The nuclear matrix associating protein HNRNPU functions as a key regulator of 3D genome architecture [RNA-Seq]
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ABSTRACT: Higher-order chromatin conformation plays critical role in regulating gene expression and biological development, here we show that HNRNPU, a nuclear matrix attachment factor, is a regulator of 3D genome architecture at multiple levels in mouse hepatocytes. We demonstrate that depletion of HNRNPU results into a global reorganization of nuclear bodies and re-localization of chromatin towards nuclear periphery. Additionally, upon HNRNPU depletion, chromatin interactions between A-type (active) and B-type (inactive) compartments increase significantly but those among same types of compartments decrease significantly, which associate with global gene expression changes. While TADs remain largely invariant, both inter- and intra-TAD interactions increase significantly in A-type compartments but decrease in B-type compartments. Mechanically, HNRNPU complexes with structural proteins CTCF and RAD21; depletion of HNRNPU specifically weakens the bindings of RAD21 to the chromatin, which is highly correlated with the weakness of chromatin loops.
Project description:Higher-order chromatin conformation plays critical role in regulating gene expression and biological development, here we show that HNRNPU, a nuclear matrix attachment factor, is a regulator of 3D genome architecture at multiple levels in mouse hepatocytes. We demonstrate that depletion of HNRNPU results into a global reorganization of nuclear bodies and re-localization of chromatin towards nuclear periphery. Additionally, upon HNRNPU depletion, chromatin interactions between A-type (active) and B-type (inactive) compartments increase significantly but those among same types of compartments decrease significantly, which associate with global gene expression changes. While TADs remain largely invariant, both inter- and intra-TAD interactions increase significantly in A-type compartments but decrease in B-type compartments. Mechanically, HNRNPU complexes with structural proteins CTCF and RAD21; depletion of HNRNPU specifically weakens the bindings of RAD21 to the chromatin, which is highly correlated with the weakness of chromatin loops.
Project description:Higher-order chromatin conformation plays critical role in regulating gene expression and biological development, here we show that HNRNPU, a nuclear matrix attachment factor, is a regulator of 3D genome architecture at multiple levels in mouse hepatocytes. We demonstrate that depletion of HNRNPU results into a global reorganization of nuclear bodies and re-localization of chromatin towards nuclear periphery. Additionally, upon HNRNPU depletion, chromatin interactions between A-type (active) and B-type (inactive) compartments increase significantly but those among same types of compartments decrease significantly, which associate with global gene expression changes. While TADs remain largely invariant, both inter- and intra-TAD interactions increase significantly in A-type compartments but decrease in B-type compartments. Mechanically, HNRNPU complexes with structural proteins CTCF and RAD21; depletion of HNRNPU specifically weakens the bindings of RAD21 to the chromatin, which is highly correlated with the weakness of chromatin loops.
Project description:Higher-order chromatin conformation plays critical role in regulating gene expression and biological development, here we show that HNRNPU, a nuclear matrix attachment factor, is a regulator of 3D genome architecture at multiple levels in mouse hepatocytes. We demonstrate that depletion of HNRNPU results into a global reorganization of nuclear bodies and re-localization of chromatin towards nuclear periphery. Additionally, upon HNRNPU depletion, chromatin interactions between A-type (active) and B-type (inactive) compartments increase significantly but those among same types of compartments decrease significantly, which associate with global gene expression changes. While TADs remain largely invariant, both inter- and intra-TAD interactions increase significantly in A-type compartments but decrease in B-type compartments. Mechanically, HNRNPU complexes with structural proteins CTCF and RAD21; depletion of HNRNPU specifically weakens the bindings of RAD21 to the chromatin, which is highly correlated with the weakness of chromatin loops.
Project description:Here we show that HNRNPU, the major nuclear matrix attachment factor, is necessary to maintain proper nuclear architecture in mouse hepatocytes. Upon HNRNPU depletion, the interactions between chromatin and nuclear lamina have been changed dramatically;chromatin organization is globally changed; boundaries of topologically associating domains (TADs) become weaker; inter-TAD interactions are increased; thousands of genes are significantly altered coincident with 3D chromatin changes. Mechanically, HNRNPU interacts with CTCF and RAD21, which affects the binding of RAD21 to the chromatin significantly, whereas CTCF bindings are almost unchanged, what’ more, the decrease of binding strengths are highly correlated with the weakness of loop bounded by Rad21. Taken together, we identify HNRNPU as a key regulator of chromatin architecture, and our data suggest the importance of nuclear matrix associating factors in 3D genome organization.
