Project description:The bromodomain and extraterminal (BET) protein BRD4 is a therapeutic target in acute myeloid leukemia (AML). Here, we demonstrate that the AML maintenance function of BRD4 requires its interaction with NSD3, which belongs to a subfamily of H3K36 methyltransferases. Unexpectedly, AML cells were found to only require a short isoform of NSD3 that lacks the methyltransferase domain. We show that NSD3-short is an adaptor protein that sustains leukemia by linking BRD4 to the CHD8 chromatin remodeler, by using a PWWP chromatin reader module, and by employing an acidic transactivation domain. Genetic targeting of NSD3 or CHD8 mimics the phenotypic and transcriptional effects of BRD4 inhibition. Furthermore, BRD4, NSD3, and CHD8 colocalize across the AML genome, and each is released from super-enhancer regions upon chemical inhibition of BET bromodomains. These findings suggest that BET inhibitors exert therapeutic effects in leukemia by evicting BRD4-NSD3-CHD8 complexes from chromatin to suppress transcription. ChIP-Seq for regulatory factors of BRD4, NSD3, CHD8 and histone modification H3K36me2 in MLL-AF9 transformed acute myeloid leukemia cells (RN2)
Project description:The bromodomain and extraterminal (BET) protein BRD4 is a therapeutic target in acute myeloid leukemia (AML). Here, we demonstrate that the AML maintenance function of BRD4 requires its interaction with NSD3, which belongs to a subfamily of H3K36 methyltransferases. Unexpectedly, AML cells were found to only require a short isoform of NSD3 that lacks the methyltransferase domain. We show that NSD3-short is an adaptor protein that sustains leukemia by linking BRD4 to the CHD8 chromatin remodeler, by using a PWWP chromatin reader module, and by employing an acidic transactivation domain. Genetic targeting of NSD3 or CHD8 mimics the phenotypic and transcriptional effects of BRD4 inhibition. Furthermore, BRD4, NSD3, and CHD8 colocalize across the AML genome, and each is released from super-enhancer regions upon chemical inhibition of BET bromodomains. These findings suggest that BET inhibitors exert therapeutic effects in leukemia by evicting BRD4-NSD3-CHD8 complexes from chromatin to suppress transcription. PolyA+ (illumine TruSeq)/not-so-random (NSR) primers selected RNA-Seq for shRNA/sgRNA-expressing MLL-AF9 transformed acute myeloid leukemia cells (RN2).
Project description:The bromodomain and extraterminal (BET) protein BRD4 is a therapeutic target in acute myeloid leukemia (AML). Here, we demonstrate that the AML maintenance function of BRD4 requires its interaction with NSD3, which belongs to a subfamily of H3K36 methyltransferases. Unexpectedly, AML cells were found to only require a short isoform of NSD3 that lacks the methyltransferase domain. We show that NSD3-short is an adaptor protein that sustains leukemia by linking BRD4 to the CHD8 chromatin remodeler, by using a PWWP chromatin reader module, and by employing an acidic transactivation domain. Genetic targeting of NSD3 or CHD8 mimics the phenotypic and transcriptional effects of BRD4 inhibition. Furthermore, BRD4, NSD3, and CHD8 colocalize across the AML genome, and each is released from super-enhancer regions upon chemical inhibition of BET bromodomains. These findings suggest that BET inhibitors exert therapeutic effects in leukemia by evicting BRD4-NSD3-CHD8 complexes from chromatin to suppress transcription.
