Project description:MBD5 can physically interact with BAP1. Some genes may be regulated by both MBD5 and BAP1. We used microarrays to check whether the overlaps of differentially expressed genes when knockdown MBD5 or BAP1 were more than that would be expected by chance. Thus, we could suggest that BAP1 was required for the regulatory effect of MBD5
Project description:The BRCA1-associated protein 1 (BAP1) is a ubiquitin carboxy-terminal hydrolase (UCH), which forms a multi-protein complex with different epigenetic factors such as ASXL1-3, and FOXK1/2. At chromatin, BAP1 catalyzes the removal of mono-ubiquitination on histone H2AK119 in collaboration with other subunits within the complex, and therefore functions as a transcriptional activator. However, the crosstalk between different subunits and how these subunits impact BAP1 function remains unclear. Here, we report the identification of the methyl-CpG-binding domain proteins 5 and 6 (MBD5 and MBD6) that bind to the C-terminal PHD fingers of the large scaffold subunits ASXL1-3 and stabilize the BAP1 complex at chromatin. We further identified a previously uncharacterized Drosophila protein, the six-banded (SBA), as the ortholog of human MBD5/6. We demonstrated the core module of the BAP1 complex is structurally and functionally conserved during the evolution from Drosophila (Calypso/ASX/SBA) to human cells (BAP1/ASXL/MBD). Dysfunction of the BAP1 complex induced by the misregulation/mutations in each subunit is frequent in human cancer. In BAP1-dependent human cancers, MBD6 tends to be a dominant form. Depletion of MBD6 leads to a global loss of BAP1 occupancy at chromatin, resulting in a reduction of BAP1-dependent gene expression and tumor growth in vitro and in vivo. In summary, our study has uncovered MBD5/6 as important regulators of the BAP1 complex and transcription, and sheds light on the therapeutic potential of targeting MBD5/6 in human cancer.
Project description:Analysis of the effect that reduced BAP1 levels have on global gene expression.The hypothesis tested was that reduction in BAP1 levels would produce changes in gene expression similar to changes observed in class 2 uveal melanomas. Data provided insight into genes that are disrupted with reduced BAP1 levels. Total RNA was isolated from 92.1 cells transfected with either control or BAP1 knockdown constructs for global expression analysis.
Project description:Background: MBD5, encoding the methyl-CpG-binding domain 5 protein, has been proposed as a necessary and sufficient driver of the 2q23.1 microdeletion syndrome. De novo missense and protein-truncating variants from exome sequencing studies have directly implicated MBD5 in the etiology of autism spectrum disorder (ASD) and related neurodevelopmental disorders (NDDs). However, little is known concerning the specific function(s) of MBD5. Methods: In an effort to gain insight into the complex interactions associated with genetic alteration of MBD5 in individuals with ASD and related NDDs, we explored the transcriptional landscape of MBD5 haploinsufficiency across multiple mouse brain regions of the heterozygous hypomorphic Mbd5+/GT mouse model and compared these results to CRISPR-mediated mutations of MBD5 in human iPSC-derived neuronal models. Results: Gene expression analyses of three brain regions from Mbd5+/GT mice showed cortex as the region most affected by the knockdown, indicating context-dependent effects. Gene co-expression network analyses revealed gene clusters that are associated with MBD5 knockdown and enriched for GPCR signaling and terms related to ciliary function. We also identified genes that were downregulated in both models such as EPHA3, OLIG1, related to neuronal development and glial function. Limitations: These analyses were performed in a limited number of brain regions and neuronal models, and the effects of the gene knockdown are subtle. As such, these results will not reflect the full extent of MBD5 disruption across brain tissues during early brain developmentneurodevelopment in ASD. Conclusions: Our study points to transcriptional consequences of Mbd5 disruption in the brain and suggests a link between MBD5 and pathways such as ciliary function that are associated with established developmental disorders and syndromes.
