Project description:DUX4 activates the first wave of zygotic gene expression in the early embryo. Mis-expression of DUX4 in skeletal muscle causes facioscapulohumeral dystrophy (FSHD), whereas expression in cancers suppresses IFNg-induction of MHC Class I and contributes to immune evasion. We show that the DUX4 protein broadly suppresses immune signaling pathways—including IFNg, IFNb, DDX58, IFIH1 and cGAS mediated pathways. A conserved region containing (L)LxxL(L) motifs in the DUX4 carboxyterminal domain (CTD) was necessary to suppress interferon stimulated genes (ISGs). Co-immunoprecipitation identified DUX4-CTD interaction with multiple immune signaling factors, including STAT1. The DUX4-CTD (L)LxxL(L) region interacts with phosphorylated STAT1, sequesters it in the nucleus, modestly reduces its DNA binding, and prevents STAT1 from inducing ISG transcription. Mouse Dux similarly interacted with STAT1 and suppressed IFNg induction of ISGs. These findings identify an evolved role of the DUXC family in modulating immune signaling pathways with implications for development, cancers, and FSHD.
Project description:Facioscapulohumeral dystrophy (FSHD) is one of the most common inherited muscular dystrophies. The causative gene remains controversial and the mechanism of pathophysiology unknown. Here we identify genes associated with germline and early stem cell development as targets of the DUX4 transcription factor, a leading candidate gene for FSHD. The genes regulated by DUX4 are reliably detected in FSHD muscle but not in controls, providing direct support for the model that misexpression of DUX4 is a causal factor for FSHD. Additionally, we show that DUX4 binds and activates LTR elements from a class of MaLR endogenous primate retrotransposons and suppresses the innate immune response to viral infection, at least in part through the activation of DEFB103, a human defensin that can inhibit muscle differentiation. These findings suggest specific mechanisms of FSHD pathology and identify candidate biomarkers for disease diagnosis and progression. Examine Dux4 full isoform binding sites in human fibroblast.
Project description:DUX4 is a germline transcription factor and a master regulator of zygotic genome activation. During early embryogenesis, DUX4 is crucial for maternal to zygotic transition at the 8-cell stage in order to overcome silencing of genes and enable transcription from the zygotic genome. In adult somatic cells, DUX4 expression is silenced and its activation in adult muscle cells causes the genetic disorder Facioscapulohumeral Muscular Dystrophy (FSHD). Here we show that herpesviruses actively induce DUX4 expression to promote viral transcription and replication. We demonstrate that HSV-1 immediate early proteins directly induce expression of DUX4 and its target genes including endogenous retroelements, which mimics zygotic genome activation. DUX4 directly binds to the viral genome, promotes viral transcription and genetic depletion of DUX4 by CRISPR/Cas9 abrogates viral replication. Our results show that viruses from alpha-, beta- and gamma-herpesvirus subfamilies induce DUX4 expression and downstream germline-specific genes and retroelements. Herpesviruses activate DUX4 expression in order to induce an early embryonic-like transcriptional program that prevents epigenetic silencing of the viral genome and facilitates herpesviral gene expression.
Project description:DUX4 is a germline transcription factor and a master regulator of zygotic genome activation. During early embryogenesis, DUX4 is crucial for maternal to zygotic transition at the 8-cell stage in order to overcome silencing of genes and enable transcription from the zygotic genome. In adult somatic cells, DUX4 expression is silenced and its activation in adult muscle cells causes the genetic disorder Facioscapulohumeral Muscular Dystrophy (FSHD). Here we show that herpesviruses actively induce DUX4 expression to promote viral transcription and replication. We demonstrate that HSV-1 immediate early proteins directly induce expression of DUX4 and its target genes including endogenous retroelements, which mimics zygotic genome activation. DUX4 directly binds to the viral genome, promotes viral transcription and genetic depletion of DUX4 by CRISPR/Cas9 abrogates viral replication. Our results show that viruses from alpha-, beta- and gamma-herpesvirus subfamilies induce DUX4 expression and downstream germline-specific genes and retroelements. Herpesviruses activate DUX4 expression in order to induce an early embryonic-like transcriptional program that prevents epigenetic silencing of the viral genome and facilitates herpesviral gene expression.
