STAC3 is required for myotube formation and myogenic differentiation in vertebrate skeletal muscle
- Authors
- Bower, N.I., Castillo, D.G., Cole, N.J., Hollway, G.E., Lee, H.T., Assinder, S., and Johnston, I.A.
- ID
- ZDB-PUB-121030-13
- Date
- 2012
- Source
- The Journal of biological chemistry 287(52): 43936-43949 (Journal)
- Registered Authors
- Cole, Nicholas, Johnston, Ian A.
- Keywords
- akt, insulin-like growth factor (IGF), mouse, mTOR, myogenesis, zebrafish
- MeSH Terms
-
- Animals
- Cell Differentiation/physiology*
- Cell Line
- Fish Proteins/biosynthesis*
- Fish Proteins/genetics
- G1 Phase Cell Cycle Checkpoints/physiology
- Gene Expression Profiling
- Gene Expression Regulation/physiology*
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/metabolism*
- Muscle Proteins/biosynthesis*
- Muscle Proteins/genetics
- Salmo salar/genetics
- Salmo salar/metabolism*
- Signal Transduction/physiology
- Zebrafish
- PubMed
- 23076145 Full text @ J. Biol. Chem.
STAC3 was identified as a nutritionally regulated gene from an Atlantic salmon subtractive hybridisation library with highest expression in skeletal muscle. Salmon STAC3 mRNA was highly correlated with myogenin and myoD1a expression during differentiation of a salmon primary myogenic culture and was regulated by amino acid availability. In zebrafish embryos, STAC3 was initially expressed in myotomal adaxial cells and in fast muscle fibres post-segmentation. Morpholino knockdown resulted in defects in myofibrillar protein assembly, particularly in slow muscle fibres, and decreased levels of the hedgehog receptor patched. The function of STAC3 was further characterised in vitro using the mammalian C2C12 myogenic cell line. STAC3 mRNA expression increased during the differentiation of the C2C12 myogenic cell line. Knockdown of STAC3 by RNAi inhibited myotube formation, and microarray analysis revealed that transcripts involved in cell cycle, focal adhesion, cytoskeleton and the pro-myogenic factors IGFBP-5 and IGF2 were down regulated. RNAi treated cells had suppressed AKT signalling and exogenous IGF2 was unable to rescue the phenotype, however, IGF/AKT signalling was not blocked. Overexpression of STAC3, which results in increased levels of IGFBP-5 mRNA, did not lead to increased differentiation. In synchronised cells, STAC3 mRNA was most abundant during the G1 phase of the cell cycle. RNAi treated cells were smaller, had higher proliferation rates and decreased proportion of cells in G1 phase when compared to controls, suggesting a role in the G1 phase checkpoint. These results identify STAC3 as a new gene required for myogenic differentiation and myofibrillar protein assembly in vertebrates.