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We narrowed to 814 results for: Ran;

Showing: 241 - 280 of 814 results
  1. pCXLE toolkit: Efficient episomal plasmid-based method to reprogram peripheral blood cells to iPSCs

    Type
    Blog Post
    Published
    Dec. 14, 2017, 2:08 p.m.
    ...hiPSCs for clinical purposes: mRNA transfection- this allows transient expression of the reprogramming factors...cells, thus expressing additional EBNA-1 transiently. The transiently expressed EBNA-1 increases protein expression...insertional mutagenesis, which is the integration of transgenes into the genome that can cause disruption of ...express reprogramming factors To date, the mRNA transfection method has not been used successfully to derive...using PBMCs as the source of somatic cells. This translates to only about 16 hiPSC colonies per 100 ml of...such low efficiency of reprogramming is a major hindrance in using PBMCs as a source of somatic cells for...system thus provides a practical way to generate transgene-free, virus-free clinical grade hiPSCs from easily...
  2. Plasmids 101: Gram Negative and Positive Bacteria

    Type
    Blog Post
    Published
    Aug. 2, 2022, 1:15 p.m.
    ...diderms, have a thinner peptidoglycan membrane and an outer lipid membrane. Common gram negative bacteria include...within their membrane, while the stain is washed from the gram negative bacteria’s thinner membrane. Procedure...destroys the outer lipid membrane, and the thin inner peptidoglycan membrane is unable to retain the stain...expanded on Gram’s discovery, adding a second stain, safranin, as a counterstain to help visualize the bleached...or monoderms, have a single thick peptidoglycan membrane. Common gram positive bacteria include staphylococci...and immediately rinse. Flood the smear with the safranin counterstain for 30 - 60 seconds. Rinse the slide...interaction of CV+ and I- in the thick multilayered membrane of the gram positive bacteria. In a gram negative...
  3. Optimizing Donor DNA for Enhanced CRISPR Genome Editing

    Type
    Blog Post
    Published
    March 24, 2016, 2:30 p.m.
    ... of the four strands of the cleaved duplex, while the fourth strand (the released strand in Figure 1 below...discovered that single stranded donor DNA: Complementary to the released strand, 127bp in length, With...single or double stranded donor DNA with other design parameters. Example single stranded donor DNA and ...presented in Figure 2. Figure 2: Single-stranded donor DNA interaction with the Cas9-DNA duplex...accessible to anneal with complementary single stranded DNA. We thus wondered if such a structure could... that are an order of magnitude greater than transfection approaches. Moreover, the cost of reagents is...relatively modest, requiring expressed Cas9 protein, transcribed sgRNA, and optional donor DNA. Chris Richardson...
  4. Viral Vectors 101: Types of viruses

    Type
    Blog Post
    Published
    June 6, 2023, 1:15 p.m.
    ... Retroviruses are single-stranded RNA viruses that use reverse transcriptase to synthesize complementary...for most experimental needs, and can transduce (infect) a wide range of cell types with a high efficiency... such as a heterologous envelope or a post-transcriptional regulatory element can be used for either type...Adeno-associated virus (AAV) is a small, single-stranded DNA parvovirus. AAV can infect humans and some...response as retroviruses. This virus can also transduce dividing and non-dividing cells, making it conducive...issue. Adenovirus Adenovirus has a linear, double stranded DNA genome which is non-enveloped. It can infect...Adenovirus is an effective option if you need high, transient expression of a genetic cargo or have a very large...
  5. Top Requested Lentivirus and AAV of 2016

    Type
    Blog Post
    Published
    Jan. 6, 2017, 3:56 p.m.
    ...AAV5, AAV8) enable different patterns of transduction and transgene expression across different cell types..., Rumpel S. Analysis of transduction efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5...expressed from your cell line of choice after transduction with this virus. While various Cas9 mutants ...classic Cas9 nuclease, which introduces double stranded DNA breaks, can be expressed from lentiCas9-Blast...single stable Cas9-expressing cell line and then transduce this line with lentiviruses expressing various...experiments and over time (as compared to separate transductions with a single-vector system). Tips for using...is used to attain cell-specific expression in transgenic animals, where cre expression is restricted to...
  6. Supporting Rare Disease Research with the 2020 BeHEARD Awards

