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The RNA-binding protein Staufen1 impairs myogenic differentiation via a c-myc-dependent mechanism.

Ravel-Chapuis A, Crawford TE, Blais-Crépeau ML, Bélanger G, Richer CT, Jasmin BJ - Mol. Biol. Cell (2014)

Bottom Line: Cells overexpressing Staufen1 differentiated poorly, as evidenced by reductions in the differentiation and fusion indices and decreases in MyoD, myogenin, MEF2A, and MEF2C, independently of Staufen-mediated mRNA decay.By contrast, the knockdown of Staufen1 decreased c-myc levels in myoblasts.Collectively our results show that Staufen1 is highly expressed during early stages of differentiation/development and that it can impair differentiation by regulating c-myc, thereby highlighting the multifunctional role of Staufen1 in skeletal muscle cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.

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Staufen1 decreases the expression of the myogenic markers myogenin and MyHC. (A) Representative Western blots showing myogenin and MyHC expression during differentiation of Staufen1-HA–stable C2C12 cells. β-Actin was used to show equal loading. (B, C) Relative quantification of myogenin and MyHC protein levels, respectively (n = 3). (D) Relative quantification of myogenin mRNA levels as determined by qRT-PCR (n = 4). Levels were normalized to cyclophylin-B. (E) C2C12 cells were transiently transfected with mouse Staufen1-HA or a control empty vector (pcDNA3). At 24 h after transfection, cells were switched to differentiation medium and differentiated for the indicated time. Western blots showing myogenin expression in transfected cells. β-Actin was used as a loading control. Asterisks indicate significance (*p ≤ 0.05, ***p ≤ 0.001).
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Figure 5: Staufen1 decreases the expression of the myogenic markers myogenin and MyHC. (A) Representative Western blots showing myogenin and MyHC expression during differentiation of Staufen1-HA–stable C2C12 cells. β-Actin was used to show equal loading. (B, C) Relative quantification of myogenin and MyHC protein levels, respectively (n = 3). (D) Relative quantification of myogenin mRNA levels as determined by qRT-PCR (n = 4). Levels were normalized to cyclophylin-B. (E) C2C12 cells were transiently transfected with mouse Staufen1-HA or a control empty vector (pcDNA3). At 24 h after transfection, cells were switched to differentiation medium and differentiated for the indicated time. Western blots showing myogenin expression in transfected cells. β-Actin was used as a loading control. Asterisks indicate significance (*p ≤ 0.05, ***p ≤ 0.001).

Mentions: To complement these morphological analyses and further characterize the differentiation defects, we analyzed expression of two key muscle genes expressed during the early and later stages of muscle differentiation. Protein and mRNA expression were determined via Western blot and real-time quantitative reverse transcription-PCR (qRT-PCR), respectively. Our results show that overexpression of Staufen1-HA induced a dramatic reduction (p < 0.001) in the expression of myogenin and MyHC in clones #15 and #25 as assessed by Western blotting (Figure 5, A–C). The decrease in myogenin expression was also confirmed (p < 0.05) at the transcript level by qRT-PCR (Figure 5D).


The RNA-binding protein Staufen1 impairs myogenic differentiation via a c-myc-dependent mechanism.

Ravel-Chapuis A, Crawford TE, Blais-Crépeau ML, Bélanger G, Richer CT, Jasmin BJ - Mol. Biol. Cell (2014)

Staufen1 decreases the expression of the myogenic markers myogenin and MyHC. (A) Representative Western blots showing myogenin and MyHC expression during differentiation of Staufen1-HA–stable C2C12 cells. β-Actin was used to show equal loading. (B, C) Relative quantification of myogenin and MyHC protein levels, respectively (n = 3). (D) Relative quantification of myogenin mRNA levels as determined by qRT-PCR (n = 4). Levels were normalized to cyclophylin-B. (E) C2C12 cells were transiently transfected with mouse Staufen1-HA or a control empty vector (pcDNA3). At 24 h after transfection, cells were switched to differentiation medium and differentiated for the indicated time. Western blots showing myogenin expression in transfected cells. β-Actin was used as a loading control. Asterisks indicate significance (*p ≤ 0.05, ***p ≤ 0.001).
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Related In: Results  -  Collection

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Figure 5: Staufen1 decreases the expression of the myogenic markers myogenin and MyHC. (A) Representative Western blots showing myogenin and MyHC expression during differentiation of Staufen1-HA–stable C2C12 cells. β-Actin was used to show equal loading. (B, C) Relative quantification of myogenin and MyHC protein levels, respectively (n = 3). (D) Relative quantification of myogenin mRNA levels as determined by qRT-PCR (n = 4). Levels were normalized to cyclophylin-B. (E) C2C12 cells were transiently transfected with mouse Staufen1-HA or a control empty vector (pcDNA3). At 24 h after transfection, cells were switched to differentiation medium and differentiated for the indicated time. Western blots showing myogenin expression in transfected cells. β-Actin was used as a loading control. Asterisks indicate significance (*p ≤ 0.05, ***p ≤ 0.001).
Mentions: To complement these morphological analyses and further characterize the differentiation defects, we analyzed expression of two key muscle genes expressed during the early and later stages of muscle differentiation. Protein and mRNA expression were determined via Western blot and real-time quantitative reverse transcription-PCR (qRT-PCR), respectively. Our results show that overexpression of Staufen1-HA induced a dramatic reduction (p < 0.001) in the expression of myogenin and MyHC in clones #15 and #25 as assessed by Western blotting (Figure 5, A–C). The decrease in myogenin expression was also confirmed (p < 0.05) at the transcript level by qRT-PCR (Figure 5D).

Bottom Line: Cells overexpressing Staufen1 differentiated poorly, as evidenced by reductions in the differentiation and fusion indices and decreases in MyoD, myogenin, MEF2A, and MEF2C, independently of Staufen-mediated mRNA decay.By contrast, the knockdown of Staufen1 decreased c-myc levels in myoblasts.Collectively our results show that Staufen1 is highly expressed during early stages of differentiation/development and that it can impair differentiation by regulating c-myc, thereby highlighting the multifunctional role of Staufen1 in skeletal muscle cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.

Show MeSH
Related in: MedlinePlus