scholarly journals NSUN2 introduces 5-methylcytosines in mammalian mitochondrial tRNAs

2019 ◽  
Author(s):  
Lindsey Van Haute ◽  
Song-Yi Lee ◽  
Beverly J. McCann ◽  
Christopher A. Powell ◽  
Dhiru Bansal ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Mitochondrial Gene ◽  
Proper Function ◽  
Mitochondrial Rna ◽  
Differentiated Cells ◽  
Pathogenic Variants ◽  
Cell Proliferation And Differentiation ◽  
Mammalian Mitochondria ◽  
Proliferation And Differentiation ◽  
The Matrix

AbstractMaintenance and expression of mitochondrial DNA is indispensable for proper function of the oxidative phosphorylation machinery. Post-transcriptional modification of mitochondrial RNA has emerged as one of the key regulatory steps of human mitochondrial gene expression. Mammalian NOP2/Sun RNA Methyltransferase Family Member 2 (NSUN2) has been characterised as an RNA methyltransferase that introduces 5-methylcytosine (m5C) in nuclear-encoded tRNAs, mRNAs, microRNA and noncoding RNAs. In these roles, NSUN2 has been associated with cell proliferation and differentiation. Pathogenic variants in NSUN2 have been linked with neurodevelopmental disorders. Here we employ spatially restricted proximity labelling and immunodetection to demonstrate that NSUN2 is imported into the matrix of mammalian mitochondria. Using three genetic models for NSUN2 inactivation – knockout mice, patient-derived fibroblasts and CRISPR/Cas9 knockout in human cells – we show that NSUN2 in necessary for the generation of m5C at positions 48, 49 and 50 of several mammalian mitochondrial tRNAs. Finally, we show that inactivation of NSUN2 does not have a profound effect on mitochondrial tRNA stability and oxidative phosphorylation in differentiated cells. We discuss the importance of the newly discovered function of NSUN2 in the context of human disease.

scholarly journals NSUN2 introduces 5-methylcytosines in mammalian mitochondrial tRNAs

2019 ◽  
Vol 47 (16) ◽  
pp. 8720-8733 ◽  
Author(s):  
Lindsey Van Haute ◽  
Song-Yi Lee ◽  
Beverly J McCann ◽  
Christopher A Powell ◽  
Dhiru Bansal ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Mitochondrial Gene ◽  
Proper Function ◽  
Human Mitochondrial Dna ◽  
Differentiated Cells ◽  
Pathogenic Variants ◽  
Cell Proliferation And Differentiation ◽  
Mammalian Mitochondria ◽  
Proliferation And Differentiation ◽  
The Matrix

Abstract Expression of human mitochondrial DNA is indispensable for proper function of the oxidative phosphorylation machinery. The mitochondrial genome encodes 22 tRNAs, 2 rRNAs and 11 mRNAs and their post-transcriptional modification constitutes one of the key regulatory steps during mitochondrial gene expression. Cytosine-5 methylation (m5C) has been detected in mitochondrial transcriptome, however its biogenesis has not been investigated in details. Mammalian NOP2/Sun RNA Methyltransferase Family Member 2 (NSUN2) has been characterized as an RNA methyltransferase introducing m5C in nuclear-encoded tRNAs, mRNAs and microRNAs and associated with cell proliferation and differentiation, with pathogenic variants in NSUN2 being linked to neurodevelopmental disorders. Here we employ spatially restricted proximity labelling and immunodetection to demonstrate that NSUN2 is imported into the matrix of mammalian mitochondria. Using three genetic models for NSUN2 inactivation—knockout mice, patient-derived fibroblasts and CRISPR/Cas9 knockout in human cells—we show that NSUN2 is necessary for the generation of m5C at positions 48, 49 and 50 of several mammalian mitochondrial tRNAs. Finally, we show that inactivation of NSUN2 does not have a profound effect on mitochondrial tRNA stability and oxidative phosphorylation in differentiated cells. We discuss the importance of the newly discovered function of NSUN2 in the context of human disease.

