Programmable nucleases have enabled rapid and accessible genome engineering in eukaryotic cells and living organisms. However, their delivery into target cells can be technically challenging when working with primary cells or in vivo. Using engineered murine leukemia virus-like particles loaded with Cas9/sgRNA ribonucleoproteins (“Nanoblades”), we were able to induce efficient genome-editing in cell lines and primary cells including human induced pluripotent stem cells, human hematopoietic stem cells and mouse bone-marrow cells. Transgene-free Nanoblades were also capable of in vivo genome-editing in mouse embryos and in the liver of injected mice. Nanoblades can be complexed with donor DNA for “all-in-one” homology-directed repair or programmed with modified Cas9 variants to mediate transcriptional up-regulation of target genes. Nanoblades preparation process is simple, relatively inexpensive and can be easily implemented in any laboratory equipped for cellular biology. Overall design: Virus-like particles were purified on a sucrose cushion. Total RNA was extracted using Trizol and fragmented to ~100 nucleotides and used as input for cDNA library preparation. PCR-amplified libraries were sequenced on the Hiseq2500 platform (Illumina)
Genome editing in primary cells and in vivo using viral-derived Nanoblades loaded with Cas9-sgRNA ribonucleoproteins.
Cell line, Subject
View SamplesStabilin-1/CLEVER-1 is a multidomain protein present in lymphatic and vascular endothelial cells and in M2 immunosuppressive macrophages. Stabilin-1 functions in scavenging, endocytosis and leukocyte adhesion to and transmigration through the endothelial cells. Overall design: The transcriptome of liver tissue in 5wk old Stab1 knock-out mice was compared to that of corresponding wild type mice
Stabilin-1 expression defines a subset of macrophages that mediate tissue homeostasis and prevent fibrosis in chronic liver injury.
Age, Specimen part, Subject
View SamplesBackground. Infections caused by Staphylococcus aureus are associated with significant morbidity and mortality and are an increasing threat not only in hospital settings. The expression of the staphylococcal virulence factor repertoire is known to be affected by the alternative sigma factor B (SigB). However, its impact during infection still is a matter of debate. Methods. Kidney tissue of controls or mice infected with S. aureus HG001 or its isogenic sigB mutant was analyzed by transcriptome profiling to monitor the host response, and additionally expression of selected S. aureus genes was monitored by RT-qPCR. Results. Direct transcript analysis by RT-qPCR revealed significant SigB activity in all mice infected with the wild type strain (WT), but not in its isogenic sigB mutant (p<0.0001). Despite a clear cut difference in the SigB-dependent transcription pattern of virulence genes (clfA, aur, and hla), the host reaction to infection (either WT or sigB mutant) was almost identical. Conclusions. Despite its significant activity in vivo, loss of SigB did not have an effect on the outcome of infection as well as on murine kidney gene expression pattern. Thus, these data support the role of SigB as virulence modulator rather than being a virulence determinant by itself.
The alternative sigma factor B modulates virulence gene expression in a murine Staphylococcus aureus infection model but does not influence kidney gene expression pattern of the host.
Sex, Specimen part
View SamplesUnderstanding how the expression of transcription factor (TF) genes is modulated is essential for reconstructing gene regulatory networks. There is increasing evidence that sequences other than upstream noncoding can contribute to modulating gene expression, but how frequently they do so remains unclear. Here, we investigated the regulation of TFs expressed in a tissue-enriched manner in Arabidopsis roots. For 61 TFs, we created GFP reporter constructs driven by each TF's upstream noncoding sequence (including the 5'UTR) fused to the GFP reporter gene alone or together with the TF's coding sequence. We compared the visually detectable GFP patterns with endogenous mRNA expression patterns, as defined by a genome-wide microarray root expression map.
Transcriptional and posttranscriptional regulation of transcription factor expression in Arabidopsis roots.
Age, Specimen part
View SamplesBET-regulated transcriptome and BRD4, BRD2, BRD3 and Pol II ChIP-seq datasets in human ESCs before and after BET inhibition. Transcription factors and chromatin remodeling complexes are key determinants of embryonic stem cell (ESC) identity. In this study, we investigate the role of BRD4, a member of the bromodomain and extra-terminal domain (BET) family of epigenetic reader proteins, in control of ESC identity. We performed RNA-seq analyiss in the presense of small molecule inhibitors of BET proteins to show that BRD4 positively regulates the ESC transcriptome. We also integrated RNA-seq analysis with ChIP-sequencing datasets s for BRD4 (and for other BRD2 and BRD3) to demonstrate that BRD4 binds SEs and regulates the expression of SE-associated pluripotency genes. We have also conducted ChIP-seq analysis for Pol II binding to demonstrate that SE-associated genes depend on BRD4-dependent Pol II binding at TSS and gene body for their productive transcriptional elongation. Overall design: Total RNA was extracted from samples using the RNeasy Qiagen kit according to the manufacturer’s instructions. Deep sequencing of RNA (1ug) from hESCs FGF- or MS436-treated at day 1 and day 5 was performed as described in (Higgin et al., 2010c). Samples were subjected to PolyA selection using magnetic oligo-dT beads. The resulting RNA samples were then used as input for library construction as described by the manufacturer (Illumina, CA, USA). RNA libraries were then sequenced on the GAIIx system using 50bp single reads. Chromatin for ChIP-sequencing was obtained from FGF-maintained hESCs, vehicle or MS417-treated (at 250nM concentration for 6h) (10 to 20x106 cells/IP). ChIP-Seq libraries were generated using standard Illumina kit and protocol as described in (Ntziachristos et al., 2012). We performed cluster amplification and single read 50 sequencing-method using the Illumina HiSeq 2000, following manufacturer’s protocols.