Project description:Facioscapulohumeral dystrophy (FSHD) is one of the most common inherited muscular dystrophies. The causative gene remains controversial and the mechanism of pathophysiology unknown. Here we identify genes associated with germline and early stem cell development as targets of the DUX4 transcription factor, a leading candidate gene for FSHD. The genes regulated by DUX4 are reliably detected in FSHD muscle but not in controls, providing direct support for the model that misexpression of DUX4 is a causal factor for FSHD. Additionally, we show that DUX4 binds and activates LTR elements from a class of MaLR endogenous primate retrotransposons and suppresses the innate immune response to viral infection, at least in part through the activation of DEFB103, a human defensin that can inhibit muscle differentiation. These findings suggest specific mechanisms of FSHD pathology and identify candidate biomarkers for disease diagnosis and progression. [Overexpression experiment] Quadruplicate total RNA samples were collected from control human primary myoblasts transduced with lentivirus carrying DUX4-fl, DUX4-s or GFP (MOI = 15) for 24 h and from untransduced myoblasts. [Defensin experiment] Quadruplicate samples were also collected from myoblasts and myotubes grown in media containing human beta-defensin 3 peptide or in control media.
Project description:DUX4 activates the first wave of zygotic gene expression in the early embryo. Mis-expression of DUX4 in skeletal muscle causes facioscapulohumeral dystrophy (FSHD), whereas expression in cancers suppresses IFNg-induction of MHC Class I and contributes to immune evasion. We show that the DUX4 protein broadly suppresses immune signaling pathways—including IFNg, IFNb, DDX58, IFIH1 and cGAS mediated pathways. A conserved region containing (L)LxxL(L) motifs in the DUX4 carboxyterminal domain (CTD) was necessary to suppress interferon stimulated genes (ISGs). Co-immunoprecipitation identified DUX4-CTD interaction with multiple immune signaling factors, including STAT1. The DUX4-CTD (L)LxxL(L) region interacts with phosphorylated STAT1, sequesters it in the nucleus, modestly reduces its DNA binding, and prevents STAT1 from inducing ISG transcription. Mouse Dux similarly interacted with STAT1 and suppressed IFNg induction of ISGs. These findings identify an evolved role of the DUXC family in modulating immune signaling pathways with implications for development, cancers, and FSHD.
Project description:DUX4 activates the first wave of zygotic gene expression in the early embryo. Mis-expression of DUX4 in skeletal muscle causes facioscapulohumeral dystrophy (FSHD), whereas expression in cancers suppresses IFNg-induction of MHC Class I and contributes to immune evasion. We show that the DUX4 protein broadly suppresses immune signaling pathways—including IFNg, IFNb, DDX58, IFIH1 and cGAS mediated pathways. A conserved region containing (L)LxxL(L) motifs in the DUX4 carboxyterminal domain (CTD) was necessary to suppress interferon stimulated genes (ISGs). Co-immunoprecipitation identified DUX4-CTD interaction with multiple immune signaling factors, including STAT1. The DUX4-CTD (L)LxxL(L) region interacts with phosphorylated STAT1, sequesters it in the nucleus, modestly reduces its DNA binding, and prevents STAT1 from inducing ISG transcription. Mouse Dux similarly interacted with STAT1 and suppressed IFNg induction of ISGs. These findings identify an evolved role of the DUXC family in modulating immune signaling pathways with implications for development, cancers, and FSHD.
Project description:Facioscapulohumeral dystrophy (FSHD) is one of the most common inherited muscular dystrophies. The causative gene remains controversial and the mechanism of pathophysiology unknown. Here we identify genes associated with germline and early stem cell development as targets of the DUX4 transcription factor, a leading candidate gene for FSHD. The genes regulated by DUX4 are reliably detected in FSHD muscle but not in controls, providing direct support for the model that misexpression of DUX4 is a causal factor for FSHD. Additionally, we show that DUX4 binds and activates LTR elements from a class of MaLR endogenous primate retrotransposons and suppresses the innate immune response to viral infection, at least in part through the activation of DEFB103, a human defensin that can inhibit muscle differentiation. These findings suggest specific mechanisms of FSHD pathology and identify candidate biomarkers for disease diagnosis and progression.
Project description:Facioscapulohumeral dystrophy (FSHD) is one of the most common inherited muscular dystrophies. The causative gene remains controversial and the mechanism of pathophysiology unknown. Here we identify genes associated with germline and early stem cell development as targets of the DUX4 transcription factor, a leading candidate gene for FSHD. The genes regulated by DUX4 are reliably detected in FSHD muscle but not in controls, providing direct support for the model that misexpression of DUX4 is a causal factor for FSHD. Additionally, we show that DUX4 binds and activates LTR elements from a class of MaLR endogenous primate retrotransposons and suppresses the innate immune response to viral infection, at least in part through the activation of DEFB103, a human defensin that can inhibit muscle differentiation. These findings suggest specific mechanisms of FSHD pathology and identify candidate biomarkers for disease diagnosis and progression.