Project description:Background: MBD5, encoding the methyl-CpG-binding domain 5 protein, has been proposed as a necessary and sufficient driver of the 2q23.1 microdeletion syndrome. De novo missense and protein-truncating variants from exome sequencing studies have directly implicated MBD5 in the etiology of autism spectrum disorder (ASD) and related neurodevelopmental disorders (NDDs). However, little is known concerning the specific function(s) of MBD5. Methods: In an effort to gain insight into the complex interactions associated with genetic alteration of MBD5 in individuals with ASD and related NDDs, we explored the transcriptional landscape of MBD5 haploinsufficiency across multiple mouse brain regions of the heterozygous hypomorphic Mbd5+/GT mouse model and compared these results to CRISPR-mediated mutations of MBD5 in human iPSC-derived neuronal models. Results: Gene expression analyses of three brain regions from Mbd5+/GT mice showed cortex as the region most affected by the knockdown, indicating context-dependent effects. Gene co-expression network analyses revealed gene clusters that are associated with MBD5 knockdown and enriched for GPCR signaling and terms related to ciliary function. We also identified genes that were downregulated in both models such as EPHA3, OLIG1, related to neuronal development and glial function. Limitations: These analyses were performed in a limited number of brain regions and neuronal models, and the effects of the gene knockdown are subtle. As such, these results will not reflect the full extent of MBD5 disruption across brain tissues during early brain developmentneurodevelopment in ASD. Conclusions: Our study points to transcriptional consequences of Mbd5 disruption in the brain and suggests a link between MBD5 and pathways such as ciliary function that are associated with established developmental disorders and syndromes.
Project description:The deubiquitinase BAP1 is a candidate tumor suppressor regulating cell proliferation in human and is required for development in Drosophila. BAP1 is assembled into high molecular weight transcriptional multi-protein complexes. In order to identify potential BAP1 target genes, global mRNA expression profiling using microarrays was conducted. U2OS cells, transfected with a non-target control shRNA or shRNAs targeting BAP1, were selected with puromycin containing medium and then synchronized at the G1/S border to allow comparative analysis of gene expression.
Project description:Analysis of the effect that reduced BAP1 levels have on global gene expression.The hypothesis tested was that reduction in BAP1 levels would produce changes in gene expression similar to changes observed in class 2 uveal melanomas. Data provided insight into genes that are disrupted with reduced BAP1 levels.
Project description:The deubiquitinase BAP1 is a candidate tumor suppressor regulating cell proliferation in human and is required for development in Drosophila. BAP1 is assembled into high molecular weight transcriptional multi-protein complexes. In order to identify potential BAP1 target genes, global mRNA expression profiling using microarrays was conducted.
Project description:Epilepsy is considered to result from an imbalance between excitation and inhibition of the central nervous system. Pathogenic mutations in the methyl-CpG binding domain protein 5 gene (MBD5) are known to cause epilepsy. However, the function and mechanism of MBD5 in epilepsy remain elusive. Here, we found that MBD5 was mainly localized in the pyramidal cells and granular cells of mouse hippocampus, and its expression was increased in the brain tissues of mouse models of epilepsy. Exogenous overexpression of MBD5 inhibited the transcription of the signal transducer and activator of transcription 1 gene (Stat1), resulting in increased expression of N-methyl-D-aspartate receptor (NMDAR) subunit 1 (GluN1), 2A (GluN2A) and 2B (GluN2B), leading to aggravation of the epileptic behaviour phenotype in mice. In contrast, overexpression of STAT1 reduced the expression of NMDARs and alleviated the epileptic behavioural phenotype of mice. Furthermore, the epileptic behavioural phenotype was relieved by the NMDAR antagonist memantine. These results indicate that MBD5 accumulation affects seizures through STAT1-mediated inhibition of NMDAR expression in mice. Collectively, our findings suggest that the MBD5-STAT1- NMDAR pathway may be a new pathway that regulates the epileptic behavioural phenotype and may represent a new treatment target.