CRISPR-Cas9 transcriptional repressors have emerged as robust tools for disrupting gene regulation in vitro but have not yet been adapted for delivery in adult animal models. Here we created an S. aureus Cas9-based transcriptional repressor (dSaCas9KRAB) compatible with adeno-associated viral (AAV) delivery. To evaluate dSaCas9KRAB efficacy for targeting an endogenous gene in vivo, we silenced transcription of Pcsk9, a regulator of cholesterol levels, in the liver of adult mice. Systemic administration of a dual-vector AAV8 system expressing dSaCas9KRAB and a Pcsk9-targeting guide RNA (gRNA) resulted in significant reductions of serum PCSK9 and cholesterol levels. Despite a moderate host response to dSaCas9KRAB expression, PCSK9 repression was maintained for 24 weeks after a single treatment, demonstrating the potential for long-term gene silencing in post-mitotic tissues with dSaCas9KRAB. In vivo programmable gene silencing enables studies that link gene regulation to complex phenotypes and expands the CRISPR-Cas9 genetic perturbation toolbox for basic research and gene therapy applications. Overall design: C57Bl/6 wild-type mice were treated with AAVs expressing dSaCas9-KRAB and/or a Pcsk9-targeting gRNA by tail-vein injection. Six weeks after treatment, we harvested the livers of treated mice and performed mRNA-sequencing.
RNA-guided transcriptional silencing in vivo with S. aureus CRISPR-Cas9 repressors.
Specimen part, Cell line, Subject
View SamplesEpigenetic modifications determine the structure and regulation of eukaryotic genomes and define key signatures of cell lineage specification. Technologies that facilitate the targeted manipulation of epigenetic marks could be used to precisely control cell phenotype or interrogate the relationship between the epigenome and transcriptional control. Here we have generated a programmable acetyltransferase based on the CRISPR/Cas9 gene regulation system, consisting of the nuclease-null dCas9 protein fused to the catalytic core of the human acetyltransferase p300. This fusion protein catalyzes acetylation of histone H3 lysine 27 (H3K27) at its target sites, leading to robust transcriptional activation of target genes from promoters, proximal enhancers, and distal enhancers. In contrast to conventional dCas9-based activators, the acetyltransferase fusion effectively activated genes from enhancer regions and with individual guide RNAs. The core p300 domain was also portable to other programmable DNA-binding proteins. This technology enables the targeted perturbation of native epigenetic architecture and will be useful for reprogramming the epigenome for applications in genomics, genetics, disease modeling, and manipulating cell fate. Overall design: HEK293T cells were transfected in triplicate with plasmids expressing synthetic transcription factors. The synthetic TFs were either (a) dCas9-VP64 fusion protein and a targeting guide RNA (gRNA), or (b)dCas9-p300 fusion protein containing the catalytic domain of p300 and a targeting guide RNA (gRNA). As a control, cells were transfected with plasmids expressing dCas9 alone and dCas9 fused with a aceryltransferase null mutatnt form of the p300 catalytic domain (D1399Y, as in text). After transfection, RNA-seq was used to identify differential expressin at on-target and off-target sites.
Epigenome editing by a CRISPR-Cas9-based acetyltransferase activates genes from promoters and enhancers.
No sample metadata fields
View SamplesSynthetic transcription factors can be applied to many areas of biotechnology, medicine, and basic research. Currently, the most common method for engineering synthetic transcription factors has been based on programmable DNA-binding domains of zinc finger proteins, Transcription Activator-Like Effectors (TALEs), and most recently the CRISPR/Cas9 system. These transcription factor platforms consist of the DNA-binding domain fused to potent transcriptional activation domains, most commonly the tetramer of the minimal transactivation domain of the VP16 protein from herpes simplex virus, referred to as VP64. Although many applications are well-suited for the targeted activation of a single gene, genetic reprogramming requires the coordinated regulation of many nodes of natural gene networks as is typically performed by naturally occurring reprogramming factors. Thus we sought to combine principles from each of these approaches by attaching potent transcriptional activation domains to a natural reprogramming factor to increase the efficiency and/or rate of cell fate conversion. In this study, we evaluated the effects of fusing potent activation domains to the transcription factor MyoD, the master regulator of the skeletal myoblast lineage. In certain non-myogenic lineages, MyoD overexpression causes upregulation of the myogenic gene network and conversion to a myoblast phenotype including cell fusion into multinucleated myotubes. Compared to wild-type MyoD, the VP64-MyoD fusion protein induced greater overall reprogramming of global gene expression. This simple approach for increasing the potency of natural reprogramming factors circumvents the need for screening engineered proteins and leads to a more robust cellular reprogramming compared to treatment with the wild type transcription factor. Overall design: Human dermal fibroblasts were transduced with a single tet inducible lentivirus that expresses either WT-MyoD or VP64-MyoD in response to treatment with doxycycline. Untreated human dermal fibroblast served as the negative control. Gene expression was measured using mRNA-seq, and differential expression was calculated using DESeq. All experiments were performed in biological duplicates.