    Type
    Blog Post
    Published
    Sept. 8, 2020, 2 p.m.
    ...SLC6A8 mutations in Creatine Transporter Deficiency Creatine Transporter Deficiency (CTD) is a rare X-... to be transported from the blood and cross the blood brain barrier using creatine transporters. However...However, mutations in the transporter SLC6A8 impede this transport and result in global creatine deficiency...Accelerate Research Discoveries) Challenge provides grants for rare disease research. This year is our fourth... the SLC6A8 gene, also known as the creatine transporter. The Association for Creatine Deficiencies (ACD...GPCRs) detect molecules outside of the cell and translate those signals into cellular responses. For example...consist of many parts that work together on the cell membrane. Germline mutations in one of these parts, the...
  7. Channelrhodopsins with improved light sensitivity for minimally-invasive optogenetics

    Type
    Blog Post
    Published
    Nov. 3, 2020, 2:15 p.m.
    ... that determine membrane expression and plasma membrane localization of transmembrane proteins, like rhodopsins...capable of broad transduction of the nervous system which eliminates the need for intracranial injections. ... to perform in vivo optogenetic experiments. Intracranial injections of AAV are commonly used to deliver...channelrhodopsin-based optogenetics minimally-invasive, Frances Arnold’s lab and Viviana Gradinaru’s lab used machine...neurons and mouse brain slices collected following intracranial injection of an AAV expressing a ChRger. In ...performed well in a tissue culture dish, that doesn’t guarantee their success in vivo. Therefore, the Arnold and...their cage. Since dopamine is an important neurotransmitter that promotes reward-motivated behavior, if...
  8. Plasmids for Endogenous Gene Tagging in Human Cells

    Type
    Blog Post
    Published
    April 6, 2017, 1:02 p.m.
    ... copy. The coding sequence for GFP is transcribed and translated along with the gene, producing both a...exon of the gene to ensure it would be transcribed and translated. For an N-terminally tagged protein, ...destroyed by CRISPR/Cas9 during transfection. Making the double strand break and introducing the tag through...base pairs on each side, in fact. Later, when we transfect the cells, these large regions of homology enable...directed repair (HDR) process following the double strand break CRISPR/Cas9 makes at the target site. The...technique that briefly destabilizes the cell’s outer membrane and allows the components to physically enter ...go to work. Figure 3: Inducing the double strand break and introducing the tag. Created with BioRender.com...
  9. Lab Automation at Addgene

    Type
    Blog Post
    Published
    March 22, 2018, 1:28 p.m.
    ...bacterial transformation One protocol that has been automated is high throughput transformation. With our... to do up to 96 transformations in one run compared to doing about 50 transformations in the same amount...easier and more efficient. Here, I’ll discuss transformation, DNA purification, and filling vials with agar...deposits (over 100 deposits per month!), manual transformations were taking a lot of time. Enter the Biomek... We wanted a machine that would improve our transformation protocol and, after looking at a few options... - one pod can pick up 96 tips for easy sample transfer between 96 well plates. The second pod can pick...out your samples. This can be useful if you’re transferring samples from 96 wells plates onto agar q-trays...
  10. Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering

    Type
    Blog Post
    Published
    Dec. 15, 2016, 3:57 p.m.
    ...selectable, it can be transferred to a different genetic background via P1 transduction. Plasmid Expressing...products: 1) a partially dsDNA duplex with single-stranded 3’ overhangs or 2) if the dsDNA was short enough...enough, a ssDNA whose entire complementary strand was degraded. Beta: Beta protects the ssDNA created by...higher recombination frequency when the lagging strand of DNA is targeted, it’s best to determine the ...design an oligo that is complementary to the lagging strand. In practice, it’s easier to not determine the ...replication and instead design oligos that target both strands. One of the two oligos will recombine with a higher...you’ll find out empirically which is the lagging strand. ssDNA substrate is more efficient than dsDNA with...
  11. Antibodies 101: Validation

    Type
    Blog Post
    Published
    March 24, 2022, 1:15 p.m.
    ...Interest (GOI), and transfect it into your favorite cell line. In parallel, you transfect cells with another...antigen - Recognition of an immunogen does not guarantee recognition of the target antigen. You want to...Antibody-independent methods may include analysis of transcriptomic or proteomic data from several different tissues...non-specific, background signal, so you’ll need a range of expression strengths to be confident in your ... feasible and (2) large-scale proteomic and transcriptomic datasets already exist.   Example: You want...tissues. You know that there is a wealth of transcriptomic data from this sample type, so you use your...need to be aware of any possible alternative translation start sites or alternative splicing that could...
  12. An Introduction to Adenovirus

