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Mammalian Mss51 is a Skeletal Muscle-Specific Gene Modulating Cellular Metabolism

View Article: PubMed Central - PubMed

ABSTRACT

Background:: The transforming growth factor β (TGF-β) signaling pathways modulate skeletal muscle growth, regeneration, and cellular metabolism. Several recent gene expression studies have shown that inhibition of myostatin and TGF-β1 signaling consistently leads to a significant reduction in expression of Mss51, also named Zmynd17. The function of mammalian Mss51 is unknown although a putative homolog in yeast is a mitochondrial translational activator.

Objective:: The objective of this work was to characterize mammalian MSS51.

Methods:: Quantitative RT-PCR and immunoblot of subcellular fractionation were used to determine expression patterns and localization of Mss51. The CRISPR/Cas9 system was used to reduce expression of Mss51 in C2C12 myoblasts and the function of Mss51 was evaluated in assays of proliferation, differentiation and cellular metabolism.

Results:: Mss51 was predominantly expressed in skeletal muscle and in those muscles dominated by fast-twitch fibers. In vitro, its expression was upregulated upon differentiation of C2C12 myoblasts into myotubes. Expression of Mss51 was modulated in response to altered TGF-β family signaling. In human muscle, MSS51 localized to the mitochondria. Its genetic disruption resulted in increased levels of cellular ATP, β-oxidation, glycolysis, and oxidative phosphorylation.

Conclusions:: Mss51 is a novel, skeletal muscle-specific gene and a key target of myostatin and TGF-β1 signaling. Unlike myostatin, TGF-β1 and IGF-1, Mss51 does not regulate myoblast proliferation or differentiation. Rather, Mss51 appears to be one of the effectors of these growth factors on metabolic processes including fatty acid oxidation, glycolysis and oxidative phosphorylation.

No MeSH data available.


Mss51 tissue expression. (A) Mss51 mRNA expression measured by qRT-PCR in brain, heart, kidney, liver, small intestine, diaphragm, and quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the quantity found in the brain using the reference gene Pgk1 (n = 3). (B) Mss51 mRNA expression in soleus, diaphragm, long head of triceps brachii, extensor digitorum longus, and white vastus lateralis of the quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the expression levels found in the soleus using reference genes Pgk1 and TBP (n = 3). (C) MSS51 expression across human tissue types determined by RNA-seq from the Genotype-Tissue Expression (GTEx) Portal showing MSS51 reads per kilobase per million reads mapped (RPKM). Data were downloaded from GTEx Portal on June 17, 2015. For qRT-PCR experiments, groups were significantly different from each other as determined by a one-way ANOVA (n = 3, p <  0.01) and Bonferroni post hoc comparisons. Different letters above each bar signify statistically significant differences between the means in each group at p <  0.05.
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jnd-2-4-jnd150119-g002: Mss51 tissue expression. (A) Mss51 mRNA expression measured by qRT-PCR in brain, heart, kidney, liver, small intestine, diaphragm, and quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the quantity found in the brain using the reference gene Pgk1 (n = 3). (B) Mss51 mRNA expression in soleus, diaphragm, long head of triceps brachii, extensor digitorum longus, and white vastus lateralis of the quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the expression levels found in the soleus using reference genes Pgk1 and TBP (n = 3). (C) MSS51 expression across human tissue types determined by RNA-seq from the Genotype-Tissue Expression (GTEx) Portal showing MSS51 reads per kilobase per million reads mapped (RPKM). Data were downloaded from GTEx Portal on June 17, 2015. For qRT-PCR experiments, groups were significantly different from each other as determined by a one-way ANOVA (n = 3, p <  0.01) and Bonferroni post hoc comparisons. Different letters above each bar signify statistically significant differences between the means in each group at p <  0.05.

Mentions: The data are presented as mean±standard error of the mean with the exception of Fig. 2 C, which presents data in box-and-whiskers format with the median, quartiles, and outliers depicted. For qRT-PCR analysis, statistical analysis was performed using qbase+. For all other experiments, statistical analysis was performed using SigmaPlot 11 (SyStat Software, Chicago, IL). When two groups were compared, differences were analyzed with a two-way Student’s t test. For more than two groups, differences were compared using one-way analysis of variance (ANOVA) with Bonferroni post hoc comparisons. Probability (p) values less than 0.05 were considered statistically significant.


