scholarly journals The β1 Cytoplasmic Domain Regulates the Laminin-binding Specificity of the α7X1 Integrin

2003 ◽  
Vol 14 (9) ◽  
pp. 3507-3518 ◽  
Author(s):  
Ming-Guang Yeh ◽  
Barry L. Ziober ◽  
Baomei Liu ◽  
Galina Lipkina ◽  
Ioannis S. Vizirianakis ◽  
...  
Keyword(s):  
Muscle Development ◽  
Splice Variants ◽  
Myogenic Differentiation ◽  
Cytoplasmic Domain ◽  
Developmentally Regulated ◽  
Relative Level ◽  
Affinity Modulation ◽  
Strong Adhesion ◽  
Alternatively Spliced ◽  
Functional Regulation

During muscle development, the laminin-specific α7 integrin is alternatively spliced in the putative ligand-binding domain to yield either the α7X1 or the α7X2 variant. The relative level of α7X1 and α7X2 is developmentally regulated. Similarly, the partner β1 integrin cytoplasmic domain is converted from the β1A to the β1D splice variant. To determine whether β1D modulates the activity of the α7 receptor, cells were transfected with α7X1 and β1D cDNA. α7X1 coupled with β1A failed to adhere to laminin-1, whereas cotransfectants expressing α7X1 and β1D showed strong adhesion. Interestingly, α7X1 complexed with β1A and β1D displayed the same level of poor adhesion to laminin-2/4 or strong adhesion to laminin-10/11. These findings indicate that α7 function is regulated not only by X1/X2 in its extracellular domain but also by β1 cytoplasmic splice variants. It is likely that expression of β1D alters α7X1 binding to laminin isoforms by a process related to ligand affinity modulation. Functional regulation of α7β1 by developmentally regulated splicing events may be important during myogenic differentiation and repair because the integrin mediates adhesion, motility, and cell survival.

Expression of alpha 7 integrin cytoplasmic domains during skeletal muscle development: alternate forms, conformational change, and homologies with serine/threonine kinases and tyrosine phosphatases

1993 ◽  
Vol 106 (4) ◽  
pp. 1139-1152 ◽  
Author(s):  
W.K. Song ◽  
W. Wang ◽  
H. Sato ◽  
D.A. Bielser ◽  
S.J. Kaufman
Keyword(s):  
Skeletal Muscle ◽  
Untranslated Region ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Cytoplasmic Domain ◽  
Cytoplasmic Domains ◽  
Coding Region ◽  
Common Coding ◽  
Alternate Forms ◽  
Alpha 7

We recently reported the cloning and sequencing of the alpha 7 integrin chain and its regulated expression during the development of skeletal muscle (Song et al. (1992) J. Cell Biol. 117, 643–657). The alpha 7 chain is expressed during the development of the myogenic lineage and on adult muscle fibers and this suggests that it participates in multiple and diverse functions at different times during muscle development. One interesting portion of this isoform is its cytoplasmic domain; comprised of 77 amino acids it is the largest in the alpha chains thus reported. In these experiments we begin to study the potential functions of the alpha 7 cytoplasmic domain by analyzing homologies between the rat and human sequences, by immunologic studies using an anti-cytoplasmic domain antiserum, and by identifying two alternate forms. In keeping with the nomenclature used to describe the alpha 3 and alpha 6 alternate cytoplasmic domains, we refer to the originally reported species as alpha 7B and the two additional forms as alpha 7A and alpha 7C. These three cytoplasmic domains likely arise as a consequence of alternate splicing. A splice site at the junctions of the transmembrane and cytoplasmic domains is used to generate the alpha 3, alpha 6 and alpha 7 A and B forms. The alpha 7A form RNA contains an additional 113 nucleotides compared to the B form, and a common coding region in the A and B form RNAs is used in alternate reading frames. Part of the coding region of alpha 7B appears to be used as the 3′-untranslated region of the alpha 7A form. The alpha 7C mRNA is 595 nucleotides smaller than the alpha 7B RNA and part of the 3′-untranslated region of the alpha 7B isoform is used as coding sequence in alpha 7C. There is developmental specificity in expression of these alternate mRNAs: alpha 7A and alpha 7C transcripts are found upon terminal myogenic differentiation whereas alpha 7B is present earlier in replicating cells and diminishes upon differentiation. We suggest this selective expression of the alpha 7 cytoplasmic domains underlies the diversity in function of the alpha 7 beta 1 integrin at different stages of muscle development. Immunochemical analyses indicate that the alpha 7B cytoplasmic domain undergoes a change in conformation in response to binding laminin or upon crosslinking initiated with antibody reactive with the integrin extracellular domain. Crosslinking also promotes association of the integrin with the cell cytoskeleton.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Developmentally regulated tcf7l2 splice variants mediate transcriptional repressor functions during eye formation