Project description:The nuclei of eukaryotes contain various higher-order chromatin architectures and nuclear bodies (NBs), which are critical for proper nuclear functions. By using mouse hepatocytes as the model, we knocked-down SRRM2, a core protein component scaffolding NSs, and performed Hi-C experiments to examine genome-wide chromatin interactions. We found that Srrm2 depletion disrupted the NSs and changes expression of about 1,000 genes. The intra-chromosomal interactions were decreased in type A (active) compartments and increased in type B (repressive) compartments. Furthermore, upon Srrm2 knockdown, the insulation of TADs was decreased specifically in active compartments, and the most significant reduction was found in the A1 sub-compartments. We showed that disruption of NSs by Srrm2 knockdown led to a global decrease of chromatin interactions in active compartments, indicating critical functions of NSs in the organization of the 3D genome.
Project description:The nuclei of eukaryotes contain various higher-order chromatin architectures and nuclear bodies (NBs), which are critical for proper nuclear functions. By using mouse hepatocytes as the model, we knocked-down SRRM2, a core protein component scaffolding NSs, and performed Hi-C experiments to examine genome-wide chromatin interactions. We found that Srrm2 depletion disrupted the NSs and changes expression of about 1,000 genes. The intra-chromosomal interactions were decreased in type A (active) compartments and increased in type B (repressive) compartments. Furthermore, upon Srrm2 knockdown, the insulation of TADs was decreased specifically in active compartments, and the most significant reduction was found in the A1 sub-compartments. We showed that disruption of NSs by Srrm2 knockdown led to a global decrease of chromatin interactions in active compartments, indicating critical functions of NSs in the organization of the 3D genome.
Project description:In eukaryotes, the nuclear chromatin in the interphase is a hierarchical organization. Previous studies have suggested that cohesin-DNA interactions play important architectural functions for chromatin structure in the interphase. In this study, we applied super-resolution imaging, single-molecule imaging to measure the distribution of cohesin subunits. Hi-C and RNA-seq were used to reveal the 3D genome structures alterations and the relationship with breast cancer upon Rad21 up-regulation. Hi-C experiment showed that the contact frequency of short distance was increased while that of long distance was decreased in the absence of Rad21 up-regulation. Chromatin interactions between A and B compartments increased and compartmentalization strength was reduced significantly upon Rad21 up-regulation. Correspondingly, accumulated contacts were shown at TAD corners and inter-TAD interactions increased. These observations support cohesin loop extrusion model and lead us to propose the unique role of Rad21-loader interaction in cohesin loading and further cohesin extrusion. Moreover, we combined transcriptome changes and chromatin structure alterations upon Rad21 up-regulation and revealed the correlation between Rad21 and breast cancer by affecting chromatin architecture.
Project description:Genetic variants affecting Heterogeneous Nuclear Ribonucleoprotein U (HNRNPU) have been identified in several neurodevelopmental disorders (NDDs). HNRNPU is widely expressed in the human brain and shows the highest postnatal expression in the cerebellum. Recent studies have investigated the role of HNRNPU in cerebral cortical development, but the effects of HNRNPU deficiency on cerebellar development remain unknown. Here, we describe the molecular and cellular outcomes of HNRNPU locus deficiency during in vitro neural differentiation of patient-derived and isogenic neuroepithelial stem cells with a hindbrain profile. We demonstrate that HNRNPU deficiency leads to chromatin remodeling of A/B compartments, and transcriptional rewiring, partly by impacting exon inclusion during mRNA processing. Genomic regions affected by the chromatin restructuring and host genes of exon usage differences show a strong enrichment for genes implicated in epilepsies, intellectual disability, and autism. Lastly, we show that at the cellular level. HNRNPU downregulation leads to altered neurogenesis and an increased fraction of neural progenitors in the maturing neuronal population. We conclude that, HNRNPU locus is involved in delayed commitment of neural progenitors to neuronal maturation in cell types with hindbrain profile.
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.