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Showing: 41 - 60 of 342 results
  1. Plasmids 101: Inducible Promoters

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    Blog Post
    ...promoter is inactive because the activator protein cannot bind. After an inducer binds to the activator protein...direct activation. In this system, the activator rtTA (reverse tetracycline-controlled transactivator) is... are always active and thus referred to as constitutive promoters. Others are only active under specific...OFF state, the promoter is inactive because a bound repressor protein actively prevents transcription. Once...protein, the activator protein can bind to the promoter, turning it ON and initiating transcription.     ...derivatives serve as inducing agents to allow promoter activation. One of the most commonly used prokaryotic promoters...repressor (lacI protein) for transcription to be activated. In the presence of lactose or lactose analog ...
  2. Optogenetics + CRISPR, Using Light to Control Genome Editing

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    Blog Post
    ... optically active saCas9 protein. Stop light! Photoactive anti-CRISPRs halt Cas9 activity Anti-CRISPR...proteins heterodimerize and move the activator into position to activate gene transcription. The researchers...light-dependent activity to transcription, they fused BldD to the transcriptional activators p65 and VP64...can interfere with activity. The resulting system was coined as CRISPR–Cas9 activity switching via a novel...generate a photoactivatable nickase and a photoactivatable repressor (dCas9). The activity of all variants...Shining light on transcriptional activation using dCas9 Initial photoactivatable CRISPR systems published in...genomic anchor - an inactive, dead Cas9 protein (dCas9) fused to CIB1; and 2) the activator - the CRY2 photolyase...
  3. CRISPR History and Development for Genome Engineering

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    ... at specific loci. Activate or Repress : dCas9 fused to transcriptional activators or repressors can modulate...processed into individual crRNAs by a special trans-activating crRNA (tracrRNA) with homology to the short palindromic...for gene knockout, as well as transcriptional activation or repression. Combined with the power of next-generation...gRNAs: Truncated gRNAs display less off-target activity. High fidelity Cas9s: Three high fidelity Cas9...eSpCas9, and HypaCas9 display very low off-target activity due to rationally designed mutations. Researchers...CRISPR-Mediated Control of Gene Repression and Activation. Cell . 159(3):647-6. PMID: 25307932 Gilbert ...targeting multiple loci can be easily expressed in the same cell or organism. The ability to precisely target...
  4. 28 Hot Plasmid Technologies from 2015

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    Blog Post
    ...approach can also be used for activation of specific genes using dCas9-VP64 activator fragments (dCas9(C)-FKBP...endogenous gene activation. This system works by bringing together an anchor protein and activator protein to...portion of CRY2) fused to the p65 activation domain, which activates transcription of downstream genes...the targeted activation of endogenous genes and detail the time course of gene activation using this system...2015 Feb 23. A novel dCas9 activator capable of unprecedented activation of target genes A group of researchers...fused to a VP64 activator domain and targeted toward endogenous promoters to activate transcription. Chavez...synergistic effect on target gene activation. The novel dCas9-VPR activator is capable of enhancing target...
  5. Immunology Research Plasmids and Resources

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    Collection
    ...PLAU plasminogen activator, urokinase ATF, UPA, URK, u-PA PLAUR plasminogen activator, urokinase receptor...mitogen-activated protein kinase kinase 1 MAPKK1, MEK1, MKK1, PRKMK1 MAP2K2 mitogen-activated protein ...mitogen-activated protein kinase kinase kinase 14 FTDCR1B, HS, HSNIK, NIK MAP3K8 mitogen-activated protein...Cdc42/Rac)-activated kinase 1 MGC130000, MGC130001, PAKalpha PAK2 p21 protein (Cdc42/Rac)-activated kinase... protein (Cdc42/Rac)-activated kinase 4 - PAK6 p21 protein (Cdc42/Rac)-activated kinase 6 PAK5 PAK7 p21...the immune system triggers several processes to activate cells to recognize and get rid of infectious pathogens...
  6. How to Design Your gRNA for CRISPR Genome Editing