2019 ◽  
Author(s):  
Rodrigo M. Young ◽  
Kenneth B. Ewan ◽  
Veronica P. Ferrer ◽  
Miguel L. Allende ◽  
Jasminka Godovac-Zimmermann ◽  
...  
Keyword(s):  
Wnt Pathway ◽  
Splice Variants ◽  
Gene Promoters ◽  
Developmentally Regulated ◽  
Alternatively Spliced ◽  
Reporter Assays ◽  
Transcriptional Output ◽  
Biological Outcomes ◽  
Eye Formation

AbstractTcf7l2 mediates Wnt/β-Catenin signalling during development and is implicated in cancer and type-2 diabetes. The mechanisms by which Tcf7l2 and Wnt/β-Catenin signalling elicits such a diversity of biological outcomes are poorly understood. Here, we study alternatively spliced tcf7l2 in zebrafish and show that only splice variants that include exon 5 and an analogous human tcf7l2 variant can effectively provide compensatory repressor function to restore eye formation in embryos lacking tcf7l1a/tcf7l1b function. Knockdown of exon 5 specific tcf7l2 variants in tcf7l1a mutants also compromises eye formation and these variants can effectively repress Wnt pathway activity in reporter assays using Wnt target gene promoters. We show that the repressive activities of exon5-coded variants are likely explained by their interaction with Tle co-repressors. Furthermore, phosphorylated residues in Tcf7l2 coded exon5 facilitate repressor activity. Our studies suggest that developmentally regulated splicing of tcf7l2 can influence the transcriptional output of the Wnt pathway.

scholarly journals Myogenic differentiation potential of chicken mesenchymal stem cells from bone marrow

2021 ◽  
Author(s):  
Zhen Zhou ◽  
Changbin Zhao ◽  
Bolin Cai ◽  
Manting Ma ◽  
Shaofen Kong ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Horse Serum ◽  
Growth Characteristic ◽  
Normal Growth ◽  
Receptor Interaction ◽  
Differentiation Potential ◽  
Differential Adhesion

Abstract Background: Mesenchymal stem cells (MSCs) have the potential to multilineage differentiation, which can be used for a good model to provide critical insight of chicken muscle development. Differential adhesion method is one of the commonest methods to isolate MSCs based on the ability of plastic adhesion. 5-azacytidine (5-Aza), dexamethasone (DXMS), hydrocortisone (HC) and horse serum had been proved the potential to induce the myogenic differentiation of MSCs. However, the myogenic differentiation of MSCs is still poorly understood in chicken. In present study, we isolated chicken mesenchymal stem cells (cMSCs) from bone using 4-hour differential adhesion method and analyzed the myogenic effect of cMSCs treated with different method based on 5-Aza, DXMS, HC and horse serum.Results: cMSCs isolated by 4-hour differential adhesion method expressed MSCs special surface markers and presented normal growth characteristic. cMSCs showed great potential of myogenic differentiation by the treatment of 5-Aza and horse serum. RNA-sequence, GO and KGEE enrichment analysis revealed that this effect might be based on demethylation of 5-Aza and ECM-receptor interaction, focal adhesion, PI3K-Akt, p53, TGF-beta signaling pathways. Moreover, DXMS, HC and horse serum also presented potential of myogenic differentiation, but the effect was not as good as 5-Aza and horse serum method.Conclusions: cMSCs showed potential of myogenic differentiation by the treatment of 5-Aza and horse serum or DXMS, HC and horse serum.

