise known as immunoblasts, haemocytoblasts, etc.) occurring in the immune response. It is suggested that messenger-RNA production in PHA-stimulated transformed cells may be reduced and that this could explain the limited number of polysomes and the restricted development of the endoplasmic reticulum.

scholarly journals Transient Cerebral Ischemia Activates Processing of xbp1 Messenger RNA Indicative of Endoplasmic Reticulum Stress

2003 ◽  
Vol 23 (4) ◽  
pp. 449-461 ◽  
Author(s):  
Wulf Paschen ◽  
Christoph Aufenberg ◽  
Svenja Hotop ◽  
Thorsten Mengesdorf
Keyword(s):  
Endoplasmic Reticulum ◽  
Cerebral Ischemia ◽  
Er Stress ◽  
Messenger Rna ◽  
Stress Proteins ◽  
Focal Cerebral Ischemia ◽  
Signal Transduction Pathway ◽  
Transient Cerebral Ischemia ◽  
Mrna Levels ◽  
Xbp1 Mrna

Cells respond to conditions associated with endoplasmic reticulum (ER) dysfunction with activation of the unfolded protein response, characterized by a shutdown of translation and induction of the expression of genes coding for ER stress proteins. The genetic response is based on IRE1-induced processing of xbp1 messenger RNA (mRNA), resulting in synthesis of new XBP1proc protein that functions as a potent transcription factor for ER stress genes. xbp1 processing in models of transient global and focal cerebral ischemia was studied. A marked increase in processed xbp1 mRNA levels during reperfusion was observed, most pronounced (about 35-fold) after 1-h occlusion of the right middle cerebral artery. The rise in processed xbp1 mRNA was not paralleled by a similar increase in XBP1proc protein levels because transient ischemia induces severe suppression of translation. As a result, mRNA levels of genes coding for ER stress proteins were only slightly increased, whereas mRNA levels of heat-shock protein 70 rose about 550-fold. Under conditions associated with ER dysfunction, cells require activation of the entire ER stress-induced signal transduction pathway, to cope with this severe form of stress. After transient cerebral ischemia, however, the block of translation may prevent synthesis of new XBP1proc protein and thus hinder recovery from ischemia-induced ER dysfunction.

scholarly journals Endoplasmic Reticulum Stress Is Involved in Baicalin Protection on Chondrocytes From Patients With Osteoarthritis

Dose-Response ◽  
2018 ◽  
Vol 16 (4) ◽  
pp. 155932581881063 ◽  
Author(s):  
Jiangang Cao ◽  
Yu Zhang ◽  
Tianyi Wang ◽  
Bo Li
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Cell Viability ◽  
Er Stress ◽  
Messenger Rna ◽  
Cell Counting ◽  
Protective Effects ◽  
Gene Expressions ◽  
Protein Levels

Osteoarthritis (OA) affects elderly population worldwide and endoplasmic reticulum (ER) stress is known to be positively correlated with OA development. Previous reports prove the cytoprotective effects of baicalin on chondrocytes, whereas the mechanisms are hardly reported. Hence, we aimed to investigate the links between OA, ER stress, and baicalin. Chondrocytes from patients with OA were subjected to H2O2 treatment with or without baicalin pretreatment, and cell viability was assessed via Cell Counting Kit-8. Messenger RNA (mRNA) amounts of apoptosis-related genes (Bax, Bcl-2, and Caspase-3), extracellular matrix (ECM)-related genes (Collange I, Collange II, Aggrecan, and Sox9) and ER stress hallmarks (binding immunoglobulin protein [BiP] C/EBP homologous protein [CHOP]) were evaluated via quantitative real-time PCR. Bax, Bcl-2, BiP, and CHOP protein levels were analyzed via Western blot. Baicalin suppressed the changes in cell viability and apoptosis-related gene expressions caused by H2O2. Reactive oxygen species and glutathione/oxidized glutathione assay showed that H2O2 enhanced oxidative stress. Baicalin suppressed H2O2-induced downregulation of mRNA expression of ECM-related genes. Moreover, baicalin reduced H2O2-stimulated increase in oxidative stress and the expression of ER stress hallmarks. Endoplasmic reticulum stress inducer abolished the protective activities, whereas ER stress inhibitor did not exhibit extra protective effects. Baicalin pretreatment protected patient-derived chondrocytes from H2O2 through ER stress inhibition.

