The development of affinity purification technologies together with mass spectrometric analyses of the purified protein mixtures (AP-MS) has been used both to identify new protein-protein interactions and to define the subunit composition of protein complexes. Transcription factor protein interactions, however, have not been systematically analyzed using these approaches. Here, we have investigated whether ectopic expression of an affinity tagged transcription factor as bait in AP-MS experiments perturbs gene expression in cells resulting in false positive identification of bait associated proteins when typical experimental controls are used. Using quantitative proteomics and RNA-Seq, we determined that the increase in the abundance of a set of proteins caused by overexpression of the transcription factor RelA is not sufficient for these proteins to then copurify non-specifically and be misidentified as bait associated proteins. Therefore typical controls should be sufficient and a number of different baits can be compared with a common set of controls. This is of practical interest when identifying bait interactors from a large number of different baits. As expected, we found several known RelA interactors enriched in our RelA purifications (NFêB1, NFêB2, Rel, RelB, IêBá, IêBâ and IêBå). We also found several proteins not previously described in association with RelA, including the small mitochondrial chaperone Tim13. Using a variety of biochemical approaches, we further investigated the nature of the association between Tim13 and NFêB family transcription factors. The work here therefore provides a conceptual and experimental framework for analyzing transcription faction protein interactions. Overall design: Gene expression profiles were assayed in triplicate from HEK293 cells expressing either Halo-RelA, Halo-NFkB1, or Halo tag alone.
Controlling for gene expression changes in transcription factor protein networks.
No sample metadata fields
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Transcription factor and microRNA interactions in lung cells: an inhibitory link between NK2 homeobox 1, miR-200c and the developmental and oncogenic factors Nfib and Myb.
Cell line, Treatment
View SamplesCell-specific gene expression is achieved by a combination of mechanisms including transcriptional and post-transcriptional regulation. The transcription factor Nkx2-1, essential for lung cell differentiation, mainly acts in transcriptional activation but can directly or indirectly repress gene expression. microRNAs are a class of small non-coding RNA that control one of the major mechanisms of gene repression. To identify miRNAs regulated by Nkx2-1 that may mediate its repressing effects, we knocked-down Nkx2-1 in mouse lung epithelial cell lines and systematically identified targets by genome-wide miR and mRNA expression analyses. Nkx2-1 controls expression of miRs known to contribute to lung cell differentiation in development and disease and others not previously described. Amongst the significantly altered miRs, the mir-106a-363 cluster, miR-1195, miR-378, and miR-346 are directly correlated with the levels of Nkx2-1, whereas miR-200c/b, miR-221, and miR- 222 are inversely correlated. These miRNAs are expressed in embryonic lung at day E11.5, and/or E19.5 determined by in-situ hybridization. Expression of predicted targets of mir-1195, mir-346 and miR-200c and mir-221/222 were evaluated by mRNA expression microarrays in Nkx2-1 knockdown cells identifying those anti-correlated to the corresponding miRNA expression. Genes regulated by mir-1195, Cyp2s1 and Map3k2, by mir-346, Klf6, and miR-200c, Myb, Nfib, and Six1, were validated by qRT-PCR. Inhibition of mir-1195 confirms the inverse correlation of this miRNA with its putative targets Cyp2s1 and Map3k2. This miRNA-mRNA expression analysis identifies potential paths of Nkx2-1 mediated gene repression, and contributes to the understanding of gene regulation in lung epithelial differentiation and development.
Transcription factor and microRNA interactions in lung cells: an inhibitory link between NK2 homeobox 1, miR-200c and the developmental and oncogenic factors Nfib and Myb.
Cell line, Treatment
View SamplesThe Saccharomyces cerevisiae R2TP protein complex consists of Rvb1, Rvb2, Pih1 and Tah1. The R2TP complex has been implicated in various cellular processes such as assembly of snoRNP complex, RNA polymerase II complex, apoptosis and PIKK signaling. The involvement of R2TP in assembling various complexes seems to be in part due to Pih1 and Tah1, which serve as adapter/recruiter proteins. Here, we have performed high resolution RNA-seq. analyses to identify differential expression levels between wild type and PIH1 and TAH1 deletion strains of Saccharomyces cerevisiae that can help in unraveling other functions of Pih1 and Tah1. Both wild type and deletion strains contained TAP (tandem affinity purification) tag at the C-terminal end of either RVB1 or RVB2. Overall design: 3 biological replicates were performed for each strains
Proteomic and Genomic Analyses of the Rvb1 and Rvb2 Interaction Network upon Deletion of R2TP Complex Components.