scholarly journals Ketohexokinase: Expression and Localization of the Principal Fructose-metabolizing Enzyme

2009 ◽  
Vol 57 (8) ◽  
pp. 763-774 ◽  
Author(s):  
Christine P. Diggle ◽  
Michael Shires ◽  
Derek Leitch ◽  
David Brooke ◽  
Ian M. Carr ◽  
...  
Keyword(s):  
Western Blotting ◽  
Cellular Localization ◽  
Splice Variants ◽  
Immunohistochemical Localization ◽  
Nuclear Staining ◽  
Experimental Artifact ◽  
Alternatively Spliced ◽  
Metabolizing Enzyme ◽  
Knockout Animals

Ketohexokinase (KHK, also known as fructokinase) initiates the pathway through which most dietary fructose is metabolized. Very little is known about the cellular localization of this enzyme. Alternatively spliced KHK-C and KHK-A mRNAs are known, but the existence of the KHK-A protein isoform has not been demonstrated in vivo. Using antibodies to KHK for immunohistochemistry and Western blotting of rodent tissues, including those from mouse knockouts, coupled with RT-PCR assays, we determined the distribution of the splice variants. The highly expressed KHK-C isoform localized to hepatocytes in the liver and to the straight segment of the proximal renal tubule. In both tissues, cytoplasmic and nuclear staining was observed. The KHK-A mRNA isoform was observed exclusively in a range of other tissues, and by Western blotting, the presence of endogenous immunoreactive KHK-A protein was shown for the first time, proving that the KHK-A mRNA is translated into KHK-A protein in vivo, and supporting the suggestion that this evolutionarily conserved isoform is physiologically functional. However, the low levels of KHK-A expression prevented its immunohistochemical localization within these tissues. Our results highlight that the use of in vivo biological controls (tissues from knockout animals) is required to distinguish genuine KHK immunoreactivity from experimental artifact.

Shift from slow- to fast-twitch muscle fibres in skeletal muscle of newborn heterozygous and homozygous myostatin-knockout piglets

2019 ◽  
Vol 31 (10) ◽  
pp. 1628 ◽  
Author(s):  
Mei-Fu Xuan ◽  
Zhao-Bo Luo ◽  
Jun-Xia Wang ◽  
Qing Guo ◽  
Sheng-Zhong Han ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
Muscle Development ◽  
Transforming Growth Factor ◽  
Myogenic Differentiation ◽  
Muscle Fibres ◽  
Skeletal Muscle Development ◽  
Cross Sectional ◽  
Gene And Protein Expression ◽  
Fast Twitch

Myostatin (MSTN) is a member of the transforming growth factor-β superfamily that negatively regulates skeletal muscle development. A lack of MSTN induces muscle hypertrophy and increases formation of fast-twitch (Type II) muscle fibres. This study investigated muscle development in newborn heterozygous (MSTN+/−) and homozygous (MSTN−/−) MSTN-knockout piglets. Detailed morphological and gene and protein expression analyses were performed of the biceps femoris, semitendinosus and diaphragm of MSTN+/−, MSTN−/− and wild-type (WT) piglets. Haematoxylin–eosin staining revealed that the cross-sectional area of muscle fibres was significantly larger in MSTN-knockout than WT piglets. ATPase staining demonstrated that the percentage of Type IIb and IIa muscle fibres was significantly higher in MSTN−/− and MSTN+/− piglets respectively than in WT piglets. Western blotting showed that protein expression of myosin heavy chain-I was reduced in muscles of MSTN-knockout piglets. Quantitative reverse transcription–polymerase chain reaction revealed that, compared with WT piglets, myogenic differentiation factor (MyoD) mRNA expression in muscles was 1.3- to 2-fold higher in MSTN+/− piglets and 1.8- to 3.5-fold higher MSTN−/− piglets (P<0.05 and P<0.01 respectively). However, expression of myocyte enhancer factor 2C (MEF2C) mRNA in muscles was significantly lower in MSTN+/− than WT piglets (P<0.05). MSTN plays an important role in skeletal muscle development and regulates muscle fibre type by modulating the gene expression of MyoD and MEF2C in newborn piglets.