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    Blog Post
    ...balance maximizing on-target activity while minimizing off-target activity, which sounds obvious but can...to use a less-active gRNA that targets a truly unique site in the genome, or a more-active gRNA with one...that your gRNA sequence is designed to be highly active and reduce off targets. For CRISPRa and CRISPRi...to generate the desired edit. The wrench: Gene activation and inhibition by CRISPRa and CRISPRi Finally...expression at the level of transcription – CRISPRa (activation) and CRISPRi (inhibition) technologies – a nuclease-dead...100nt window downstream of the TSS gives the most activity. Thus, a given gene will only have a dozen or ...features to nominate gRNAs that are likely to be active, not only for SpCas9 but also for some other Cas...
  7. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

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    Blog Post
    ...sequences, Cas12a activity gets activated. This unleashes indiscriminate ssDNA cleavage activity which cleaves...sequence to bind to the sample and upon binding, gets activated. This activation results in a trans cleavage...detection.  Highlights: Cas13a is not catalytically active in the presence of two or more mismatches in the...complementary region in the target sequence and this activity results in the trans cleavage of the ssDNA-FQ ... given fluorescently labelled substrate, gets activated and performs non-specific collateral cleavage....cleavage by the enzyme and instead relies on its activity on the target regions thus making it an affinity-based...the Sashital Lab, Iowa State University. She is actively interested in science communication and enabling...
  8. Controlling for Off-target Effects with a New Genome-wide CRISPR Screen Design

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    Blog Post
    ...and predicted on-target activity was balanced with predicted off-target activity when selecting guides....lower off-target activity, but it could also be caused by a reduction of on-target activity. However, there...-target activity, Morgens et al drew some generalizable conclusions about off-target activity, demonstrate...off-target cutting without a reduction of on-target activity, but it’s unclear if this holds true in genome-wide...characteristics that influence gRNA off-target activity: 1) mismatches closer to the PAM are less tolerated...guides with high GC content have greater off-target activity. Short gRNAs have lower off-target cutting and...specificity with only a small loss of on-target activity in high-throughput screens. The human and mouse...
  9. Choosing a CRISPR Nuclease: Site Accessibility, Specificity, and Sensitivity

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    Blog Post
    ...by calculating the on-target activity divided by the off-target activity. Figure 2: Specificity...measure of off-target activity (left) while sensitivity is the measure of on-target activity (right). Cas9...Cas9 exhibits high on-target activity, but also high off-target activity, which may be undesirable in ...Specificity is the assessment of the off-target activity of Cas9. This can occur when Cas9 cleaves a site...specificity. Sensitivity is a measure of the on-target activity of the Cas9 nuclease. This can be determined by...Both of the enzymes showed decreased off-target activity relative to Cas9. Since then, the Joung and Jennifer...nuclease showed decreased or similar off-target activity, relative to eSpCas9 and SpCas9-HF across a number...
  10. New Optogenetic Tools for Cytoskeleton and Membrane Control

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    Blog Post
    ...to control Rho GTPase activity. A) Schematic of Opto-RhoGEF design and activity. B) OptoTIAM (magenta)...methods, the activity-based selection in mammalian cells used here could be an attractive strategy for... light-sensitive ion channels used to control activities like neuronal signaling — think of a mouse with...there’s a lot more to optogenetics than neuronal activity. Researchers have designed a variety of photoswitchable...severing. A) Schematic of Opto-katanin constructs and activity. EB3N-VVDfast-iLID (anchor) and SspB-mCherry-p60...microtubule severing and has very low dark-state activity and toxicity. All of that means this light-powered...Rho guanine-nucleotide exchange factors (GEFs) activate their partner Rho GTPase, leading to behaviors...
  11. Truncated gRNAs for Regulating Gene Expression