    Type
    Blog Post
    Published
    Oct. 3, 2023, 1:15 p.m.
    ...host range and tissue tropism (Borkenhagen et al., 2019). AdVs are non-enveloped double-stranded DNA viruses... protein translation. Its genome consists of “early” (E) and “late” genes, and the transition between ...sequence (transgene) instead.    Although the late genes are usually present in the transfer plasmid for... (and therefore between early and late gene transcription) is demarcated by viral genome replication (...vectorization strategies include creating an AdV transfer plasmid with the E1 and E3 (Early 1 and Early ...cells that are infected by the vector, only the transgene will be expressed, since the early genes are absent...possible to design a vector that achieves persistent transgene expression in certain cell types (Tatsis et al...
  13. CRISPR 101: Making a Knock-In Cell Line

    Type
    Blog Post
    Published
    Dec. 22, 2022, 2:15 p.m.
    ...(single vs. double stranded) all depends on the size of the knock-in. Single strand oligonucleotide donors...knock-out. The goal of a knock-out is to disrupt DNA translation by generating a frameshift mutation. The majority...pathway cells already have for repairing DNA double strand breaks – (HR). HR is the dominant homology-directed... Fig. 1: Early steps in repair of a DNA double strand break by homologous recombination.    Designing...have larger homology arms in the 500 bp to 1 kb range, however, shorter homology tracts have recently ...recognition sequence in the donor DNA, you can guarantee there won’t be re-targeting after HDR. If your...cycle regulatory proteins responsible for the transition out of S phase, so cells stay in an HDR-promoted...
  14. Don’t FRET: Bimolecular Fluorescence Complementation Makes Visualizing Protein-Protein Interactions Easy

    Type
    Blog Post
    Published
    Aug. 27, 2020, 1:15 p.m.
    ...Forster Resonance Energy Transfer (FRET). Through the non-radiative transfer for energy between neighboring...Whether BiFC constructs are expressed transiently by transfection or stably impacts the success of BiFC..., kinase signaling, integrin signaling, and transcription factor interactions (Kerppola, 2006). One of...interactions between basic leucine zipper and Rel transcription factors (Hu et al., 2002). This would be more...overexpression of fusion proteins it requires can lead to aberrant subcellular localization of the studied PIPs. ...frame (ORF) library to screen PPIs among 450 transcription factors in live fruit flies. Although BiFC open-reading... high background fluorescence levels due to the random association between FP fragments independent of...
  15. CRISPR 101: Cas9 Nickase Design and Homology Directed Repair

    Type
    Blog Post
    Published
    March 15, 2018, 12:59 p.m.
    ...nickase. Nickases create a single-strand rather than a double-strand break, and when used with two adjacent...the target strand. Conversely, the H840A mutation in the HNH domain creates a non-target strand-cleaving...strand-cleaving nickase. Instead of cutting both strands bluntly with WT Cas9 and one gRNA, you can create a staggered...to each other? The gRNAs must target different strands to create a DSB, but this can be accomplished with... benefit of using nickases for HDR is targeting range: using an individual gRNA with WT Cas9, repair levels...experiment to insert an EcoRI site using a single-stranded oligonucleotide (ssODN) donor. Using a D10A nickase...across the 51 nt region using either a top or bottom strand ssODN donor with 40 bp homology arms. The HDR efficiency...
  16. Deep Dive: qPCR

    Type
    Blog Post
    Published
    Sept. 29, 2022, 1:15 p.m.
    ...increase as the DNA amplicon transitions from single-stranded to double-stranded, and finally, drop once more... by abundant transcripts, leading to falsely lowered levels for less abundant transcripts. However, adding...can even be used to detect a single copy of a transcript. But this sensitivity can sometimes cause as ...signals are produced by the presence of double-stranded DNA, when temperatures are high, signal intensity...reflecting the presence of primarily denatured (single-stranded) DNA. As the temperature drops, single intensity...assumption that there is a smooth, single-step transition between ssDNA and dsDNA. This is not true for...effects, cation concentrations and a temperature range) to predict PCR melting curves and dynamic melting...
  17. Rett Syndrome: A History of Research and Therapeutic Outlooks

