Ldb1 mediates trans enhancement in mammals
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA439446 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The monoallelic expression of olfactory receptor (OR) genes is governed by a large number of intergenic enhancer elements that are located in intergenic regions of OR gene clusters. In mature olfactory sensory neurons (OSNs), multiple OR enhancers colocalize in an interchromosomal enhancer hub together with the active OR allele. Here we show that in OSNs OR enhancers are bound by Ldb1, but not general purpose mediators of nuclear architecture (CTCF or the cohesin complex subunit Rad21). Conditional deletion of Ldb1 in OSNs results in the dissolution of long range and interchromosomal contacts between OR Enhancers and in pervasive reductions in OR gene expression.
2018-03-29 | GSE112153 | GEO
Project description:KDM4A mediates maternal zygotic transition in mammals
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Project description:LMO2 is a component of multisubunit DNA-binding transcription factor complexes that regulate gene expression in hematopoietic stem and progenitor cell development. Enforced expression of LMO2 causes leukemia by inducing hematopoietic stem cell-like features in T-cell progenitor cells, but the biochemical mechanisms of LMO2 function have not been fully elucidated. In this study we systematically dissected the LMO2/LDB1 binding interface to investigate the role of this interaction in T-cell leukemia. Alanine scanning mutagenesis of the LIM interaction domain of LDB1 revealed a discrete motif R320LITR required for LMO2 binding. Most strikingly, co-expression of full length, wild type LDB1 increased LMO2 steady state abundance, whereas co-expression of mutant proteins deficient in LMO2 binding compromised LMO2 stability. These mutant LDB1 proteins also exerted dominant negative effects on growth and transcription in diverse leukemic cell lines. Raw gene expression data on HSB-2 cells is presented here.
2015-12-15 | GSE75839 | GEO
Project description:LMO2 is a component of multisubunit DNA-binding transcription factor complexes that regulate gene expression in hematopoietic stem and progenitor cell development. Enforced expression of LMO2 causes leukemia by inducing hematopoietic stem cell-like features in T-cell progenitor cells, but the biochemical mechanisms of LMO2 function have not been fully elucidated. In this study we systematically dissected the LMO2/LDB1 binding interface to investigate the role of this interaction in T-cell leukemia. Alanine scanning mutagenesis of the LIM interaction domain of LDB1 revealed a discrete motif R320LITR required for LMO2 binding. Most strikingly, co-expression of full length, wild type LDB1 increased LMO2 steady state abundance, whereas co-expression of mutant proteins deficient in LMO2 binding compromised LMO2 stability. These mutant LDB1 proteins also exerted dominant negative effects on growth and transcription in diverse leukemic cell lines. Raw gene expression data on HSB-2 cells is presented here. RNAseq were performed on HSB cell lines to examine their expression patterns
2015-12-15 | E-GEOD-75839 | biostudies-arrayexpress
Project description:Carbonic anhydrase 1 (Car1), an early specific marker of the erythroid differentiation, has been used to distinguish fetal and adult erythroid cells since its production closely follows the γ- to β-globin transition, but the molecular mechanism underlying transcriptional regulation of Car1 is unclear. Here, we show that Car1 mRNA decreases significantly when erythroid differentiation is induced in MEL cells. The Ldb1 protein complex including GATA1/SCL/LMO2 binds to the Car1 promoter in uninduced cells and reduced enrichment of the complex during differentiation correlates with loss of Car1 expression. Knockdown of Ldb1 results in a reduction of Ser2 phosphorylated RNA Pol II and Cdk9 at the Car1 promoter region, suggesting that Ldb1 is required for recruitment of Pol II as well as the transcription regulator P-TEFb to enhance elongation of Car1 transcripts. Taken together, these data show that Ldb1 forms a regulatory complex to maintain Car1 expression in erythroid cells. Expression analysis of induced and uninduced MEL cells after control or Ldb1 shRNA knockdown.
2012-12-11 | E-GEOD-42839 | biostudies-arrayexpress
Project description:Many questions remain about how close association of genes and distant enhancers occurs and how this is linked to transcription activation. In erythroid cells, LDB1 is recruited to the β-globin locus via LMO2 and is required for looping of the β-globin locus control region (LCR) to the active β-globin promoter. We show that the LDB1 dimerization domain (DD) is necessary and, when fused to LMO2 is sufficient, to completely restore LCR-promoter looping and transcription in LDB1 depleted cells. The looping function of the DD is unique and irreplaceable by heterologous dimerization domains. Dissection of the DD revealed distinct functional properties of conserved subdomains. Notably, a conserved helical region (DD4/5) is dispensable for LDB1 dimerization and chromatin looping but essential for transcriptional activation. DD4/5 is required for the recruitment of the co-regulators FOG1 and NuRD complex. Lack of DD4/5 alters histone acetylation and RNA polymerase II recruitment and results in failure of the locus to migrate to the nuclear interior as normally occurs during erythroid maturation. These results uncouple enhancer-promoter looping from nuclear migration and transcription activation and reveal new roles for LDB1in these processes. RNA-seq in LDB1 knockdown, LDB1 delta4/5 construct, LDB1 full-length construct, and control in induced MEL cells; three replicates each.