scholarly journals The transformer-2 and fruitless characterisation with developmental expression profiles of sex-determining genes in Bactrocera dorsalis and B. correcta

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kamoltip Laohakieat ◽  
Siriwan Isasawin ◽  
Sujinda Thanaphum
Keyword(s):  
Splice Variants ◽  
Expression Profiles ◽  
Bactrocera Dorsalis ◽  
Developmental Expression ◽  
Alternative Promoters ◽  
Downstream Effector ◽  
Effector Genes ◽  
Early Embryos ◽  
Alternatively Spliced ◽  
Tephritid Fruit Flies

Abstract Sex determination in tephritid fruit flies involves a signaling cascade of alternatively spliced genes. The Transformer (TRA) and Transformer-2 (TRA-2) complex establishes an autoregulatory loop switching sex-specific splicing of tra pre-mRNA in females. The TRA/TRA-2 complex also regulates the sex-specific splicing of downstream effector genes, doublesex (dsx) and fruitless (fru). In Ceratitis capitata, a Maleness-on the-Y (MoY) gene modulates sex-specifically spliced Cctra pre-mRNA and results in the breakdown of the Cctra autoregulatory loop in males. In this study, the tra-2 and fru genes were characterised in two key pests, Bactrocera dorsalis and B. correcta. The tra-2 genes showed high degrees of conservation among tephritids. The complex gene organisation for each of Bdfru and Bcfru were identified. There are sex-specific and non sex-specific transcripts generated by alternative promoters as found in Drosophila melanogaster and other insects. RNAi knockdown of Bdtra transcripts showed that BdTRA controls the sex-specific splicing of Bddsx and Bdfru pre-mRNAs. Developmental expression analysis shows that multiple splice variants of Bdtra and Bctra RNAs are present before and during cellular blastoderm formation and that the mature sex-specific variants become fixed later in embryogenesis. Furthermore, the BddsxM splice variants are found in early embryos at the beginning of gastulation, but BdfruM does not appear until the larval stage. We proposed that the zygotic tra loop is initiated in both female and male embryos before becoming automatised or abolished by MoY, respectively.

scholarly journals Bta-miR-24-3p Controls the Myogenic Differentiation and Proliferation of Fetal, Bovine, Skeletal Muscle-Derived Progenitor Cells by Targeting ACVR1B

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 859 ◽  
Author(s):  
Xin Hu ◽  
Yishen Xing ◽  
Ling Ren ◽  
Yahui Wang ◽  
Qian Li ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Progenitor Cells ◽  
Muscle Development ◽  
Myogenic Differentiation ◽  
Luciferase Assay ◽  
Skeletal Muscle Development ◽  
Cellular Events ◽  
Fetal Bovine ◽  
Bovine Skeletal Muscle ◽  
Differentiation And Proliferation

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this study, we report that bta-miR-24-3p promotes the myogenic differentiation of fetal bovine PDGFRα- progenitor cells. The expression of bta-miR-24-3p increased during myogenic differentiation. Overexpression of bta-miR-24-3p significantly promoted myogenic differentiation, but inhibited proliferation. A dual-luciferase assay identified ACVR1B as a direct target of bta-miR-24-3p. Similarly, knocking down ACVR1B by RNA interference also significantly inhibited proliferation and promoted the differentiation of bovine PDGFRα- progenitor cells. Thus, our study provides a mechanism in which bta-miR-24-3p regulates myogenesis by inhibiting ACVR1B expression.

scholarly journals Allosteric modulation of alternatively spliced Ca2+-activated Cl−channels TMEM16A by PI(4,5)P2and CaMKII

2020 ◽  
Vol 117 (48) ◽  
pp. 30787-30798
Author(s):  
Woori Ko ◽  
Seung-Ryoung Jung ◽  
Kwon-Woo Kim ◽  
Jun-Hee Yeon ◽  
Cheon-Gyu Park ◽  
...  
Keyword(s):  
Binding Site ◽  
In Silico ◽  
Single Channel ◽  
Splice Variants ◽  
Noise Analysis ◽  
Mechanistic Explanation ◽  
Intracellular Loop ◽  
Open Probability ◽  
In Silico Simulation ◽  
Alternatively Spliced