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    Blog Post
    .... "Orthogonal gene knockout and activation with a catalytically active Cas9 nuclease." Nature biotechnology...26167643. 3. Kiani, Samira, et al. "Cas9 gRNA engineering for genome editing, activation and repression."...fused to effector domains such as transcriptional activators or repressors. These fusion proteins retain the...majority have been shown to exhibit more limited activity than SpCas9 (2). In many cases this is due both...alternative approach is to modulate Cas9’s nuclease activity by modifying the gRNA with which it is complexed...capability remains intact while its nucleolytic activity is eliminated (Fig. 1) (1, 3). The gRNA can be...adapter capable of recruiting a transcriptional activator, robust regulation of gene expression is observed...
  12. Deciphering the Mysteries of Behavior with Viral Vectors

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    Blog Post
    ...receptor protein that activates neurons upon light stimulation. When they activated the Drd1 neurons 24 ...the ratio of time spent actively swimming versus passive floating. In the same paper, the authors used...neurons involved or whether their involvement is activating, inhibiting, or modulating. Viral vectors, in...networks involved in directly controlling muscle activity and coordinating movement, several additional ...the injection of AAV8 particles expressing an activating chemogentic receptor (hM3Dq) into a subset of...mice. When those neurons are chemogenetically activated, norepinephrine release causes a freezing response...develops an enhanced propensity for movement and activity called locomotor sensitization. This enhanced ...
  13. Fluorescent CRISPR Reporters: SRIRACCHA and GEmCherry2

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    Blog Post
    ...intensive and quite time consuming.   As Cas9/gRNA activity is crucial for successful CRISPR editing experiments...scientific community for efficient real-time Cas9 activity assays. Recently scientists have created CRISPR...reporter for assaying CRISPR/Cas-stimulated HDR activity) The Madison lab created SRIRACCHA in 2017 to ... system (iSRIRACCHA) where Cas9 expression is activated using 4-OH-T and doxycycline. A gRNA that targets...expressing cells provides a real-time read out of Cas9 activity.  By using the RFP:GFP ratio, edited cells can...SRIRACCHA enables scientists to both quantify Cas9 activity and sgRNA efficiency as well as enrich for mutants... fluorescent protein for assessing CRISPR/Cas9 activity Guide RNA structure and the site in the genome...
  14. Fluorescent Proteins 101: Photoactivatable Fluorescent Proteins

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    Blog Post
    ...used to activate the PA-FP should also be considered. If the light intensity needed for activation is too...reversibly reactivated by exposure to UV light. The fact that blue light both activates and inactivates Dronpa...Irreversible Photoactivatable Fluorescent Proteins Protein Oligomeric State Activating Light Pre/ Post... Reversible Photoactivatable Fluorescent Proteins Protein Oligomeric State Activating Light Pre/ Post...optimize your activation protocol for your particular set up. Applications of photoactivatable fluorescent... Additional PA-FP molecules are then activated in the same manner, until enough molecules have been analyzed...a specific wavelength of light. PA-FPs can be activated from low fluorescent states to high fluorescence...
  15. xCas9: Engineering a CRISPR Variant with PAM Flexibility

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    Blog Post
    ...compared xCas9 activity with wt SpCas9 in mammalian cells, finding xCas9 3.7 displayed about the same editing...polymerase subunit ω. This construct is designed to activate transcription from the accessory plasmid (AP) ...no-G PAM library to enrich for Cas9 variants with activity on non-NGG PAMs, generating xCas9 3.0-3.13. To...PAM flexibility might also increase off-target activity. Surprisingly, off-target effects across 5 gRNAs...editing Hu et al. also engineered transcriptional activators using the xCas9 scaffold. With an NGG PAM, xCas9...constructs modestly outperformed SpCas9-VPR in activating transcription. Sites containing NG, GAA, or GAT... GAT PAMs averaged 56-91% transcriptional activation compared to the NGG PAM, confirming the flexibility...
  16. CRISPR 101: Epigenetics and Editing the Epigenome