ANALYSIS OF PROTEOGLYCAN GENE EXPRESSION IN CONNECTIVE TISSUES BY SEMI-QUANTITATIVE RT-PCR

2001 ◽  
Vol 05 (02) ◽  
pp. 79-88
Author(s):  
K. Dobra ◽  
A. Hjerpe
Keyword(s):  
Rt Pcr ◽  
Connective Tissues ◽  
Surrounding Matrix ◽  
Cell Proliferation And Differentiation ◽  
Extracellular Matrix Components ◽  
Proliferation And Differentiation ◽  
The Matrix ◽  
Quantitative Changes ◽  
Regulatory Functions ◽  
Multiple Samples

Proteoglycans (PGs) are cell-membrane and extracellular matrix components with a wide variety of different functions. In the matrix, they are mainly of structural importance, although some of them have been ascribed specific regulatory functions, such as in the assembly of collagen fibers. PGs on the cell surface act as essential modulators of specific ligand-binding reactions, involving interactions between adjacent cells and between cells and surrounding matrix. Through these interactions they participate in different processes, including cell proliferation and differentiation. Qualitative and quantitative changes in PG expression can therefore be associated with various physiological and pathological conditions. We have optimized the conditions for semi-quantitative evaluation of proteoglycan expression by RT-PCR reaction, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as reference gene. The relative fluorescence of analyte to reference amplimers can — within certain limits — be used to estimate the amount of target RNA and allows direct comparison of multiple samples. The profile of PG expression obtained in this way can be used to extend our current understanding of the possible functions that can be associated with these complex molecules.

The post-transcriptional life of mammalian mitochondrial RNA

2012 ◽  
Vol 444 (3) ◽  
pp. 357-373 ◽  
Author(s):  
Joanna Rorbach ◽  
Michal Minczuk
Keyword(s):  
Messenger Rna ◽  
Mitochondrial Gene ◽  
Rna Stability ◽  
Stability Control ◽  
Mitochondrial Rna ◽  
Mammalian Mitochondria ◽  
Mitochondrial Ribosome ◽  
Rna Maturation ◽  
Rna Polyadenylation

Mammalian mitochondria contain their own genome that encodes mRNAs for thirteen essential subunits of the complexes performing oxidative phosporylation as well as the RNA components (two rRNAs and 22 tRNAs) needed for their translation in mitochondria. All RNA species are produced from single polycistronic precursor RNAs, yet the relative concentrations of various RNAs differ significantly. This underscores the essential role of post-transcriptional mechanisms that control the maturation, stability and translation of mitochondrial RNAs. The present review provides a detailed summary on the role of RNA maturation in the regulation of mitochondrial gene expression, focusing mainly on messenger RNA polyadenylation and stability control. Furthermore, the role of mitochondrial ribosomal RNA stability, processing and modifications in the biogenesis of the mitochondrial ribosome is discussed.

004.Control of skeletal muscle cell proliferation and differentiation

2005 ◽  
Vol 17 (9) ◽  
pp. 63
Author(s):  
M. Grounds
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Multinucleated Cells ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
The Matrix ◽  
Key Issues

Skeletal muscle is formed by mononucleated precursor cells (myoblasts) that cease cell proliferation to start differentiation; this results in fusion between the myoblasts to form multinucleated cells (myotubes) that continue to differentiate (and fuse with more muscle cells) and mature into myofibres. Myogenesis has been widely used as a model to study in vitro factors controlling cell proliferation and differentiation. Condition in vitro may not reflect what happens in the more complex in vivo environment. Some of the key issues are what activates quiescent myoblasts in mature skeletal muscle in vivo, and what controls the switch between proliferation and differentiation? The role of the matrix, and molecules such as MyoD, p53, NFAT and IGF-1 will be considered.

scholarly journals Insulin increases the density of potassium channels in white adipocytes: possible role in adipogenesis

2002 ◽  
Vol 174 (2) ◽  
pp. 299-307 ◽  
Author(s):  
MP Ramirez-Ponce ◽  
JC Mateos ◽  
JA Bellido
Keyword(s):  
Potassium Channels ◽  
Normal Growth ◽  
Potassium Currents ◽  
High Concentration ◽  
Differentiated Cells ◽  
White Adipocytes ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Inhibition Of Differentiation

