Muscle-specific expression of the troponin I gene requires interactions between helix-loop-helix muscle regulatory factors and ubiquitous transcription factors

1991 ◽  
Vol 11 (1) ◽  
pp. 267-280 ◽  
Author(s):  
H Lin ◽  
K E Yutzey ◽  
S F Konieczny
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Troponin I ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Specific Expression ◽  
Enhancer Activity ◽  
Regulatory Factors ◽  
Helix Loop Helix ◽  
Muscle Regulatory Factors

The quail fast skeletal troponin I (TnI) gene is a member of the contractile protein gene set and is expressed exclusively in differentiated skeletal muscle cells. TnI gene transcription is controlled by an internal regulatory element (IRE), located within the first intron, that functions as a muscle-specific enhancer. Recent studies have shown that the TnI IRE may interact directly with the muscle regulatory factors MyoD, myogenin, and Myf-5 to produce a muscle-specific expression pattern, since these factors trans-activate cotransfected TnI gene constructs in C3H10T1/2 fibroblasts. In this study, we have examined the protein-IRE interactions that are responsible for transcriptionally activating the TnI gene during skeletal muscle development. We demonstrate that the helix-loop-helix muscle regulatory factors MyoD, myogenin, Myf-5, and MRF4, when complexed with the immunoglobulin enhancer-binding protein E12, interact with identical nucleotides within a muscle regulatory factor-binding site (MRF site) located in the TnI IRE. The nuclear proteins that bind to the MRF site are restricted to skeletal muscle cells, since protein extracts from HeLa, L, and C3H10T1/2 fibroblasts do not contain similar binding activities. Importantly, the TnI MRF site alone is not sufficient to elicit the full enhancer activity associated with the IRE. Instead, two additional regions (site I and site II) are required. The proteins that interact with site I and site II are expressed in both muscle and nonmuscle cell types and by themselves are ineffective in activating TnI gene expression. However, when the MRF site is positioned upstream or downstream of site I and site II, full enhancer activity is restored. We conclude that helix-loop-helix muscle regulatory factors must interact with ubiquitously expressed proteins to generate the active TnI transcription complex that is present in differentiated muscle fibers.

scholarly journals Muscle-specific expression of the troponin I gene requires interactions between helix-loop-helix muscle regulatory factors and ubiquitous transcription factors.

1991 ◽  
Vol 11 (1) ◽  
pp. 267-280 ◽  
Author(s):  
H Lin ◽  
K E Yutzey ◽  
S F Konieczny
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Troponin I ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Specific Expression ◽  
Enhancer Activity ◽  
Regulatory Factors ◽  
Helix Loop Helix ◽  
Muscle Regulatory Factors

The quail fast skeletal troponin I (TnI) gene is a member of the contractile protein gene set and is expressed exclusively in differentiated skeletal muscle cells. TnI gene transcription is controlled by an internal regulatory element (IRE), located within the first intron, that functions as a muscle-specific enhancer. Recent studies have shown that the TnI IRE may interact directly with the muscle regulatory factors MyoD, myogenin, and Myf-5 to produce a muscle-specific expression pattern, since these factors trans-activate cotransfected TnI gene constructs in C3H10T1/2 fibroblasts. In this study, we have examined the protein-IRE interactions that are responsible for transcriptionally activating the TnI gene during skeletal muscle development. We demonstrate that the helix-loop-helix muscle regulatory factors MyoD, myogenin, Myf-5, and MRF4, when complexed with the immunoglobulin enhancer-binding protein E12, interact with identical nucleotides within a muscle regulatory factor-binding site (MRF site) located in the TnI IRE. The nuclear proteins that bind to the MRF site are restricted to skeletal muscle cells, since protein extracts from HeLa, L, and C3H10T1/2 fibroblasts do not contain similar binding activities. Importantly, the TnI MRF site alone is not sufficient to elicit the full enhancer activity associated with the IRE. Instead, two additional regions (site I and site II) are required. The proteins that interact with site I and site II are expressed in both muscle and nonmuscle cell types and by themselves are ineffective in activating TnI gene expression. However, when the MRF site is positioned upstream or downstream of site I and site II, full enhancer activity is restored. We conclude that helix-loop-helix muscle regulatory factors must interact with ubiquitously expressed proteins to generate the active TnI transcription complex that is present in differentiated muscle fibers.

