Physiologically regulated alternative splicing patterns of fast troponin T RNA are conserved in mammals

1996 ◽  
Vol 270 (1) ◽  
pp. C298-C305 ◽  
Author(s):  
M. M. Briggs ◽  
F. Schachat
Keyword(s):  
Skeletal Muscle ◽  
Alternative Splicing ◽  
Nucleic Acid ◽  
Skeletal Muscles ◽  
Troponin T ◽  
Adult Rabbit ◽  
Rna Transcripts ◽  
Chemical Studies ◽  
Fast Twitch ◽  
Splicing Patterns

NH2-terminal isoforms of fast troponin T (TnT) are generated by alternative splicing of fast TnT RNA transcripts. Significantly different estimates for the number of isoforms have been obtained by nucleic acid and protein chemical studies. To resolve this controversy and to determine whether specific 5'-splicing patterns correlate with fiber phenotype, we generated representative populations of 5'-TnT cDNAs from the TnT mRNAs expressed in a set of physiologically and anatomically diverse skeletal muscles. Sequencing and restriction enzyme analyses revealed a total of nine cDNAs that encode the six adult and three perinatal NH2-terminal TnT variants previously identified. Three major 5'-splicing pathways (the TnT1f, TnT2f, and TnT3f patterns) account for more than 90% of the TnT mRNAs and proteins in adult rabbit skeletal muscle. Comparative studies in rats, mice, and humans show that these splicing patterns are conserved and that fast-twitch fibers that are primarily glycolytic utilize the TnT1f and TnT2f patterns preferentially, whereas fast-twitch fibers that are primarily oxidative use the TnT1f and TnT3f patterns preferentially.

Expression of avian Ca2+-ATPase in cultured mouse myogenic cells

1989 ◽  
Vol 9 (5) ◽  
pp. 1978-1986
Author(s):  
N J Karin ◽  
Z Kaprielian ◽  
D M Fambrough
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
C2c12 Cells ◽  
Cyanine Dye ◽  
Adult Rabbit ◽  
Base Pairs ◽  
Reading Frame ◽  
Cytoplasmic Vesicles ◽  
Fast Twitch ◽  
Chicken Skeletal Muscle

cDNA encoding Ca2+-ATPase was cloned from a chicken skeletal muscle library. The cDNA (termed FCa) comprised 3,239 base pairs, including an open reading frame encoding 994 amino acids which showed the highest degree of homology with the adult rabbit fast-twitch Ca2+-ATPase isoform (C. J. Brandl, S. de Leon, D. R. Martin, and D. H. MacLennan, J. Biol. Chem. 262:3768-3774, 1987). Radiolabeled FCa hybridized to a 3.2-kilobase transcript in chicken skeletal muscle RNA but not to cardiac muscle RNA, which confirmed its identity as encoding the fast Ca2+-ATPase isoenzyme. FCa was transfected into the mouse myogenic line C2C12, from which a protein of 100 kilodaltons was immunopurified by using a monoclonal antibody specific for the avian fast Ca2+-ATPase. Immunofluorescence microscopy of a line (designated C2FCa2) stably expressing the avian Ca2+-ATPase localized the protein to the nuclear envelope and a population of cytoplasmic vesicles. A similar pattern was observed when C2FCa2 cells were stained with DiOC6(3), a cyanine dye that labels endoplasmic reticulum and mitochondria (M. Terasaki, J. Song, J. R. Wong, M. J. Weiss, and L. B. Chen, Cell 38:101-108, 1984). We conclude that the avian Ca2+-ATPase fast isoform is expressed and correctly targeted to the endoplasmic reticulum in mouse C2C12 cells.

Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats

1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Skeletal Muscles ◽  
Female Rats ◽  
Mrna Levels ◽  
Aged Rats ◽  
Adult Rats ◽  
Adult Age ◽  
Slow Twitch ◽  
Fast Twitch

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.

scholarly journals Expression of avian Ca2+-ATPase in cultured mouse myogenic cells.

1989 ◽  
Vol 9 (5) ◽  
pp. 1978-1986 ◽  
Author(s):  
N J Karin ◽  
Z Kaprielian ◽  
D M Fambrough
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
C2c12 Cells ◽  
Cyanine Dye ◽  
Adult Rabbit ◽  
Base Pairs ◽  
Reading Frame ◽  
Cytoplasmic Vesicles ◽  
Fast Twitch ◽  
Chicken Skeletal Muscle