We studied the potassium currents in white adipocytes obtained by culturing preadipocytes from rat epididymal tissue, both with insulin (WA(i)) and without insulin (WA(o)), in order to test the role of insulin in the development of voltage-gated potassium channels (K(v)) during adipogenesis. Occasionally, very small potassium currents (I(K,V)) were present in preadipocytes; however these currents were measured in all differentiated cells (adipocytes). WA(i) exhibited greater macroscopic potassium currents than WA(o) with no apparent differences in kinetics or voltage dependence. The current density (pA/ micro m(2)) calculated in WA(i) was higher than in WA(o). Currents were blocked by millimolar concentrations of tetrethylamonium (TEA). The effect of insulin on adipogenesis, both with and without TEA, was analysed. Four days without insulin and three days with insulin were necessary to increase the total number of cells in culture by 2.5-fold. Insulin increased the number of differentiated cells by 73.5%. Cell proliferation and differentiation were inhibited by TEA. Proliferation was affected only by high concentration of TEA. Inhibition of differentiation was dose dependent, with the concentration necessary for half-block similar to the IC(50) values to block potassium channels. These results suggest that insulin increases the density of K(v) and that these channels may be necessary for the normal growth of white adipocytes in culture.

scholarly journals RNA Granules in the Mitochondria and Their Organization under Mitochondrial Stresses

2021 ◽  
Vol 22 (17) ◽  
pp. 9502
Author(s):  
Vanessa Joanne Xavier ◽  
Jean-Claude Martinou
Keyword(s):  
Rna Processing ◽  
Protein Complexes ◽  
Mitochondrial Gene ◽  
Mitochondrial Fission ◽  
Mitochondrial Rna ◽  
Rna Regulation ◽  
Rna Granules ◽  
Chain Complexes ◽  
The Matrix ◽  
Rna Quality Control

The human mitochondrial genome (mtDNA) regulates its transcription products in specialised and distinct ways as compared to nuclear transcription. Thanks to its mtDNA mitochondria possess their own set of tRNAs, rRNAs and mRNAs that encode a subset of the protein subunits of the electron transport chain complexes. The RNA regulation within mitochondria is organised within specialised, membraneless, compartments of RNA-protein complexes, called the Mitochondrial RNA Granules (MRGs). MRGs were first identified to contain nascent mRNA, complexed with many proteins involved in RNA processing and maturation and ribosome assembly. Most recently, double-stranded RNA (dsRNA) species, a hybrid of the two complementary mRNA strands, were found to form granules in the matrix of mitochondria. These RNA granules are therefore components of the mitochondrial post-transcriptional pathway and as such play an essential role in mitochondrial gene expression. Mitochondrial dysfunctions in the form of, for example, RNA processing or RNA quality control defects, or inhibition of mitochondrial fission, can cause the loss or the aberrant accumulation of these RNA granules. These findings underline the important link between mitochondrial maintenance and the efficient expression of its genome.

Role of melatonin in regulating neurogenesis: Implications for the neurodegenerative pathology and analogous therapeutics for Alzheimer’s disease

2020 ◽  
Vol 3 (2) ◽  
pp. 216-242 ◽  
Author(s):  
Mayuri Shukla ◽  
Areechun Sotthibundhu ◽  
Piyarat Govitrapong
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Adult Neurogenesis ◽  
Adult Brain ◽  
Therapeutic Approaches ◽  
Therapeutic Implications ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Progenitor Cell Proliferation