scholarly journals WOUND HEALING AND COLLAGEN FORMATION

1964 ◽  
Vol 22 (2) ◽  
pp. 365-398 ◽  
Author(s):  
Russell Ross ◽  
Earl P. Benditt
Keyword(s):  
Endoplasmic Reticulum ◽  
Ascorbic Acid ◽  
Messenger Rna ◽  
Complete Disappearance ◽  
Extracellular Material ◽  
Material Characteristic ◽  
Collagen Formation ◽  
Hydroxyamino Acids ◽  
Curved Paths ◽  
Filamentous Material

The changes in scorbutic wounds following the administration of ascorbic acid have been investigated using the techniques of electron microscopy, histochemistry, and autoradioggraphy. Particular attention has been paid to the changes seen in the endoplasmic reticulum of the fibroblasts and to the identity of the extracellular filamentous material characteristic of scorbutic wounds. Seven-day-old wounds in scorbutic guinea pigs were examined prior to and from one to 72 hours following the administration of vitamin C. Fibroblasts from wounds of normal animals demonstrate a characteristic configuration of the ribosomes of the endoplasmic reticulum which is suggested to be analogous to polyribosomes described in cells synthesizing protein such as the reticulocyte. Tangential views of the membranes of the ergastoplasm show the ribosomes to be grouped in paired rows which take both straight and curved paths. This configuration is lost in scurvy and can be seen to begin to reappear as early as 4 hours after giving ascorbic acid. With increasing time, the morphology of the ribosomal aggregates approximates that seen in normal cells, so that by 24 hours their reorientation is complete. It is suggested that one of the disturbances in scurvy may relate to an alteration either in messenger RNA, in the ability of the ribosomes to relate to the messenger, or in the membranes of the ergastoplasm. In addition, the lack of formation of hydroxyamino acids necessary for completing collagen synthesis may be related to the architecture of the ribosomal aggregates. Extracellular collagen fibrils appear concomitant with the restoration of ribosomal and ergastoplasmic morphology as early as 12 hours after administration of ascorbic acid, with complete disappearance of the scorbutic extracellular material within 24 hours. Observations of this scorbutic material do not support the concept that it is a collagen precursor.

scholarly journals Messenger RNA targeting to endoplasmic reticulum stress signalling sites

Nature ◽  
2008 ◽  
Vol 457 (7230) ◽  
pp. 736-740 ◽  
Author(s):  
Tomás Aragón ◽  
Eelco van Anken ◽  
David Pincus ◽  
Iana M. Serafimova ◽  
Alexei V. Korennykh ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Messenger Rna ◽  
Rna Targeting ◽  
Stress Signalling

scholarly journals Direct association of messenger RNA labeled in the presence of fluoroorotate with membranes of the endoplasmic reticulum in rat liver.

1976 ◽  
Vol 70 (1) ◽  
pp. 47-58 ◽  
Author(s):  
J Cardelli ◽  
B Long ◽  
H C Pitot
Keyword(s):  
Endoplasmic Reticulum ◽  
Ribosomal Rna ◽  
Messenger Rna ◽  
Translational Regulation ◽  
Orotic Acid ◽  
Complete Removal ◽  
High Ionic Strength ◽  
Messenger Rnas ◽  
Direct Association ◽  
Pancreatic Rnase

Liver rough endoplasmic reticulum (RER) membranes were isolated from rats given [3H]orotic acid for 48 h (ribosomal RNA [rRNA] label) or for 3 h along with 5-fluoroorotate; this latter procedure permits the labeling of cytoplasmic messenger RNAs (mRNAs) in the absence of rRNA labeling. More than 50% of the labeled mRNA remained attached to membranes of the RER after complete removal of ribosomes with a buffer of high ionic strength in the presence of puromycin. Under similar conditions, membranes retained 40% of their polyadenylate as determined by a [3H]-polyuridylate hybridization assay. Treatment of mRNA-labeled endoplasmic reticulum membranes with pancreatic RNase indicates that the polyadenylate and possibly nonpolyadenylate-pyrimidine portions of the messenger are involved in the binding of mRNA to the membranes. The implication of these results in furthering our understanding of the mechanisms of the translational regulation of genetic expression is discussed.

scholarly journals ATTACHMENT OF RIBOSOMES TO MEMBRANES DURING POLYSOME FORMATION IN MOUSE SARCOMA 180 CELLS

1971 ◽  
Vol 49 (3) ◽  
pp. 683-691 ◽  
Author(s):  
Se Yong Lee ◽  
Velibor Krsmanovic ◽  
George Brawerman
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Messenger Rna ◽  
Ethylenediaminetetraacetic Acid ◽  
Sarcoma 180 ◽  
Intact Cells ◽  
Cell Lysates ◽  
Mouse Sarcoma ◽  
Rnase Treatment ◽  
Rapid Conversion