Transmembrane 16A (TMEM16A, anoctamin1), 1 of 10 TMEM16 family proteins, is a Cl−channel activated by intracellular Ca2+and membrane voltage. This channel is also regulated by the membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. We find that two splice variants of TMEM16A show different sensitivity to endogenous PI(4,5)P2degradation, where TMEM16A(ac) displays higher channel activity and more current inhibition by PI(4,5)P2depletion than TMEM16A(a). These two channel isoforms differ in the alternative splicing of the c-segment (exon 13). The current amplitude and PI(4,5)P2sensitivity of both TMEM16A(ac) and (a) are significantly strengthened by decreased free cytosolic ATP and by conditions that decrease phosphorylation by Ca2+/calmodulin-dependent protein kinase II (CaMKII). Noise analysis suggests that the augmentation of currents is due to a rise of single-channel current (i), but not of channel number (N) or open probability (PO). Mutagenesis points to arginine 486 in the first intracellular loop as a putative binding site for PI(4,5)P2, and to serine 673 in the third intracellular loop as a site for regulatory channel phosphorylation that modulates the action of PI(4,5)P2. In silico simulation suggests how phosphorylation of S673 allosterically and differently changes the structure of the distant PI(4,5)P2-binding site between channel splice variants with and without the c-segment exon. In sum, our study reveals the following: differential regulation of alternatively spliced TMEM16A(ac) and (a) by plasma membrane PI(4,5)P2, modification of these effects by channel phosphorylation, identification of the molecular sites, and mechanistic explanation by in silico simulation.

Functional Regulation of Alternatively Spliced Na+/Ca2+ Exchanger (NCX1) Isoforms

2006 ◽  
Vol 976 (1) ◽  
pp. 187-196 ◽  
Author(s):  
D. H. SCHULZE ◽  
S. K. POLUMURI ◽  
T. GILLE ◽  
A. RUKNUDIN
Keyword(s):  
Alternatively Spliced ◽  
Functional Regulation

scholarly journals The LIM-only protein FHL2 interacts with β-catenin and promotes differentiation of mouse myoblasts

2002 ◽  
Vol 159 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Bernd Martin ◽  
Richard Schneider ◽  
Stefanie Janetzky ◽  
Zoe Waibler ◽  
Petra Pandur ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Muscle Development ◽  
Target Genes ◽  
Myogenic Differentiation ◽  
Myoblast Differentiation ◽  
Lim Domains ◽  
Vitro Binding ◽  
Specific Proteins

FHL2 is a LIM-domain protein expressed in myoblasts but down-regulated in malignant rhabdomyosarcoma cells, suggesting an important role of FHL2 in muscle development. To investigate the importance of FHL2 during myoblast differentiation, we performed a yeast two-hybrid screen using a cDNA library derived from myoblasts induced for differentiation. We identified β-catenin as a novel interaction partner of FHL2 and confirmed the specificity of association by direct in vitro binding tests and coimmunoprecipitation assays from cell lysates. Deletion analysis of both proteins revealed that the NH2-terminal part of β-catenin is sufficient for binding in yeast, but addition of the first armadillo repeat is necessary for binding FHL2 in mammalian cells, whereas the presence of all four LIM domains of FHL2 is needed for the interaction. Expression of FHL2 counteracts β-catenin–mediated activation of a TCF/LEF-dependent reporter gene in a dose-dependent and muscle cell–specific manner. After injection into Xenopus embryos, FHL2 inhibited the β-catenin–induced axis duplication. C2C12 mouse myoblasts stably expressing FHL2 show increased myogenic differentiation reflected by accelerated myotube formation and expression of muscle-specific proteins. These data imply that FHL2 is a muscle-specific repressor of LEF/TCF target genes and promotes myogenic differentiation by interacting with β-catenin.

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