Project description:Purpose: The goals of this study are to investigate the molecular mechanism by which MEIS2 controls HEP specification and EHT through compareing the mRNA profiling of Wild Type and MEIS2 deleted H1 drived cells at day4 of hematopoietic differentiation. Methods: mRNA profiles of Wild Type and MEIS2 deleted H1 drived cells at day4 of hematopoietic differentiation were generated by deep sequencing using Illumina GAIIx. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Conclusions:a large number of genes were down-regulated in MEIS2-deleted H1 hESCs when compared with the wild-type cells. Among those, a number of mammalian hematopoiesis-associated genes such as TAL1 ,GFI and GATA2 were significantly down-regulated.
Project description:Purpose: The goals of this study are to investigate the molecular mechanism by which MEIS1 controls megakaryocytic maturation and thrombopoiesis through compareing the mRNA profiling of Wild Type and MEIS1 deleted H1 drived cells at day6 of megakaryocytic differentiation.
Project description:Purpose: The goals of this study are to investigate the molecular mechanism by which MEIS1 controls HEP specification through compareing the mRNA profiling of Wild Type and MEIS1 deleted H1 drived cells at day3 of hematopoietic differentiation. Conclusions:a large number of genes were down-regulated in MEIS1-deleted H1 hESCs when compared with the wild-type cells. Among those, a number of mammalian hematopoiesis-associated genes such as FLI1, APLN, TAL1 and MYB were significantly down-regulated.
Project description:Here we adopt ChOR-seq (Chromatin Occupancy after Replication) to monitor the dynamic re-establishment of H3K27me3 on nascent DNA during DNA replication. We found that the linker histone H1 facilitates the rapid post-replication restoration of H3K27me3 on repressive genes, which is essential for maintaining gene silencing and cell identity during cell division. Interestingly, the restoration rate of H3K27me3 on nascent DNA is greatly compromised after depletion of H1c/d/e. Finally, our in vitro biochemical experiments demonstrate that H1 facilitates the propagation of H3K27me3 by PRC2 through compacting chromatin. Collectively, our results indicate that H1-mediated chromatin compaction facilitates the propagation and restoration of H3K27me3 after DNA replication, which is key to cell fate determination.
Project description:Calpains are non-lysosomal, Ca2+-dependent cysteine proteases, which are associated with various cellular functions but have so far been mainly studied in the context of disease. Their contribution to homeostasis in the healthy organism is still not well understood and their substrates have remained enigmatic in most cases. In the present study, we describe a previously unrecognized role for the calpain protease calpain2 in the regulation of neuronal differentiation of adult neural stem- and progenitor cells through cleavage and elimintation of the neuronal fate determinant MEIS2. Mass spectrometry analysis was performed on immunoprecipitated MEIS2 protein to identify phosphory¬lated residues in MEIS2 and on immunoprecipitated MEIS2 incubated with native porcine calpain2 to map calpain2-induced cleavage sites in the protein.
Project description:ChIP-Sequencing on Meis2-HA in E12.5 palate, to identify Meis2 binding chromatin regions and target genes. Haploinsufficiency of MEIS2 is associated with cleft palate in humans and Meis2 inactivation leads to abnormal palate development in mice, implicating an essential role for Meis2 in palate development. However, its functional mechanisms remain unknown. In this study, we found widespread Meis2 expression in the developing palate in mice. Meis2 inactivation by Wnt1Cre in cranial neural crest cells led to the cleft of the secondary palate. Importantly, about half of Wnt1Cre;Meis2f/f mice exhibited submucous cleft, providing an excellent model for studying palatal bone formation and patterning. Consistent with a complete absence of the palatal bones, integrative analyses of Meis2 ChIP-seq, RNA-seq, and ATAC-seq results identified key osteogenic genes that are regulated directly by Meis2, indicating the fundamental role of Meis2 in palatal osteogenesis. De novo motif analysis discovered that the Meis2-bound regions possess highly enriched binding motifs of several key osteogenic transcription factors particularly Shox2. Comparison of Meis2 and Shox2 ChIP-seq analyses further revealed a genome-wide co-occupancy, in addition to their co-localization in the developing palate and physical interaction, suggesting that Shox2 and Meis2 act as partners. However, while Shox2 is required for proper palatal bone formation and is a direct downstream target of Meis2, Shox2 overexpression failed to rescue the palatal bone defects in Meis2 mutant background. These results, together with the facts that Meis2 expression is associated with high osteogenic potential and is required for the chromatin accessibility of osteogenic genes, support a vital function of Meis2 in setting up the ground state for palatal osteogenesis.