Addition of nutrients to starved mouse S-180 cells leads to rapid conversion of ribosomal monomers to polysomes. During this process, a portion of the ribosomes originally found in the 17,000 g (10 min centrifugation) supernatant of cell lysates becomes firmly attached to structures sedimenting at 500 g (5 min centrifugation). Electron microscopy of sections of the intact cells showed the change from randomly distributed ribosomal particles to clusters. Association with membranes also became evident. The material sedimenting at 500 g comprised nuclei enclosed in an extensive endoplasmic reticulum (ER) network. This fraction prepared from recovering cells showed numerous ribosome clusters associated with the ER network. The appearance of many of these clusters indicated that the ribosomal particles were not directly bound to the membranes. RNase treatment released about 40% of the attached ribosomes as monomers, and ethylenediaminetetraacetic acid released 60% as subunits. It is suggested that during polysome formation a portion of the ribosomes becomes attached to the membranes through the intermediary of messenger RNA.

The Role of Intracellular Membranes in Protein Processing

1981 ◽  
Vol 39 ◽  
pp. 514-515
Author(s):  
Dennis Shields ◽  
Thomas G. Warren ◽  
Sara E. Roth ◽  
Reza F. Green
Keyword(s):  
Endoplasmic Reticulum ◽  
Signal Peptide ◽  
Messenger Rna ◽  
Polypeptide Chain ◽  
Secretory Protein ◽  
Free Protein ◽  
Amino Terminal ◽  
Free Translation ◽  
Microsomal Membranes

Most polypeptides destined for secretion are synthesized on polyribosomes bound to the membrane of the endoplasmic reticulum (E.R.), in contrast, cytosolic proteins are made on free ribosomes. When the messenger RNA (mRNA) for a secretory protein is translated in a cell-free protein synthesizing system, the product is usually larger than the mature protein by about 3,000 daltons. Numerous studies have demonstrated that the higher molecular weight of the cell-free translation product can be attributed to an amino terminal extension of about 20-30 amino acids termed the “signal peptide”. This signal peptide is thought to mediate binding of ribosomes bearing the nascent polypeptide chain to the membrane of the endoplasmic reticulum. Upon interaction with the E.R., the polypeptide chain is translocated across the membrane usually resulting in proteolytic removal of the signal peptide and segregation of the “processed” polypeptide into the ER. cisternae. This series of reactions can be followed in vitro by supplementing the cell-free protein synthesizing system with heterologous microsomal membranes which have been stripped of their endogenous ribosomes.

2,4,6-Trichlorophenol Cytotoxicity Involves Oxidative Stress, Endoplasmic Reticulum Stress, and Apoptosis

2014 ◽  
Vol 33 (6) ◽  
pp. 532-541 ◽  
Author(s):  
Xiaoning Zhang ◽  
Xiaona Zhang ◽  
Zhidan Niu ◽  
Yongmei Qi ◽  
Dejun Huang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Messenger Rna ◽  
Nuclear Translocation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Α Subunit

This study aims to evaluate the cytotoxicity and potential mechanisms of 2,4,6-trichlorophenol (2,4,6-TCP) in mouse embryonic fibroblasts. Our results show that 2,4,6-TCP causes morphological changes and reduces cell viability. The overproduction of reactive oxygen species, the upregulation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX1) messenger RNA (mRNA) expressions, and the nuclear translocation of Nrf2 protein demonstrate that 2,4,6-TCP induces oxidative stress, and the Nrf2/HMOX1 pathway might be involved in 2,4,6-TCP-induced antioxidative response. Simultaneously, our data also demonstrate that 2,4,6-TCP upregulates the expressions of binding immunoglobulin protein, inositol-requiring enzyme/endonuclease 1α, and C/EBP homologous protein; stimulates α subunit of eukaryotic translation initiation factor 2 phosphorylation; and induces the splicing of Xbp1 mRNA, suggesting that endoplasmic reticulum (ER) stress is triggered. Moreover, 2,4,6-TCP alters the mitochondrial membrane potential and increases the apoptosis rate, the caspase 3 activity, and the Bax/Bcl-2 ratio, demonstrating that the mitochondrial pathway is involved in the 2,4,6-TCP-induced apoptosis. Thus, these results show that 2,4,6-TCP induces oxidative stress, ER stress, and apoptosis, which together contribute to its cytotoxicity in vitro.

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