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A new isoform of the histone demethylase JMJD2A/KDM4A is required for skeletal muscle differentiation.

ABSTRACT: In proliferating myoblasts, muscle specific genes are silenced by epigenetic modifications at their promoters, including histone H3K9 methylation. Derepression of the promoter of the gene encoding the myogenic factor myogenin (Myog) is key for initiation of muscle differentiation. The mechanism of H3K9 demethylation at the Myog promoter is unclear, however. Here, we identify an isoform of the histone demethylase JMJD2A/KDM4A that lacks the N-terminal demethylase domain (?N-JMJD2A). The amount of ?N-JMJD2A increases during differentiation of C2C12 myoblasts into myotubes. Genome-wide expression profiling and exon-specific siRNA knockdown indicate that, in contrast to the full-length protein, ?N-JMJD2A is necessary for myotube formation and muscle-specific gene expression. Moreover, ?N-JMJD2A promotes MyoD-induced conversion of NIH3T3 cells into muscle cells. ChIP-on-chip analysis indicates that ?N-JMJD2A binds to genes mainly involved in transcriptional control and that this binding is linked to gene activation. ?N-JMJD2A is recruited to the Myog promoter at the onset of differentiation. This binding is essential to promote the demethylation of H3K9me2 and H3K9me3. We conclude that induction of the ?N-JMJD2A isoform is crucial for muscle differentiation: by directing the removal of repressive chromatin marks at the Myog promoter, it promotes transcriptional activation of the Myog gene and thus contributes to initiation of muscle-specific gene expression.

SUBMITTER: Verrier L

PROVIDER: S-EPMC3107188 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

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A new isoform of the histone demethylase JMJD2A/KDM4A is required for skeletal muscle differentiation.

Verrier Laure L Escaffit Fabrice F Chailleux Catherine C Trouche Didier D Vandromme Marie M

PLoS genetics 20110602 6

In proliferating myoblasts, muscle specific genes are silenced by epigenetic modifications at their promoters, including histone H3K9 methylation. Derepression of the promoter of the gene encoding the myogenic factor myogenin (Myog) is key for initiation of muscle differentiation. The mechanism of H3K9 demethylation at the Myog promoter is unclear, however. Here, we identify an isoform of the histone demethylase JMJD2A/KDM4A that lacks the N-terminal demethylase domain (ΔN-JMJD2A). The amount of ...[more]

PMID: 21694756

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Project description:Background:A number of JmjC domain-containing histone demethylases have been identified and biochemically characterized in mammalian models and humans. JMJD2A is a transcriptional co-factor and enzyme that catalyzes the demethylation of histone H3 lysine 9 and 36 (H3K9 and H3K36). Here in this study, we reported the role of JMJD2A in human glioma. Methods:Quantitative real-time PCR and western blot were performed to analyzed JMJD2A expression in glioma. Log-rank was performed to plot the survival curve. JMJD2A was knocked or overexpressed with lentivirus. Cell proliferation and colony formation were performed to assess the effects of JMJD2A on glioma cell growth. Xenograft experiment was performed the evaluate the growth rate of glioma cells in vivo. The signaling pathway was analyzed with western blot and mTOR was inhibited with rapamycin. Results:Quantitative real-time PCR and western blot experiments revealed higher expression of JMJD2A and lower levels of H3K9me3/H3K36me3 in glioma tissues than that in normal brain tissues. We showed that knockdown of JMJD2A expression attenuated the growth and colony formation in three lines of glioma cells (U251, T98G, and U87MG), whereas JMJD2A overexpression resulted in opposing effects. Furthermore, we performed in vivo xenograft experiments and our data demonstrated that JMJD2A knockdown reduced the growth of glioma T98G cells in vivo. Further mechanism study implicated that JMJD2A activated the Akt-mTOR pathway and promoted protein synthesis in glioma cells via promoting phosphoinositide-dependent kinase-1 (PDK1) expression. The activation of the Akt-mTOR pathway was also validated in human glioma tissues. Finally, we showed that inhibition of mTOR with rapamycin blocked the effects of JMJD2A on protein synthesis, cell proliferation and colony formation of glioma cells. Conclusions:These findings demonstrated that JMJD2A regulated glioma growth and implicated that JMJD2A might be a promising target for intervention.

Dataset Information

A new isoform of the histone demethylase JMJD2A/KDM4A is required for skeletal muscle differentiation.

Publications

A new isoform of the histone demethylase JMJD2A/KDM4A is required for skeletal muscle differentiation.

Similar Datasets

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