Abstract
Sox8 belongs to a family of transcription regulators characterized by a unique DNA-binding domain known as the high mobility group box. Many Sox proteins play fundamental roles in vertebrate development and differentiation processes. Expression of Sox8 is strong during embryonic muscle development and gradually declines postnatally. In this study, we report that in adult skeletal muscle Sox8 is confined to satellite cells. Down-regulation during myogenic differentiation was also detected in cell culture systems and occurred in parallel with down-regulation of the related Sox9. Overexpression of Sox8 or Sox9 on the other hand disrupted myoblasts in their ability to form myotubes. Concomitantly, expression of MyoD and myogenin decreased and basal as well as MyoD-induced activities of the myogenin promoter were strongly reduced in a Sox8-dependent manner. Our data suggest that Sox8 acts as a specific negative regulator of skeletal muscle differentiation, possibly by interfering with the function of myogenic basic helix-loop-helix proteins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD34 / biosynthesis
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Cell Culture Techniques
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Cell Differentiation
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Cell Line
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DNA-Binding Proteins / biosynthesis
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DNA-Binding Proteins / metabolism
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DNA-Binding Proteins / physiology*
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Down-Regulation
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Gene Expression Regulation
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Green Fluorescent Proteins
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High Mobility Group Proteins / biosynthesis
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Luciferases / metabolism
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Luminescent Proteins / metabolism
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Mice
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Mice, Inbred C3H
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Microscopy, Fluorescence
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Muscle, Skeletal / metabolism
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Muscles / embryology
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Muscles / metabolism*
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MyoD Protein / metabolism
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Plasmids / metabolism
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Promoter Regions, Genetic
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Protein Structure, Tertiary
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RNA / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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SOX9 Transcription Factor
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SOXC Transcription Factors
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SOXE Transcription Factors
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Time Factors
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Transcription Factors / biosynthesis
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Transcription Factors / metabolism
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Transcription Factors / physiology*
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Transfection
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beta-Galactosidase / metabolism
Substances
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Antigens, CD34
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DNA-Binding Proteins
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High Mobility Group Proteins
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Luminescent Proteins
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MyoD Protein
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SOX9 Transcription Factor
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SOXC Transcription Factors
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SOXE Transcription Factors
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Sox10 protein, mouse
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Sox11 protein, mouse
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Sox8 protein, mouse
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Sox9 protein, mouse
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Transcription Factors
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Green Fluorescent Proteins
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RNA
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Luciferases
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beta-Galactosidase