Project description:The bromodomain and extraterminal (BET) protein BRD4 is a therapeutic target in acute myeloid leukemia (AML). Here, we demonstrate that the AML maintenance function of BRD4 requires its interaction with NSD3, which belongs to a subfamily of H3K36 methyltransferases. Unexpectedly, AML cells were found to only require a short isoform of NSD3 that lacks the methyltransferase domain. We show that NSD3-short is an adaptor protein that sustains leukemia by linking BRD4 to the CHD8 chromatin remodeler, by using a PWWP chromatin reader module, and by employing an acidic transactivation domain. Genetic targeting of NSD3 or CHD8 mimics the phenotypic and transcriptional effects of BRD4 inhibition. Furthermore, BRD4, NSD3, and CHD8 colocalize across the AML genome, and each is released from super-enhancer regions upon chemical inhibition of BET bromodomains. These findings suggest that BET inhibitors exert therapeutic effects in leukemia by evicting BRD4-NSD3-CHD8 complexes from chromatin to suppress transcription.
Project description:Sequencing studies of autism spectrum disorder (ASD) cases have revealed a causal role for mutations to chromatin remodeling genes. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeler with one of the highest de novo mutation rates in sporadic ASD. However, the relationship between CHD8 genomic function and autism-relevant biology remains poorly elucidated. CHD8 binding studies have relied on Chromatin Immunoprecipitation followed by sequencing (ChIP-seq), but these datasets exhibit significant variation. ChIP-seq has technical limitations in the context of weak or indirect protein-DNA interactions or when high-performance antibodies are unavailable. Thus, complementary approaches are needed to establish CHD8 genomic targets. Here we used Targeted DamID in utero to characterize CHD8 binding activity in the developing embryonic mouse cortex. CHD8 Targeted DamID followed by sequencing (CHD8 TaDa-seq) revealed binding at previously identified genomic targets as well as at genes sensitive to Chd8 haploinsufficiency. CHD8 TaDa-seq showed greater sensitivity for CHD8 binding near a subset of genes specific to brain development and neuron function. These studies establish TaDa-seq as a useful alternative for mapping protein-DNA interactions in vivo and provide insights into the relationship between chromatin remodeling by CHD8 and autism-relevant pathophysiology associated with CHD8 mutations.
Project description:The loss-of-function mutations in the chromatin remodeler CHD8, a high-risk factor in autism spectrum disorder (ASD), lead to severe developmental delay, however, the underlying mechanisms remains elusive. Here, we use transcriptome and genomic occupancy reveal that CHD8 regulates chromatin accessibility and activates neurogenesis-related genes for cortical neurogenesis.
Project description:Autism spectrum disorders (ASD) are ~4-times more common in males than females, and CHD8 (a chromatin remodeler)-related ASD shows a strong male bias (~5:1), although the underlying mechanism remains unclear. Chd8-mutant mice with a C-terminal protein-truncating mutation (N2373X) display male-preponderant behavioral deficits as juveniles and adults, although whether this also applies to other Chd8 mutations remains unknown. Here we report that new Chd8-mutant mice with a stronger N-terminal protein-truncating mutation (S62X) display male-preponderant autistic-like behaviors at juvenile stages, but as adults, both males and females share behavioral deficits. Excitatory synaptic transmission is suppressed and enhanced in male and female juvenile Chd8+/S62X mice, respectively, but similarly enhanced in adults. ASD-like transcriptomic changes occur monophasically in newborn and juvenile (but not adult) males but biphasically in newborn and adult (not juvenile) females. Therefore, a strong CHD8 mutation induces early-onset ASD-like phenotypes in males but late-onset phenotypes in females after juvenile-stage female protection.
Project description:The chromatin remodeler CHD8 is among the most frequently mutated genes in autism spectrum disorder (ASD). CHD8 has a dosage-sensitive role in ASD but when and how it becomes critical to human social function is unclear. Here, we conducted genomic analyses of heterozygous and homozygous Chd8 mouse embryonic stem cells and differentiated neural progenitors. We identify dosage-sensitive CHD8 transcriptional targets, sites of regulated accessibility, and an unexpected cooperation with SOX transcription factors. Collectively, our findings reveal that CHD8 negatively regulates expression of neuronal genes to maintain pluripotency and also during differentiation. Thus, CHD8 is essential for both the maintenance of pluripotency and neural differentiation, providing mechanistic insight into its function with potential implications for ASD.