Cell line, Subject
View SamplesThe Grainyhead family of transcription factors controls morphogenesis and differentiation of epithelial cell layers in multicellular organisms by regulating cell junction- and proliferation-related genes. Grainyhead-like 2 (Grhl2) is expressed in developing mouse lung epithelium and is required for normal lung organogenesis. The specific epithelial cells expressing Grhl2 and the genes regulated by Grhl2 in normal lungs are mostly unknown. In these studies, we identified the NK2 homeobox 1 transcription factor (Nkx2-1) as a direct transcriptional target of Grhl2. By binding and transcriptional assays, and by confocal microscopy we showed that these two transcription factors form a positive feed-back loop in vivo and in cell lines, and are co-expressed in lung bronchiolar and alveolar type II cells. The morphological changes observed in flattening lung alveolar type II cells in culture are associated with down-regulation of Grhl2 and Nkx2-1. Reduction of Grhl2 in lung epithelial cell lines results in lower expression levels of Nkx2-1 and of known Grhl2 target genes. By microarray analysis we identified that in addition to Cadherin1 and Claudin4, Grhl2 regulates other cell interaction genes such as semaphorins and their receptors, which also play a functional role in developing lung epithelium. Impaired collective cell migration observed in Grhl2 knockdown cell monolayers is associated with reduced expression of these genes and may contribute to the altered epithelial phenotype reported in Grhl2 mutant mice. Thus, Grhl2 functions at the nexus of a novel regulatory network, connecting lung epithelial cell identity, migration and cell-cell interactions.
The transcription factors Grainyhead-like 2 and NK2-homeobox 1 form a regulatory loop that coordinates lung epithelial cell morphogenesis and differentiation.
Cell line
View SamplesAnalysis of different iPSC clones in comparison to parental fibroblasts and Pluripotent ESC and iPSC lines
CD44 is a negative cell surface marker for pluripotent stem cell identification during human fibroblast reprogramming.
Cell line
View SamplesThrough deep sequencing and functional screening in zebrafish, we find that miR-221 is essential for angiogenesis. miR-221 knockdown phenocopied defects associated with loss of the tip cell-expressed Flt4 receptor. Furthermore, miR-221 was required for tip cell proliferation and migration, as well as tip cell potential in mosaic blood vessels. miR-221 knockdown also prevented “hyper-angiogenesis” defects associated with Notch deficiency and miR-221 expression was inhibited by Notch signaling. Finally, miR-221 promoted tip cell behavior through repression of two targets: cyclin-dependent kinase inhibitor 1b (cdkn1b) and phosphoinositide-3-kinase regulatory subunit 1 (pik3r1). These results identify miR-221 as an important regulatory node through which tip cell migration and proliferation are controlled during angiogenesis. Overall design: Identification of endothelial-expressed microRNA from FACS-isolated zebrafish endothelial cells.
miR-221 is required for endothelial tip cell behaviors during vascular development.
No sample metadata fields
View SamplesThe generation of neocortical neurons from neural progenitor cells (NPCs) is primarily controlled by transcription factors binding to DNA in the context of chromatin. To understand the complex layer of regulation that orchestrates different NPC types from the same DNA sequence, epigenome maps with cell type resolution are required. Here we present genome-wide histone methylation maps for distinct neural cell populations in the developing mouse neocortex. Using different chromatin features, we identify potential novel regulators of cortical NPCs available for future exploration. Moreover, we identify extensive H3K27me3 changes between NPC subtypes coinciding with major developmental and cell biological transitions. Interestingly, we detect dynamic H3K27me3 changes on promoters of several crucial transcription factors, including the basal progenitor regulator Eomes. We used catalytically inactive Cas9 fused with the histone methyltransferase Ezh2 to edit H3K27me3 at the Eomes locus in vivo, which results in reduced Tbr2 expression and lower basal progenitor abundance, underscoring the relevance of dynamic H3K27me3 changes during neocortex development. Taken together, we provide a rich resource of neocortical histone methylation and outline an approach to investigate its contribution to the regulation of selected genes during neocortical development. Overall design: Gene expression profile of mouse purified neuroepithelial cells (NECs) was generated by RNA-seq. --------------- This represents the RNA-Seq component only
Epigenome profiling and editing of neocortical progenitor cells during development.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A systems biology approach identifies a regulatory network in parotid acinar cell terminal differentiation.
Specimen part
View SamplesThis study identifies miR-198 as a potential inhibitor of keratinocyte migration in skin
'See-saw' expression of microRNA-198 and FSTL1 from a single transcript in wound healing.
Specimen part, Time
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