The revelation of adult brain exhibiting neurogenesis has established that the brain possesses great plasticity and that neurons could be spawned in the neurogenic zones where hippocampal adult neurogenesis attributes to learning and memory processes. With strong implications in brain functional homeostasis, aging and cognition, various aspects of adult neurogenesis reveal exuberant mechanistic associations thereby further aiding in facilitating the therapeutic approaches regarding the development of neurodegenerative processes in Alzheimer’s Disease (AD). Impaired neurogenesis has been significantly evident in AD with compromised hippocampal function and cognitive deficits. Melatonin the pineal indolamine augments neurogenesis and has been linked to AD development as its levels are compromised with disease progression. Here, in this review, we discuss and appraise the mechanisms via which melatonin regulates neurogenesis in pathophysiological conditions which would unravel the molecular basis in such conditions and its role in endogenous brain repair. Also, its components as key regulators of neural stem and progenitor cell proliferation and differentiation in the embryonic and adult brain would aid in accentuating the therapeutic implications of this indoleamine in line of prevention and treatment of AD.   

Icariin Stimulates hFOB 1.19 Osteoblast Proliferation and Differentiation via OPG/RANKL Mediated by the Estrogen Receptor

2020 ◽  
Vol 22 (1) ◽  
pp. 168-175 ◽  
Author(s):  
Lin-Jun Sun ◽  
Chong Li ◽  
Xiang-hao Wen ◽  
Lu Guo ◽  
Zi-Fen Guo ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Estrogen Receptor ◽  
Protein Expression ◽  
Chinese Herb ◽  
Human Osteoblast ◽  
Osteoblast Cells ◽  
Expression Ratio ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Mrna And Protein Expression

Background:: Icariin (ICA), one of the main effective components isolated from the traditional Chinese herb Epimedium brevicornu Maxim., has been reported to possess extensive pharmacological actions, including enhanced sexual function, immune regulation, anti-inflammation, and antiosteoporosis. Methods:: Our study was designed to investigate the effect of ICA on cell proliferation and differentiation and the molecular mechanism of OPG/RANKL mediated by the Estrogen Receptor (ER) in hFOB1.19 human osteoblast cells. Results:: The experimental results show that ICA can stimulate cell proliferation and increase the activity of Alkaline Phosphatase (ALP), Osteocalcin (BGP) and I Collagen (Col I) and a number of calcified nodules. Furthermore, the mRNA and protein expression of OPG and RANKL and the OPG/ RANKL mRNA and protein expression ratios were upregulated by ICA. The above-mentioned results indicated that the optimal concentration of ICA for stimulating osteogenesis was 50ng/mL. Subsequent mechanistic studies comparing 50ng/mL ICA with an estrogen receptor antagonist demonstrated that the effect of the upregulated expression is connected with the estrogen receptor. In conclusion, ICA can regulate bone formation by promoting cell proliferation and differentiation and upregulating the OPG/RANKL expression ratio by the ER in hFOB1.19 human osteoblast cells.

MicroRNA Determines the Fate of Intestinal Epithelial Cell Differentiation and Regulates Intestinal Diseases

2019 ◽  
Vol 20 (7) ◽  
pp. 666-673 ◽  
Author(s):  
Sujuan Ding ◽  
Gang Liu ◽  
Hongmei Jiang ◽  
Jun Fang
Keyword(s):  
Target Genes ◽  
Gastrointestinal Disease ◽  
Intestinal Barrier ◽  
Vital Role ◽  
Intestinal Barrier Function ◽  
Intestinal Epithelial ◽  
Intestinal Function ◽  
Cell Fates ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation

The rapid self-renewal of intestinal epithelial cells enhances intestinal function, promotes the nutritional needs of animals and strengthens intestinal barrier function to resist the invasion of foreign pathogens. MicroRNAs (miRNAs) are a class of short-chain, non-coding RNAs that regulate stem cell proliferation and differentiation by down-regulating hundreds of conserved target genes after transcription via seed pairing to the 3' untranslated regions. Numerous studies have shown that miRNAs can improve intestinal function by participating in the proliferation and differentiation of different cell populations in the intestine. In addition, miRNAs also contribute to disease regulation and therefore not only play a vital role in the gastrointestinal disease management but also act as blood or tissue biomarkers of disease. As changes to the levels of miRNAs can change cell fates, miRNA-mediated gene regulation can be used to update therapeutic strategies and approaches to disease treatment.

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