cDNA encoding Ca2+-ATPase was cloned from a chicken skeletal muscle library. The cDNA (termed FCa) comprised 3,239 base pairs, including an open reading frame encoding 994 amino acids which showed the highest degree of homology with the adult rabbit fast-twitch Ca2+-ATPase isoform (C. J. Brandl, S. de Leon, D. R. Martin, and D. H. MacLennan, J. Biol. Chem. 262:3768-3774, 1987). Radiolabeled FCa hybridized to a 3.2-kilobase transcript in chicken skeletal muscle RNA but not to cardiac muscle RNA, which confirmed its identity as encoding the fast Ca2+-ATPase isoenzyme. FCa was transfected into the mouse myogenic line C2C12, from which a protein of 100 kilodaltons was immunopurified by using a monoclonal antibody specific for the avian fast Ca2+-ATPase. Immunofluorescence microscopy of a line (designated C2FCa2) stably expressing the avian Ca2+-ATPase localized the protein to the nuclear envelope and a population of cytoplasmic vesicles. A similar pattern was observed when C2FCa2 cells were stained with DiOC6(3), a cyanine dye that labels endoplasmic reticulum and mitochondria (M. Terasaki, J. Song, J. R. Wong, M. J. Weiss, and L. B. Chen, Cell 38:101-108, 1984). We conclude that the avian Ca2+-ATPase fast isoform is expressed and correctly targeted to the endoplasmic reticulum in mouse C2C12 cells.

Expression and functional properties of four slow skeletal troponin T isoforms in rat muscles

2005 ◽  
Vol 289 (2) ◽  
pp. C437-C443 ◽  
Author(s):  
P. Kischel ◽  
B. Bastide ◽  
M. Muller ◽  
F. Dubail ◽  
F. Offredi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Molecular Weight ◽  
Expression Pattern ◽  
Functional Properties ◽  
Soleus Muscle ◽  
Skeletal Muscles ◽  
Troponin T ◽  
Relative Proportion ◽  
Muscle Fibers ◽  
Low Molecular Weight

We investigated the expression and functional properties of slow skeletal troponin T (sTnT) isoforms in rat skeletal muscles. Four sTnT cDNAs were cloned from the slow soleus muscle. Three isoforms were found to be similar to sTnT1, sTnT2, and sTnT3 isoforms described in mouse muscles. A new rat isoform, with a molecular weight slightly higher than that of sTnT3, was discovered. This fourth isoform had never been detected previously in any skeletal muscle and was therefore called sTnTx. From both expression pattern and functional measurements, it appears that sTnT isoforms can be separated into two classes, high-molecular-weight (sTnT1, sTnT2) and low-molecular-weight (sTnTx, sTnT3) isoforms. By comparison to the apparent migration pattern of the four recombinant sTnT isoforms, the newly described low-molecular-weight sTnTx isoform appeared predominantly and typically expressed in fast skeletal muscles, whereas the higher-molecular-weight isoforms were more abundant in slow soleus muscle. The relative proportion of the sTnT isoforms in the soleus was not modified after exposure to hindlimb unloading (HU), known to induce a functional atrophy and a slow-to-fast isoform transition of several myofibrillar proteins. Functional data gathered from replacement of endogenous troponin complexes in skinned muscle fibers showed that the sTnT isoforms modified the Ca2+ activation characteristics of single skeletal muscle fibers, with sTnT2 and sTnT1 conferring a similar increase in Ca2+ affinity higher than that caused by low-molecular-weight isoforms sTnTx and sTnT3. Thus we show for the first time the presence of sTnT in fast muscle fibers, and our data show that the changes in neuromuscular activity on HU are insufficient to alter the sTnT expression pattern.

scholarly journals A high‐fat diet impairs alternative splicing of the troponin T pre‐mRNA in skeletal muscle

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Scot R Kimball ◽  
Rudolf J Schilder ◽  
Elisabeth A Charleston ◽  
Leonard S Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Alternative Splicing ◽  
High Fat Diet ◽  
Troponin T ◽  
High Fat

scholarly journals Tissue-specific and developmentally regulated alternative splicing in mouse skeletal muscle ryanodine receptor mRNA

1995 ◽  
Vol 305 (2) ◽  
pp. 373-378 ◽  
Author(s):  
A Futatsugi ◽  
G Kuwajima ◽  
K Mikoshiba
Keyword(s):  
Skeletal Muscle ◽  
Alternative Splicing ◽  
Ryanodine Receptor ◽  
Splice Variants ◽  
Amino Acid Sequences ◽  
Pcr Analysis ◽  
Developmentally Regulated ◽  
Tissue Specific ◽  
Mouse Skeletal Muscle ◽  
Splicing Patterns