scholarly journals GATA elements control repression of cardiac troponin I promoter activity in skeletal muscle cells

2007 ◽  
Vol 8 (1) ◽  
pp. 78 ◽  
Author(s):  
Raffaella Di Lisi ◽  
Anne Picard ◽  
Simonetta Ausoni ◽  
Stefano Schiaffino
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Troponin ◽  
Promoter Activity ◽  
Troponin I ◽  
Muscle Cells ◽  
Cardiac Troponin I ◽  
Skeletal Muscle Cells

scholarly journals Expression Analysis of Irisin During Different Differentiation Stages of Skeletal Muscle Cells

2021 ◽  
Author(s):  
Yi Yan ◽  
Ding Yang ◽  
Pei Wen ◽  
Yilei Li ◽  
Yufang Ge ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Developmental Stages ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
Skeletal Muscle Cells ◽  
Growth Stages ◽  
Glucose And Lipid Metabolism ◽  
Muscle Tissues ◽  
Sexually Mature

Abstract Background: As a newly discovered muscle factor secreted by skeletal muscle cells, irisin is a polypeptide fragment formed after hydrolysis by fibronectin type Ⅲ domain-containing protein 5 (FNDC5). Previous studies have shown that irisin has biological functions that promote beigeing of WAT, regulate glucose and lipid metabolism. However, the functions of irisin in muscle development and muscle fat metabolism remain unknown.Results: In order to study the expression of irisin in different growth stages of skeletal muscle, this study used SPF mice as experimental subjects to select skeletal muscle cells and muscle tissues of different developmental stages of mice. The expression of irisin precursor FNDC5 in different stages of cells and tissues was detected by western blotting and real-time fluorescent quantitative PCR, and the expression of FNDC5 in cells was detected by immunofluorescence. The results showed that FNDC5 was expressed in all stages of tissues and cells, but the expression was different at different stages. FNDC5 protein has the highest expression in muscle of sexually mature mice, followed by elderly mice and adolescent mice, and low expression in pups. Secondly, FNDC5 protein is mainly expressed in the cytoplasm and highest in muscle fibers. The myotubes were the second, and the lowest in C2C12 cells. Conclusions: This experiment can provide a theoretical basis for the subsequent study of irisin in skeletal muscle, and lay the foundation for targeted therapy of related diseases.

Developmental regulation of the mouse IGF-I exon 1 promoter region by calcineurin activation of NFAT in skeletal muscle

2007 ◽  
Vol 292 (5) ◽  
pp. C1887-C1894 ◽  
Author(s):  
Christina M. Alfieri ◽  
Heather J. Evans-Anderson ◽  
Katherine E. Yutzey
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathways ◽  
Muscle Development ◽  
Developmental Regulation ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Conserved Regions ◽  
Igf I ◽  
Exon 1 ◽  
I Gene

Skeletal muscle development and growth are regulated through multiple signaling pathways that include insulin-like growth factor I (IGF-I) and calcineurin activation of nuclear factor of activated T cell (NFAT) transcription factors. The developmental regulation and molecular mechanisms that control IGF-I gene expression in murine embryos and in differentiating C2C12 skeletal myocytes were examined. IGF-I is expressed in developing skeletal muscle, and its embryonic expression is significantly reduced in embryos lacking both NFATc3 and NFATc4. During development, the IGF-I exon 1 promoter is active in multiple organ systems, including skeletal muscle, whereas the alternative exon 2 promoter is expressed predominantly in the liver. The IGF-I exon 1 promoter flanking sequence includes two highly conserved regions that contain NFAT consensus binding sequences. One of these conserved regions contains a calcineurin/NFAT-responsive regulatory region that is preferentially activated by NFATc3 in C2C12 skeletal muscle cells and NIH3T3 fibroblasts. This NFAT-responsive region contains three clustered NFAT consensus binding sequences, and mutagenesis experiments demonstrated the requirement for two of these in calcineurin or NFATc3 responsiveness. Chromatin immunoprecipitation analyses demonstrated that endogenous IGF-I genomic sequences containing these conserved NFAT binding sequences interact preferentially with NFATc3 in C2C12 cells. Together, these experiments demonstrated that a NFAT-rich regulatory element in the IGF-I exon 1 promoter flanking region is responsive to calcineurin signaling and NFAT activation in skeletal muscle cells. The identification of a calcineurin/NFAT-responsive element in the IGF-I gene represents a potential mechanism of intersection of these signaling pathways in the control of muscle development and homeostasis.