Project description:The homeodomain protein Meis1 is essential for definitive hematopoiesis and vascular patterning in the mouse embryo. Meis2, another member of the same family, shares 82% protein identities with Meis1. Our present study suggested Meis2 exerts two distinguishable effects in differentiating ES cells. First, it increases the numbers of hematopoietic progenitors and extends their persistence in culture. Second, Meis2 skews hematopoietic differentiation by suppressing erythroid while enhancing megakaryocytic progenitor differentiation. To identify the underlying transcriptional bases of these actions, we carried out microarray analysis to compare the various populations of cells developing in ES differentiation cultures in the presence and absence of Meis2 induction. ES cells with dox-inducible Meis2 (A2lox.Meis2) were differentiated as embryoid bodies (EBs) for 6 days before plating on OP9-GFP cell monolayers and cytokines, and treated with (+) or without (-) doxycycline (dox). Cells were purified by cell sorting on day 7 or 8 into various populations based on levels of CD41 expression: GFP-CD41-, GFP-CD41+ (day 7) and GFP-CD41-,GFP-CD41int, and GFP-CD41hi (day 8). Gene expression of these purified populations was determined by microarray analysis.
Project description:The homeodomain protein Meis1 is essential for definitive hematopoiesis and vascular patterning in the mouse embryo. Meis2, another member of the same family, shares 82% protein identities with Meis1. Our present study suggested Meis2 exerts two distinguishable effects in differentiating ES cells. First, it increases the numbers of hematopoietic progenitors and extends their persistence in culture. Second, Meis2 skews hematopoietic differentiation by suppressing erythroid while enhancing megakaryocytic progenitor differentiation. To identify the underlying transcriptional bases of these actions, we carried out microarray analysis to compare the various populations of cells developing in ES differentiation cultures in the presence and absence of Meis2 induction.
Project description:We use RNA-sequencing to profile the different expression genes in the palatal mesenchyme of wildtype and Wnt1Cre;Meis2f/f mice at E12.5. Haploinsufficiency of MEIS2 is associated with cleft palate in humans and Meis2 inactivation leads to abnormal palate development in mice, implicating an essential role for Meis2 in palate development. However, its functional mechanisms remain unknown. In this study, we found widespread Meis2 expression in the developing palate in mice. Meis2 inactivation by Wnt1Cre in cranial neural crest cells led to the cleft of the secondary palate. Importantly, about half of Wnt1Cre;Meis2f/f mice exhibited submucous cleft, providing an excellent model for studying palatal bone formation and patterning. Consistent with a complete absence of the palatal bones, integrative analyses of Meis2 ChIP-seq, RNA-seq, and ATAC-seq results identified key osteogenic genes that are regulated directly by Meis2, indicating the fundamental role of Meis2 in palatal osteogenesis. De novo motif analysis discovered that the Meis2-bound regions possess highly enriched binding motifs of several key osteogenic transcription factors particularly Shox2. Comparison of Meis2 and Shox2 ChIP-seq analyses further revealed a genome-wide co-occupancy, in addition to their co-localization in the developing palate and physical interaction, suggesting that Shox2 and Meis2 act as partners. However, while Shox2 is required for proper palatal bone formation and is a direct downstream target of Meis2, Shox2 overexpression failed to rescue the palatal bone defects in Meis2 mutant background. These results, together with the facts that Meis2 expression is associated with high osteogenic potential and is required for the chromatin accessibility of osteogenic genes, support a vital function of Meis2 in setting up the ground state for palatal osteogenesis.
Project description:MEIS2 has an important role in development and organogenesis, and is implicated in the pathogenesis of human cancer. The molecular basis of MEIS2 action in tumorigenesis is not clear. Here, we show that MEIS2 is highly expressed in human neuroblastoma cell lines and is required for neuroblastoma cell survival and proliferation. Depletion of MEIS2 in neuroblastoma cells leads to M phase arrest and mitotic catastrophe, whereas ectopic expression of MEIS2 markedly enhances neuroblastoma cell proliferation, anchorage-independent growth, and tumorigenicity. Gene expression profiling reveals an essential role of MEIS2 in maintaining the expression of a large number of late cell cycle genes, including those required for DNA replication, G2-M checkpoint control and M phase progression. Importantly, we identify MEIS2 as a transcription activator of the MuvB-BMYB-FOXM1 complex that functions as a master regulator of mitotic gene expression. Further, we show that FOXM1 is a direct target gene of MEIS2 and is required for MEIS2 to upregulate mitotic genes. These findings link a development gene to the control of cell cycle progression and suggest that high MEIS2 expression is a molecular mechanism for high expression of mitotic genes that is commonly observed in cancers of poor prognosis. Affymetrix microarray assays were performed according to the manufacturer's directions on total RNA isolated from three independent samples of BE(2)-C cells infected with lentiviruses expressing either shGFP or shMEIS2-43 for 48 hours.