Project description:Histone deacetylase 3 (HDAC3) is an epigenome-modifying enzyme that is required for normal mouse development and tissue-specific functions. In vitro, HDAC3 protein itself has minimal enzyme activity, but gains its histone deacetylation function from stable association with the conserved deacetylase activation domain (DAD) contained in nuclear receptor corepressors NCOR1 and SMRT. Here we show that HDAC3 enzyme activity is undetectable in mice bearing point mutations in the DAD of both NCOR1 and SMRT (NS-DADm), despite normal levels of HDAC3 protein. Local histone acetylation is increased, and genomic HDAC3 recruitment is reduced though not abrogated. Remarkably, the NS-DADm mice are born and live to adulthood, whereas genetic deletion of HDAC3 is embryonic lethal. These findings demonstrate that nuclear receptor corepressors are required for HDAC3 enzyme activity in vivo, and suggest that a deacetylase-independent function of HDAC3 may be required for life. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series.
Project description:Histone deacetylase 3 (HDAC3) is an epigenome-modifying enzyme that is required for normal mouse development and tissue-specific functions. In vitro, HDAC3 protein itself has minimal enzyme activity, but gains its histone deacetylation function from stable association with the conserved deacetylase activation domain (DAD) contained in nuclear receptor corepressors NCOR1 and SMRT. Here we show that HDAC3 enzyme activity is undetectable in mice bearing point mutations in the DAD of both NCOR1 and SMRT (NS-DADm), despite normal levels of HDAC3 protein. Local histone acetylation is increased, and genomic HDAC3 recruitment is reduced though not abrogated. Remarkably, the NS-DADm mice are born and live to adulthood, whereas genetic deletion of HDAC3 is embryonic lethal. These findings demonstrate that nuclear receptor corepressors are required for HDAC3 enzyme activity in vivo, and suggest that a deacetylase-independent function of HDAC3 may be required for life. This SuperSeries is composed of the SubSeries listed below.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Nuclear receptor corepressors (NCORs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3). In the liver, loss of HDAC3 causes a marked hepatosteatosis largely due to derepression of genes involved in lipid metabolism. Here we show that adult loss of both NCOR1 and 2 (dKO) in hepatocytes phenocopies the hepatomegalic fatty liver phenotype. In addition, dKO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCORs nor HDAC3, resulting in profound fasting hypoglycemia. This surprising HDAC3-independent activation function of NCOR1/2 was due to an unexpected loss of chromatin accessibility upon deletion of NCORs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCORs that is required for metabolic health.
Project description:Nuclear receptor corepressors (NCORs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3). In the liver, loss of HDAC3 causes a marked hepatosteatosis largely due to derepression of genes involved in lipid metabolism. Here we show that adult loss of both NCOR1 and 2 (dKO) in hepatocytes phenocopies the hepatomegalic fatty liver phenotype. In addition, dKO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCORs nor HDAC3, resulting in profound fasting hypoglycemia. This surprising HDAC3-independent activation function of NCOR1/2 was due to an unexpected loss of chromatin accessibility upon deletion of NCORs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCORs that is required for metabolic health.
Project description:Nuclear receptor corepressors (NCORs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3). In the liver, loss of HDAC3 causes a marked hepatosteatosis largely due to derepression of genes involved in lipid metabolism. Here we show that adult loss of both NCOR1 and 2 (dKO) in hepatocytes phenocopies the hepatomegalic fatty liver phenotype. In addition, dKO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCORs nor HDAC3, resulting in profound fasting hypoglycemia. This surprising HDAC3-independent activation function of NCOR1/2 was due to an unexpected loss of chromatin accessibility upon deletion of NCORs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCORs that is required for metabolic health.