Project description:MLL3 inactivation mutations occurs frequently in human breast cancer. To understand the function of MLL3 inactivation, we compared the gene expression profiles of the vector control (WT) and Mll3-knockout MCF7 cells generated by CRISPR-CAS9. Affymetrix human Gene 2.0ST arrays were used for microarray.
Project description:To determine the effect of Mll3 deletion on H3K4me3 Chip signals in intestinal stem cell populations. This data has been described in the following article : Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin. Boles MK et al PLoS Genet. 2009 Dec;5(12) and its further analysis can be freely submitted for publication. For information on the proper use of data shared by the Wellcome Trust Sanger Institute (including information on acknowledgement), please see http://www.sanger.ac.uk/datasharing/ Abstract: Briefly we wanted to determine the effect of Mll3 deletion on H3K4me3 binding in cells of the intestine and to compare these to the H3K4me3 pattern found in wildtype animals.
Project description:MLL3 inactivation mutations occurs frequently in human breast cancer. To understand the function of MLL3 inactivation, we compared the gene expression profiles of the vector control (WT) and Mll3-null mouse mammary stem cells generated by CRISPR. Affymetrix mouse Gene 2.0ST ships were used for microarray.
Project description:CDK4/6 inhibitor, abemaciclib induced cell cycle arrest and senescence in breast cancer. We reported that deletion of TP53 prevented the senescence features. In this study, we knockout TP53 by CRISPR Cas9 system and treated MCF7 cells and p53 knockout cells with abemaciclib for up to 29 days to identify the difference of senescence associated secretary phenotype genes and cell cycle related genes. features.
Project description:CDK4/6 inhibitor, abemaciclib induced cell cycle arrest and senescence in breast cancer. We reported that deletion of TP53 prevented the senescence features. In this study, we knockout TP53 by CRISPR Cas9 system and treated MCF7 cells and p53 knockout cells with abemaciclib for up to 29 days to identify the difference of senescence associated secretary phenotype genes and cell cycle related genes. features.
Project description:Enhancers play a key role in regulating cell type-specific gene expression and are marked by histone modifications such as methylation and acetylation. Mono-methylation of lysine 4 on histone H3 (H3K4me1) initially primes enhancers, preceding enhancer activation via acetylation of lysine 27 on histone H3 (H3K27ac). MLL4 is a major enhancer H3K4 mono-methyltransferase with partial functional redundancy with MLL3. However, how H3K4me1 affects enhancer regulation in cell differentiation has remained unclear. By screening several lysine-to-methionine mutants of H3.3, we first found that depletion of H3K4 methylation by H3.3K4M mutation severely impairs adipogenesis in culture. Using tissue-specific expression of H3.3K4M in mice, we further demonstrate that H3.3K4M inhibits adipose tissue and muscle development in vivo. Mechanistically, H3.3K4M destabilizes MLL3/4 proteins but not other members of the mammalian Set1-like H3K4 methyltransferase family and prevents MLL3/4-mediated enhancer activation in adipogenesis. Using tissue-specific deletion of the enzymatic SET domain of MLL3/4 in mice, we also show that deletion of the SET domain prevents adipose tissue and muscle development in vivo and inhibits adipogenesis by destabilizing MLL3/4 in vitro. Notably, H3.3K4M expression mimics MLL3/4 SET domain deletion in preventing adipogenesis. Interestingly, H3.3K4M does not affect adipose tissue maintenance and function, suggesting that MLL3/4-mediated H3K4 methylation is dispensable for the maintenance and function of differentiated adipocytes. Together, our findings suggest that H3.3K4M targets MLL3/4 to prevent enhancer activation in adipogenesis.
Project description:FOXA1 is a pioneer factor that is important in hormone dependent cancer cells to stabilise nuclear receptors, such as estrogen receptor (ER) to chromatin. FOXA1 binds to enhancers regions that are enriched in H3K4mono- and dimethylation (H3K4me1, H3K4me2) histone marks and evidence suggests that these marks are requisite events for FOXA1 to associate with enhancers to initate subsequent gene expression events. However, exogenous expression of FOXA1 has been shown to induce H3K4me1 and H3K4me2 signal at enhancer elements and the order of events and the functional importance of these events is not clear. We performed a FOXA1 Rapid Immunoprecipitation Mass Spectrometry of Endogenous Proteins (RIME) screen in ERα-positive MCF-7 breast cancer cells in order to identify FOXA1 interacting partners and we found histone-lysine N-methyltransferase (MLL3) as the top FOXA1 interacting protein. MLL3 is typically thought to induce H3K4me3 at promoter regions, but recent findings suggest it may contribute to H3K4me1 deposition, in line with our observation that MLL3 associates with an enhancer specific protein. We performed MLL3 ChIP-seq in breast cancer cells and unexpectedly found that MLL3 binds mostly at non-promoter regions enhancers, in contrast to the prevailing hypothesis. MLL3 was shown to occupy regions marked by FOXA1 occupancy and as expected, H3K4me1 and H3K4me2. MLL3 binding was dependent on FOXA1, indicating that FOXA1 recruits MLL3 to chromatin. Motif analysis and subsequent genomic mapping revealed a role for Grainy head like protein-2 (GRHL2) which was shown to co-occupy regions of the chromatin with MLL3. Regions occupied by all three factors, namely FOXA1, MLL3 and GRHL2, were most enriched in H3K4me1. MLL3 silencing decreased H3K4me1 at enhancer elements, but had no appreciable impact on H3K4me3 at enhancer elements. We identify a complex relationship between FOXA1, MLL3 and H3K4me1 at enhancers in breast cancer and propose a mechanism whereby the pioneer factor FOXA1 can interact with a chromatin modifier MLL3, recruiting it to chromatin to facilitate the deposition of H3K4me1 histone marks, subsequently demarcating active enhancer elements.