Enhanced MyoD-induced transdifferentiation to a myogenic lineage by fusion to a potent transactivation domain.
No sample metadata fields
View SamplesSynthetic transcription factors can be applied in many areas of biotechnology, medicine, and basic research. In contrast to current methods based on engineering new DNA-binding proteins, we show that Cas9 fused to a transcriptional activation domain can be targeted by combinations of guide RNA molecules to induce the expression of endogenous human genes. This simple approach for targeted gene activation circumvents the need for engineering new proteins and will enable widespread synthetic gene regulation. Overall design: HEK293T cells were transfected with plasmid expressing Cas9-VP64 fusion protein and a guide RNA. As a control, empty guide RNA was transfected. Gene expression was then measured using mRNA-seq, and differential expression calculated using DESeq. All experiments were performed in biological duplicates or triplicates.
RNA-guided gene activation by CRISPR-Cas9-based transcription factors.
Cell line, Subject
View SamplesPurpose: The goals of this study are to identify the transcriptional profile of retinal ganglion cells (RGCs) with the capacity to regenerate an axon, and contrast this profile with the profile of RGCs that cannot regenerate an axon. Methods: See sample pages for protocols for tissue preparation, RNA extraction and purification, library construction and data processing. Results: RNA from the 12 samples was sequenced to an average depth of 42 million reads. Genes were considered expressed if a gene had an expression of 1 count per million in 3 of the 12 samples. There were 13,406 genes that met this criterion. Conclusions: Our study represents the first analysis by NGS of highly-purified RGCs in the context of axonal injury Overall design: RGC mRNA profiles of melanopsin RGCs and ON-OFF Direction Selective Ganglion Cells (ooDSGCs) were generated by deep sequencing in triplicate, using Illumina HiSeq 2500.
Thrombospondin-1 Mediates Axon Regeneration in Retinal Ganglion Cells.
Specimen part, Subject
View SamplesCerebral organoids, three-dimensional cultures that model organogenesis, provide a new platform to investigate human brain development. High cost, variability and tissue heterogeneity limit accessibility and broad applications of current organoid technologies. Here we developed a miniaturized spinning bioreactor (SpinO) to generate forebrain-specific organoids from human iPSCs. These organoids recapitulate key features of human cortical development, including progenitor zone organization, neurogenesis, gene expression, and importantly, a distinct human-specific outer radial glia cell layer. We have also developed protocols to generate midbrain and hypothalamic organoids. Finally, we employed this forebrain organoid platform to model Zika virus (ZIKV) exposure. Quantitative analyses revealed that preferential, productive ZIKA infection of cortical neural progenitors leads to increased cell death and reduced proliferation, resulting in decreased neuronal cell layer volume that resembles microcephaly. Together, our brain region-specific organoids and SpinO provide an accessible and versatile platform for modeling human brain development and diseases, and for compound testing. Overall design: Time course of human cerebral organoid cultures. No Zika virus infection is involved.
Brain-Region-Specific Organoids Using Mini-bioreactors for Modeling ZIKV Exposure.
Subject, Time
View SamplesZebrafish (Danio rerio) gutGFP transgenic embryos [Tg(XlEef1a1:GFP)s854] were collected at 4 time points: 2 days post fertilization (dpf), 3, dpf, 4 dpf, 6 dpf. Embryos were dissociated into single cells and sorted by FACS based on GFP expression.
FACS-assisted microarray profiling implicates novel genes and pathways in zebrafish gastrointestinal tract development.
Age
View SamplesWe used microarray to characterize interferon stimulated genes in dendritic cells
Comparative analysis of anti-viral transcriptomics reveals novel effects of influenza immune antagonism.
Specimen part
View SamplesThe objective of this study was to determine the effects of LANA on the expressions of the cellular genes. Overall design: BJAB cells were transduced with lentiviral vector expressing LANA or the control vector, total RNA was extracted for the detection of relative expression of cellular genes in LANA expressing cells.
KSHV LANA upregulates the expression of epidermal growth factor like domain 7 to promote angiogenesis.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Diversity in Compartmental Dynamics of Gene Regulatory Networks: The Immune Response in Primary Influenza A Infection in Mice.
Sex, Specimen part, Treatment, Subject, Time
View Samples