Mammalian Mss51 is a Skeletal Muscle-Specific Gene Modulating Cellular Metabolism
Mss51 tissue expression. (A) Mss51 mRNA expression measured by qRT-PCR in brain, heart, kidney, liver, small intestine, diaphragm, and quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the quantity found in the brain using the reference gene Pgk1 (n = 3). (B) Mss51 mRNA expression in soleus, diaphragm, long head of triceps brachii, extensor digitorum longus, and white vastus lateralis of the quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the expression levels found in the soleus using reference genes Pgk1 and TBP (n = 3). (C) MSS51 expression across human tissue types determined by RNA-seq from the Genotype-Tissue Expression (GTEx) Portal showing MSS51 reads per kilobase per million reads mapped (RPKM). Data were downloaded from GTEx Portal on June 17, 2015. For qRT-PCR experiments, groups were significantly different from each other as determined by a one-way ANOVA (n = 3, p <  0.01) and Bonferroni post hoc comparisons. Different letters above each bar signify statistically significant differences between the means in each group at p <  0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4664537&req=5

jnd-2-4-jnd150119-g002: Mss51 tissue expression. (A) Mss51 mRNA expression measured by qRT-PCR in brain, heart, kidney, liver, small intestine, diaphragm, and quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the quantity found in the brain using the reference gene Pgk1 (n = 3). (B) Mss51 mRNA expression in soleus, diaphragm, long head of triceps brachii, extensor digitorum longus, and white vastus lateralis of the quadriceps of 10– 12 week-old female C57BL/6J mice, normalized to the expression levels found in the soleus using reference genes Pgk1 and TBP (n = 3). (C) MSS51 expression across human tissue types determined by RNA-seq from the Genotype-Tissue Expression (GTEx) Portal showing MSS51 reads per kilobase per million reads mapped (RPKM). Data were downloaded from GTEx Portal on June 17, 2015. For qRT-PCR experiments, groups were significantly different from each other as determined by a one-way ANOVA (n = 3, p <  0.01) and Bonferroni post hoc comparisons. Different letters above each bar signify statistically significant differences between the means in each group at p <  0.05.
Mentions: The data are presented as mean±standard error of the mean with the exception of Fig. 2 C, which presents data in box-and-whiskers format with the median, quartiles, and outliers depicted. For qRT-PCR analysis, statistical analysis was performed using qbase+. For all other experiments, statistical analysis was performed using SigmaPlot 11 (SyStat Software, Chicago, IL). When two groups were compared, differences were analyzed with a two-way Student’s t test. For more than two groups, differences were compared using one-way analysis of variance (ANOVA) with Bonferroni post hoc comparisons. Probability (p) values less than 0.05 were considered statistically significant.

View Article: PubMed Central - PubMed

ABSTRACT

Background:: The transforming growth factor &beta; (TGF-&beta;) signaling pathways modulate skeletal muscle growth, regeneration, and cellular metabolism. Several recent gene expression studies have shown that inhibition of myostatin and TGF-&beta;1 signaling consistently leads to a significant reduction in expression of Mss51, also named Zmynd17. The function of mammalian Mss51 is unknown although a putative homolog in yeast is a mitochondrial translational activator.

Objective:: The objective of this work was to characterize mammalian MSS51.

Methods:: Quantitative RT-PCR and immunoblot of subcellular fractionation were used to determine expression patterns and localization of Mss51. The CRISPR/Cas9 system was used to reduce expression of Mss51 in C2C12 myoblasts and the function of Mss51 was evaluated in assays of proliferation, differentiation and cellular metabolism.

Results:: Mss51 was predominantly expressed in skeletal muscle and in those muscles dominated by fast-twitch fibers. In vitro, its expression was upregulated upon differentiation of C2C12 myoblasts into myotubes. Expression of Mss51 was modulated in response to altered TGF-&beta; family signaling. In human muscle, MSS51 localized to the mitochondria. Its genetic disruption resulted in increased levels of cellular ATP, &beta;-oxidation, glycolysis, and oxidative phosphorylation.

Conclusions:: Mss51 is a novel, skeletal muscle-specific gene and a key target of myostatin and TGF-&beta;1 signaling. Unlike myostatin, TGF-&beta;1 and IGF-1, Mss51 does not regulate myoblast proliferation or differentiation. Rather, Mss51 appears to be one of the effectors of these growth factors on metabolic processes including fatty acid oxidation, glycolysis and oxidative phosphorylation.

No MeSH data available.