scholarly journals Differentiation capacity of native pituitary folliculostellate cells and brain astrocytes

2012 ◽  
Vol 213 (3) ◽  
pp. 231-237 ◽  
Author(s):  
Marumi Osuna ◽  
Yokiko Sonobe ◽  
Eisuke Itakura ◽  
Sukumar Devnath ◽  
Takako Kato ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Pituitary Gland ◽  
Cell Activity ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Transgenic Rat ◽  
Specific Expression ◽  
Differentiation Potential ◽  
Differentiation Capacity

Pituitary folliculostellate (FS) cells are characterized by producing S100B protein, as do brain astrocytes. FS cells have some functions in the pituitary gland, i.e. scavenger functions, sustentacular cell activity through cytokines, and intercellular communication through gap junctions. However, the biological significances of FS cells, especially their differentiation capacities in the anterior pituitary gland, are still under discussion. To understand FS cells with new approaches, we generated a transgenic rat expressing GFP under S100b gene promoter, which regulates tissue-specific expression of S100b gene. Using the transgenic rat, we succeeded in inducing skeletal muscle cells from FS cells by culturing it in serum-free medium containing B-27 supplement, thyroid hormone (tri-iodothyronine), epidermal growth factor, and basic fibroblast growth factor. In this study, we also succeeded in inducing skeletal muscle cells from primary cultured astrocytes and astrocyte cell line, C6 cells. Hence, we concluded that pituitary FS cells have wide differentiation potential and have similar characteristics to astrocytes, which not only support cell activity but also support differentiation capacity.

scholarly journals Muscle-specific activity of the skeletal troponin I promoter requires interaction between upstream regulatory sequences and elements contained within the first transcribed exon.

1990 ◽  
Vol 10 (7) ◽  
pp. 3468-3482 ◽  
Author(s):  
W Nikovits ◽  
J H Mar ◽  
C P Ordahl
Keyword(s):  
Skeletal Muscle ◽  
Transcription Initiation ◽  
Troponin I ◽  
Specific Activity ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Deletion Analysis ◽  
Regulatory Sequences ◽  
Mrna Levels ◽  
Cat Gene

Expression of the skeletal troponin I (sTnI) gene is regulated transcriptionally in a muscle-specific fashion. We show here that the region of the sTnI gene between -160 and +61 (relative to the transcription initiation site) is able to direct expression of the bacterial chloramphenicol acetyltransferase (CAT) gene is muscle cultures at a level approximately 100 times higher than in fibroblast cultures. RNA analysis demonstrated that transcription of the CAT gene was initiated at the same site as transcription of the endogenous sTnI gene and that CAT activity levels were approximately proportional to CAT mRNA levels. Deletion analysis demonstrated that the region between nucleotides -160 and -40 contained sequences essential for full promoter activity. Surprisingly, 3' deletion analysis indicated that the first exon (-6 to +61) of the sTnI gene was also required for full activity of the sTnI promoter in skeletal muscle cells. Chimeric promoter experiments, in which segments of the sTnI and the herpes simplex virus thymidine kinase promoter were interchanged, indicated that reconstitution of a muscle-specific promoter required inclusion of both the upstream and exon I regions of the sTnI gene. Exon I, and the region immediately upstream, showed DNase protection over sequence motifs related to those found in other genes, including the tar region of human immunodeficiency virus type 1. These results demonstrate that expression of the sTnI promoter in embryonic skeletal muscle cells requires complex interaction between two separate promoter regions, one of which resides within the first 61 transcribed nucleotides of the gene.

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