scholarly journals Microtubule-based Transport is Essential to Distribute RNA and Nascent Protein in Skeletal Muscle

2021 ◽  
Author(s):  
Lance T. Denes ◽  
Chase P. Kelley ◽  
Eric T. Wang
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Nuclear Envelope ◽  
Muscle Development ◽  
Rna Localization ◽  
Microtubule Network ◽  
Basic Principles ◽  
General Role ◽  
Rna Molecules ◽  
Differentiated Cells

SUMMARYWhile the importance of RNA localization in highly differentiated cells is well appreciated, basic principles of RNA localization in skeletal muscle remain poorly characterized. Here, we develop a method to detect single RNA molecules and quantify localization patterns in skeletal myofibers, and we uncover a critical and general role for directed transport of RNPs in muscle. We find that RNAs are localized and translated along cytoskeletal filaments, and we identify the Z-disk as a biological hub for RNA localization and protein synthesis. We show that muscle development triggers complete reliance on the lattice-like microtubule network to transport RNAs and that disruption of microtubules leads to striking accumulation of RNPs and nascent protein around myonuclei. Our observations suggest that active transport may be globally required to distribute RNAs in highly differentiated cells and reveal fundamental mechanisms relevant to myopathies caused by perturbations to RNPs, microtubules, and the nuclear envelope.Abstract Figure

scholarly journals Microtubule-based transport is essential to distribute RNA and nascent protein in skeletal muscle

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lance T. Denes ◽  
Chase P. Kelley ◽  
Eric T. Wang
Keyword(s):  
Skeletal Muscle ◽  
Single Molecule ◽  
Protein Function ◽  
Muscle Development ◽  
Critical Role ◽  
Rna Localization ◽  
Microtubule Network ◽  
Basic Principles ◽  
Directed Transport ◽  
Differentiated Cells

AbstractWhile the importance of RNA localization in highly differentiated cells is well appreciated, basic principles of RNA localization in skeletal muscle remain poorly characterized. Here, we develop a method to detect and quantify single molecule RNA localization patterns in skeletal myofibers, and uncover a critical role for directed transport of RNPs in muscle. We find that RNAs localize and are translated along sarcomere Z-disks, dispersing tens of microns from progenitor nuclei, regardless of encoded protein function. We find that directed transport along the lattice-like microtubule network of myofibers becomes essential to achieve this localization pattern as muscle development progresses; disruption of this network leads to extreme accumulation of RNPs and nascent protein around myonuclei. Our observations suggest that global active RNP transport may be required to distribute RNAs in highly differentiated cells and reveal fundamental mechanisms of gene regulation, with consequences for myopathies caused by perturbations to RNPs or microtubules.

scholarly journals LMNA Mutations G232E and R482L Cause Dysregulation of Skeletal Muscle Differentiation, Bioenergetics, and Metabolic Gene Expression Profile

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1057
Author(s):  
Elena V. Ignatieva ◽  
Oksana A. Ivanova ◽  
Margarita Y. Komarova ◽  
Natalia V. Khromova ◽  
Dmitrii E. Polev ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Neuromuscular Disorders ◽  
Control Cell ◽  
Muscle Differentiation ◽  
Mitochondrial Uncoupling ◽  
Partial Lipodystrophy ◽  
Differentiated Cells ◽  
Wide Range

Laminopathies are a family of monogenic multi-system diseases resulting from mutations in the LMNA gene which include a wide range of neuromuscular disorders. Although lamins are expressed in most types of differentiated cells, LMNA mutations selectively affect only specific tissues by mechanisms that remain largely unknown. We have employed the combination of functional in vitro experiments and transcriptome analysis in order to determine how two LMNA mutations associated with different phenotypes affect skeletal muscle development and metabolism. We used a muscle differentiation model based on C2C12 mouse myoblasts genetically modified with lentivirus constructs bearing wild-type human LMNA (WT-LMNA) or R482L-LMNA/G232E-LMNA mutations, linked to familial partial lipodystrophy of the Dunnigan type and muscular dystrophy phenotype accordingly. We have shown that both G232E/R482L-LMNA mutations cause dysregulation in coordination of pathways that control cell cycle dynamics and muscle differentiation. We have also found that R482/G232E-LMNA mutations induce mitochondrial uncoupling and a decrease in glycolytic activity in differentiated myotubes. Both types of alterations may contribute to mutation-induced muscle tissue pathology.

Ultra-Rapid Freezing of Isolated Skeletal Muscle Fibers

1977 ◽  
Vol 35 ◽  
pp. 576-577
Author(s):  
Joachim R. Sommer ◽  
Nancy R. Wallace
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Granular Material ◽  
Nuclear Envelope ◽  
Intracellular Calcium ◽  
Ruthenium Red ◽  
Threshold Concentration ◽  
Rapid Freezing ◽  
Frog Skeletal Muscle ◽  
Electrical Isolation

After Howell (1) had shown that ruthenium red treatment of fixed frog skeletal muscle caused collapse of the intermediate cisternae of the sarcoplasmic reticulum (SR), forming a pentalaminate structure by obi iterating the SR lumen, we demonstrated that the phenomenon involves the entire SR including the nuclear envelope and that it also occurs after treatment with other cations, including calcium (2,3,4).From these observations we have formulated a hypothesis which states that intracellular calcium taken up by the SR at the end of contraction causes the M rete to collapse at a certain threshold concentration as the first step in a subsequent centrifugal zippering of the free SR toward the junctional SR (JSR). This would cause a) bulk transport of SR contents, such as calcium and granular material (4) into the JSR and, b) electrical isolation of the free SR from the JSR.

Alterations in Ultrastructure of Skeletal Muscle From Newborn Guinea Pigs Following in Utero Exposure to Ethanol

1985 ◽  
Vol 43 ◽  
pp. 686-687
Author(s):  
C. Uphoff ◽  
C. Nyquist-Battie ◽  
T.B. Cole
Keyword(s):  
Skeletal Muscle ◽  
Guinea Pigs ◽  
Muscle Development ◽  
In Utero ◽  
Ethanol Exposure ◽  
Prenatally Exposed ◽  
Chronic Alcoholic ◽  
Test Kit ◽  
Food And Water Intake ◽  
Post Intubation

Ultrastructural alterations of skeletal muscle have been observed in adult chronic alcoholic patients. However, no such study has been performed on individuals prenatally exposed to ethanol. In order to determine if ethanol exposure in utero in the latter stages of muscle development was deleterious, skeletal muscle was obtained from newborn guinea pigs treated in the following manner. Six Hartly strain pregnant guinea pigs were randomly assigned to either the ethanol or the pair-intubated groups. Twice daily the 3 ethanol-treated animals were intubated with Ensure (Ross Laboratories) liquid diet containing 30% ethanol (6g/Kg pre-pregnant body weight per day) from day 35 of gestation until parturition at day 70±1 day. Serum ethanol levels were determined at 1 hour post-intubation by the Sigma alcohol test kit. For pair-intubation the Ensure diet contained sucrose substituted isocalorically for ethanol. Both food and water intake were monitored.

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