Control of embryonic stem cell identity by BRD4-dependent transcriptional elongation of super-enhancer-associated pluripotency genes.
No sample metadata fields
View SamplesTranslocations involving the MLL genes are frequently found in Acute Myeloid Leukemia (AML) and are associated with poor prognosis. The MLL fusion proteins act as aberrant transcription factor activating a transcriptional program that transforms the cells, potentially through collaboration with other transcription factors. To investigate this we searched gene expression profiles from patients with MLL-rearranged AML compared with normal hematopoietic progenitor cells for transcriptional regulators and found targets of C/EBP to be up-regulated in the AML samples, suggesting that C/EBP might collaborate with MLL fusion proteins in the initial transformation process. We could show that transformation by MLL fusion proteins is dependent on C/EBP activity both in early progenitors as well as in GMPs. In contrast, C/EBP was found to be indispensable in an already established leukemia. These results suggest that C/EBP play an important role in the early transforming event of leukemogenesis.
Initiation of MLL-rearranged AML is dependent on C/EBPα.
Specimen part
View SamplesFibroblast growth factor-23 (FGF23), a circulating protein produced in bone, causes renal inorganic phosphate (Pi) wasting by down-regulation of sodium phosphate co-transporter 2a (Npt2a). The mechanism behind this action is unknown. We have previously generated transgenic mice (TG) expressing human wild-type FGF23 under the control of the 1 (I) collagen promoter. In this study we performed a large scale gene expression study of kidneys from TG mice and wild-type littermates. Several genes that play a role in Pi regulation had decreased expression levels, such as Npt2a, but also Pdzk1 which is a scaffolding protein known to interact with NPT2a. Importantly, the Klotho gene, a suggested crucial co-factor for FGF23 receptor binding and activation, was the most affected decreased gene. However, other genes proposed to regulate Pi levels, such as secreted Frizzled Related Protein 4 (sFRP4), Na+/H+ exchanger regulatory factor 1 (NHERF1) and the FGF-receptors 1-4, revealed no changes. Interestingly, expression levels of inflammatory response genes were increased and histological analysis revealed tubular nephropathy in the TG mice kidneys. In conclusion, FGF23 TG mice have altered kidney gene expression levels of several genes thought to be part of Pi homeostasis and an increase in inflammatory response genes, data supported by histological analysis. These findings may lead to further understanding of how FGF23 mediates its actions on renal Pi regulation.
Gene expression analysis of kidneys from transgenic mice expressing fibroblast growth factor-23.
Age
View SamplesRNase Y of Bacillus subtilis is a key member of the degradosome and important for bulk mRNA turnover. In contrast to B. subtilis, the RNase Y homologue (rny/cvfA) of Staphylococcus aureus is not essential for growth. Here we found that RNase Y plays a major role in virulence gene regulation. Accordingly, rny deletion mutants demonstrated impaired virulence in a murine bacteraemia model. RNase Y is important for the processing and stabilisation of the immature transcript of the global virulence regulator system SaePQRS. Moreover, RNase Y is involved in the activation of virulence gene expression at the promoter level. This control is independent of both the virulence regulator agr and the saePQRS processing and may be mediated by small RNAs some of which were shown to be degraded by RNase Y. Besides this regulatory effect, mRNA levels of several operons were significantly increased in the rny mutant and the half-life of one of these operons was shown to be extremely extended. However, the half-life of many mRNA species was not significantly altered. Thus, RNase Y in S. aureus influences mRNA expression in a tightly controlled regulatory manner and is essential for coordinated activation of virulence genes.
RNase Y of Staphylococcus aureus and its role in the activation of virulence genes.
No sample metadata fields
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Global target mRNA specification and regulation by the RNA-binding protein ZFP36.
Cell line, Treatment
View SamplesTristetraprolin/ZFP36/TTP and ELAVL1/HuR are two disease-relevant RNA-binding proteins (RBPs) that both interact with AU-rich sequences but have antagonistic roles. While ELAVL1 binding has been profiled in several studies, the precise in vivo binding specificity of ZFP36 has not been investigated on a global scale. We determined ZFP36 binding preferences using cross-linking and immunoprecipitation in human embyonic kidney cells and examined combinatorial regulation of AU-rich elements by ZFP36 and ELAVL1. Among the targets ZFP36 binds and negatively regulates the mRNA of genes encoding proteins necessary for immune function and cancer, and other RBPs. Using partial correlation analysis, we were able to quantify the association between ZFP36 binding sites and differential target RNA abundance from ZFP36 overexpression independent of effects from confounding features, such as 3 UTR length. We identified thousands of overlapping ZFP36 and ELAVL1 binding sites, in 1,313 genes. ZFP36 preferentially interacts with and regulates AU-rich sequences while ELAVL1 prefers predominantly U- and CU-rich sequences. RNA target specificity identified by global in vivo ZFP36-mRNA interactions were quantitatively similar to previously reported in vitro binding affinities. ZFP36 and ELAVL1 both bind an overlapping spectrum of RNA sequences, yet with differential relative preferences that dictate combinatorial regulatory potential. Our findings and methodology delineate an approach to untangle the in vivo combinatorial regulation by RNA-binding proteins.
Global target mRNA specification and regulation by the RNA-binding protein ZFP36.
Cell line, Treatment
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