2014-07-02 | E-GEOD-54549 | biostudies-arrayexpress
Project description:We used ChIP-Seq to map Ldb1, Scl and Gata1 binding sites in mouse total bone marrow cells. Together with functional studies comparing gene expression in Murine Erythroleukemia (MEL) cells expressing Ldb1 shRNA or control shRNA and bioinformatics analysis, we systematically determined the transcriptional program controlled by Ldb1 complexes in erythropoiesis. This represents the ChIP-Seq component of the study only
2013-04-29 | GSE42843 | GEO
Project description:The first site exhibiting hematopoietic activity in mammalian development is the yolk sac blood island, which originates from the hemangioblast. Here we performed differentiation assays, as well as genome-wide molecular and functional studies in BL-CFCs to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. We show that the previously reported lack of yolk sac hematopoiesis and vascular development in Ldb1-/- mouse result from a decreased number of hemangioblasts and a block in their ability to differentiate into erythroid and endothelial progenitor cells. Transcriptome analysis and correlation with the genome wide binding pattern of Ldb1 in hemangioblasts revealed a number of direct target genes and pathways misregulated in the absence of Ldb1. The regulation of essential developmental factors by Ldb1 defines it as an upstream transcriptional regulator of hematopoietic/endothelial development. We show the complex interplay that exists between transcription factors and signaling pathways during the very early stages of hematopoietic/endothelial development and the specific signalling occurring in hemangioblasts in contrast to more advanced hematopoietic developmental stages. Finally, by revealing novel genes and pathways, not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells. We used microarrays to detail the global programme of gene expression underlying the Ldb1+/+ and Ldb1-/- in Flk1+ cells. RNA was isolated from Ldb1+/+ and Ldb1-/- Flk1+ cells with the QIAGEN RNeasy Mini Kit and integrity was checked on the Agilent 2100 Bioanalyzer. RNA was converted to biotin-labelled cRNA, hybridised on the Mouse Genome 430 2.0 Array and analyzed with the Affymetrix GeneChip® Scanner 3000 according to the manufacturer protocol.
2013-02-09 | E-GEOD-43042 | biostudies-arrayexpress
Project description:The first site exhibiting hematopoietic activity in mammalian development is the yolk sac blood island, which originates from the hemangioblast. Here we performed differentiation assays, as well as genome-wide molecular and functional studies in BL-CFCs to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. We show that the previously reported lack of yolk sac hematopoiesis and vascular development in Ldb1-/- mouse result from a decreased number of hemangioblasts and a block in their ability to differentiate into erythroid and endothelial progenitor cells. Transcriptome analysis and correlation with the genome wide binding pattern of Ldb1 in hemangioblasts revealed a number of direct target genes and pathways misregulated in the absence of Ldb1. The regulation of essential developmental factors by Ldb1 defines it as an upstream transcriptional regulator of hematopoietic/endothelial development. We show the complex interplay that exists between transcription factors and signaling pathways during the very early stages of hematopoietic/endothelial development and the specific signalling occurring in hemangioblasts in contrast to more advanced hematopoietic developmental stages. Finally, by revealing novel genes and pathways, not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells. Examination of endogenous Ldb1 genome-wide binding sites comparsion between ChIP and Control on Flk1+ BL-CFCs RNA was isolated from Ldb1+/+ and Ldb1-/- Flk1+ cells with the QIAGEN RNeasy Mini Kit and integrity was checked on the Agilent 2100 Bioanalyzer. RNA sequencing was performed on Illumina HiSeq 2000 platform according to the manufacturer instructions.
2013-02-09 | E-GEOD-43041 | biostudies-arrayexpress
Project description:Substantial evidence supports the hypothesis that enhancers are critical regulators of cell type determination, orchestrating both positive and negative transcriptional programs; however, the basic mechanisms by which enhancers orchestrate interactions with cognate promoters during activation and repression events remain incompletely understood. Here we report the required actions of the LIM domain binding protein, LDB1/CLIM2/NLI, interacting with the enhancer binding protein, ASCL1, to mediate looping to target gene promoters and target gene regulation in corticotrope cells. LDB1-mediated enhancer:promoter looping appears to be required for both activation and repression of these target target gene promoter genes. While LDB1-dependend activated genes are regulated at the level of transcriptional initiation, the LDB1-dependent repressed transcription units appear to be regulated primarily at the level of promoter pausing, with LDB1 regulating recruitment of MTA2, a component of the NuRD complex, on these negative enhancers, required for the repressive enhancer function. These results indicate that LDB1-dependent looping events can deliver repressive cargo to cognate promoters to mediate promoter pausing events in a pituitary cell type.
2015-02-03 | GSE64515 | GEO