The ryanodine receptor is a channel for Ca2+ release from intracellular stores. By PCR analysis, we identified two alternatively spliced regions in mRNA of the mouse skeletal muscle ryanodine receptor (sRyR). The splice variants were characterized by the presence or absence of 15 bp (ASI) and 18 bp (ASII) exons. The exclusion of these exons results in the absence of the regions corresponding to Ala3481-Gln3485 and Val3865-Asn3870, respectively, of rabbit sRyR; these amino acid sequences exist in the modulatory region, where sites for phosphorylation and binding of Ca2+, calmodulin and ATP are postulated to be. We also detected sRyR in brain and heart as well as in skeletal muscle, and the splicing patterns were found to be tissue-specific. Only the ASII-lacking isoform was detected in heart, whereas in other tissues the ASII-containing isoform was predominant. The splicing patterns were also found to change during development. In skeletal muscle, the ASI-containing isoform increased gradually from embryo to adult. The ASII-lacking isoform abruptly increased upon birth, but the ASII-containing isoform increased steadily afterwards. In cerebrum, the ratio of the ASII-containing isoform to the ASII-lacking one increased abruptly during embryonic days 14 and 18. These findings suggest that the alternative splicing of ASI and ASII, by affecting the modulatory region, generates functionally different sRyR isoforms in a tissue-specific and developmentally regulated manner.

Phorbol esters affect skeletal muscle glucose transport in a fiber type-specific manner

2004 ◽  
Vol 287 (2) ◽  
pp. E305-E309 ◽  
Author(s):  
David C. Wright ◽  
Paige C. Geiger ◽  
Mark J. Rheinheimer ◽  
Dong Ho Han ◽  
John O. Holloszy
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Insulin Signaling ◽  
Skeletal Muscles ◽  
Phorbol Esters ◽  
Serine Phosphorylation ◽  
Slow Twitch ◽  
Fast Twitch

Recent evidence has shown that activation of lipid-sensitive protein kinase C (PKC) isoforms leads to skeletal muscle insulin resistance. However, earlier studies demonstrated that phorbol esters increase glucose transport in skeletal muscle. The purpose of the present study was to try to resolve this discrepancy. Treatment with the phorbol ester 12-deoxyphorbol-13-phenylacetate 20-acetate (dPPA) led to an ∼3.5-fold increase in glucose transport in isolated fast-twitch epitrochlearis and flexor digitorum brevis muscles. Phorbol ester treatment was additive to a maximally effective concentration of insulin in fast-twitch skeletal muscles. Treatment with dPPA did not affect insulin signaling in the epitrochlearis. In contrast, phorbol esters had no effect on basal glucose transport and inhibited maximally insulin-stimulated glucose transport ∼50% in isolated slow-twitch soleus muscle. Furthermore, dPPA treatment inhibited the insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and the threonine and serine phosphorylation of PKB by ∼50% in the soleus. dPPA treatment also caused serine phosphorylation of IRS-1 in the slow-twitch soleus muscle. In conclusion, our results show that phorbol esters stimulate glucose transport in fast-twitch skeletal muscles and inhibit insulin signaling in slow-twitch soleus muscle of rats. These findings suggest that mechanisms other than PKC activation mediate lipotoxicity-induced whole body insulin resistance.

scholarly journals Effects of age and hindlimb immobilization and remobilization on fast troponin T precursor mRNA alternative splicing in rat gastrocnemius muscle

2016 ◽  
Vol 41 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Suhana Ravi ◽  
Rudolf J. Schilder ◽  
Arthur S. Berg ◽  
Scot R. Kimball
Keyword(s):  
Skeletal Muscle ◽  
Alternative Splicing ◽  
Muscle Mass ◽  
Relative Abundance ◽  
Muscle Function ◽  
Gastrocnemius Muscle ◽  
Troponin T ◽  
Splice Form ◽  
Cross Sectional ◽  
Precursor Mrna

Fast skeletal muscle troponin T (TNNT3) is an important component of the skeletal muscle contractile machinery. The precursor mRNA (pre-mRNA) encoding TNNT3 is alternatively spliced, and changes in the pattern of TNNT3 splice form expression are associated with alterations in thin-filament calcium sensitivity and force production during muscle contraction and thereby regulate muscle function. Interestingly, during aging, the muscle force/cross-sectional area is reduced, suggesting that loss of mass does not completely account for the impaired muscle function that develops during the aging process. Therefore, in this study, we tested the hypothesis that age and changes in muscle loading are associated with alterations in Tnnt3 alternative splicing in the rat gastrocnemius muscle. We found that the relative abundance of several Tnnt3 splice forms varied significantly with age among 2-, 9-, and 18-month-old rats and that the pattern correlated with changes in body mass rather than muscle mass. Hindlimb immobilization for 7 days resulted in dramatic alterations in splice form relative abundance such that the pattern was similar to that observed in lighter animals. Remobilization for 7 days restored the splicing pattern toward that observed in the nonimmobilized limb, even though muscle mass had not yet begun to recover. In conclusion, the results suggest that Tnnt3 pre-mRNA alternative splicing is modulated rapidly (i.e., within days) in response to changes in the load placed on the muscle. Moreover, the results show that restoration of Tnnt3 alternative splicing to control patterns is initiated prior to an increase in muscle mass.

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