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    Blog Post
    ...et al., 2013). By comparing gene activation when enhancers were active or silent, they could identify the...Fusing dCas9 to a transcriptional activator like VP64 or VPR activates transcription, whereas dCas9-KRAB...work better than activators/repressors - dCas9-p300 increased transcriptional activation more than dCas9...decrease methylation and activate transcription. A lentiviral vector with the same modifier, Fuw-dCas9-Tet1CD...CRISPR activators and repressors are thought to be reversible once the effector is inactivated/removed... CRISPR Epigenetics resource. Transcriptional activation p300 acetyltransferase dCas9 fused to the catalytic...These marks are associated with transcriptional activation. Created with BioRender.com. Tet1 demethylase...
  17. Finding nucleic acids with SHERLOCK and DETECTR

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    Blog Post
    ...level. The Zhang lab has adapted natural RNase activity of the Cas13 protein to develop and optimize the... Cas13 and Cas12a, respectively, to cleave and activate a reporter. The detectable signal from this reporter...Cleavage of the quenchable fluorescent RNA by the “activated” Cas13 produces a quantifiable signal that indicates...Niewoehner and Jinek, 2016) and is conveniently activated by Cas13 ssRNA cleavage byproducts. Thus, binding...cleavage of a Cas13 specific reporter and the activation of Csm6. The Zhang lab showed that, by adding...base pairs with the dsDNA of interest, the DNase activity of Cas12a is initiated. Surrounding trans-ssDNA...unleashes indiscriminate single-stranded DNase activity. Science 360:436–439 . https://doi.org/10.1126...
  18. Fluorescent Proteins 101: Fluorescent Biosensors

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    ...substrate OR production of a product OR enzyme activity. Small molecule biosensors Addgene has many sensors...changing the FP’s structural organization and activating the fluorescent signal. Blue flame GECO biosensors...constructs are often used to monitor enzymatic activity or phosphorylation over time. You can also use...protein or DNA binding, enzyme or transcriptional activation, conformational changes, translation, and protein...plate well). Use to track a process (e.g. enzyme activity) over time or under various conditions Localization...fluorescently-labeled components Fluorescence-activated cell sorting (for cells); fluorescent HPLC (proteins...across membranes. These sensors generally follow the same pattern described above - a sensing domain induces...
  19. New and Upcoming Viral Vectors - Spring 2019

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    Blog Post
    ... a voltage sensor AAV Historically, electrical activity in the brain was measured with implanted electrodes...reporter allows a way to monitor neuronal electrical activity through imaging. Since it’s illuminated by red... also be used in conjunction with optogenetic activators and inhibitors that respond to blue light. We...fluorescence and resting fluorescence. It is useful for activity imaging of large populations of densely labeled...fluorescence and resting fluorescence.  It is useful for activity imaging of large populations of densely-labeled...flex PSAM4 GlyR IRES EGFP Chimeric channels for neuronal manipulation 119742  AAV5  AAV SYN PSAM4 GlyR...labeled neurons because background fluorescence from inactive neurons is reduced. 105322  AAV1  pGP-AAV-...
  20. FLEx Technology and Optogenetics: Flipping the switch on gene expression with high spatial and temporal resolution

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    Blog Post
    ...neural activity (Bernstein and Boyden, 2011; Mei and Zhang, 2012). For example, blue light activates channelrhodopsins...excitation, whereas yellow light activates halorhodopsins to silence neuronal activity (Figure 1) (Wiegert et al...targeted cells makes it possible to control neuronal activity with a specificity far greater than the one that...specific wavelengths, selectively turning neuron activity on or off (Atasoy et al., 2008; Taylor et al.,...unclear which subpopulation of DA neurons could activate appetitive rather than aversive stimuli. In a ... this question, mapping and characterizing the activity of the DA neurons of the VTA. Using in vivo optogenetic...genetically targeted optical control of neural activity." Nature neuroscience 8.9 (2005): 1263. PubMed...
Showing: 41 - 60 of 342 results