    Type
    Blog Post
    Published
    Nov. 19, 2020, 2:15 p.m.
    ...References: Amir RE, Van den Veyver IB, Wan M, Tran CQ, Francke U, Zoghbi HY (1999) Rett syndrome is caused...collection of molecular biology tools so that both veteran and new Rett researchers can find the reagents ...maturation (Tillotson & Bird, 2019) and is a global transcriptional regulator of thousands of genes. Studies have...have suggested roles in transcriptional repression, activity dependent de-repression, chromatin remodeling...groove of AT-rich DNA sequences to regulate transcription (Baker et al., 2013). Mutations that affect ...gene editing, MECP2 reactivation, RNA editing, RNA trans-splicing, and protein replacement to reverse the...in animal models, Rett syndrome is a strong translational candidate for gene replacement therapy. In 2014...
  18. What the HEK?

    Type
    Blog Post
    Published
    April 18, 2023, 1:15 p.m.
    ...the Netherlands. Transformation of HEK cells with adenovirus 5 DNA was postdoc Frank Graham’s 293rd experiment...endothelial, epithelial, or fibroblast. However, Frank Graham showed HEKs display many immature neuron-...with kidney cells (Shaw et al.). Since then, transcriptome studies of the cell line have determined it ...replication. To generate a virus, you need only transfect the ‘helper’ plasmids (viral packaging machinery...cell or organism. This pipeline is utilized to transduce cell lines for basic science research all the ...Protein production  HEKs are extremely easy to transfect in bulk and produce recombinant proteins at high...cell line model for cancer-specific research. Membrane receptors and ion channels are often exogenously...
  19. New Neuroscience Tool: The iGluSnFR3 Glutamate Sensor

    Type
    Blog Post
    Published
    April 7, 2022, 1:15 p.m.
    ...three different membrane-targeting flavors – PDGFR, GPI, and SGZ, to improve neuronal membrane trafficking...properties such as kinetics, ∆F/F0, SNR, dynamic range, photostability, quantum yield, and expression. ...segment (PDGFR TMD) that anchors the sensor to the membrane and displays it on the extracellular side. In .... PDGFR is a C-terminal fusion to the PDGFR transmembrane domain in the mammalian expression pMinDisplay...glycosylphostidylinositol anchor. SGZ contains a PDGFR transmembrane domain, followed by a modified form of the cytosolic...fluorescent probe for visualizing glutamate neurotransmission.” Nature Methods (2013) PubMed PMID: 23314171...kinetics and localiation for imaging synaptic transmission” bioRxiv (2022)...
  20. Viral Vectors 101: Biosensors

    Type
    Blog Post
    Published
    July 6, 2023, 1 p.m.
    ... engineered to detect a wide array of neurotransmitters ranging from dopamine to glutamate, all the way... or animal system. This ‘thing’ could be a neurotransmitter, such as norepinephrine, or an electrolyte...last component of the biosensor is the signal transducer which will quantitatively give a readout for ...bio-recognition event is (fluorescence, pH, etc.). The transducer will generate a numerical value which represents...activated GFP expression (receptor), then the transducer could be a microscope, plate reader, or any other...—keep reading to find out how!   Neurotransmitters Many canonical fluorescent as well as FRET-based...fluorescence-based and have been optimized for a wide-range of uses to monitor the fundamental cellular building...
  21. Viral Vectors 101: Viruses as Biological Tools

    Type
    Blog Post
    Published
    March 21, 2023, 1:15 p.m.
    ...one they have a high transduction efficiency and can effectively infect a wide range of cell types that ...used to achieve transient, high expression of the relevant cargo without the fear of random genomic integration... Packaging Capacity (>8kb) High Transduction Efficiency Transient Gene Expression High Immunogenecity...viral envelope, which fuses with the target cell’s membrane, allowing the viral particle access into the cell...that are typically ‘difficult to transfect’, such as primary cells. They can also be directly injected into...Immunogenicity Infects Non-Dividing Cells Transient Gene Expression Low Tropism for Mouse Cells and...out How to Get the Most from Your Lentiviral Transduction Additional Resources on Addgene.org Browse...
  22. Hot Plasmids - May 2022

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    Blog Post
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    May 26, 2022, 1:15 p.m.
    ...use of pre-existing transgenic lines, termed BLITZ (Biotin Labeling In Transgenic Zebrafish) (Xiong, et...“single-use” transgenic lines. Instead, researchers can generate and maintain transgenic lines that can...protein by a specific transcription response element (TRE) or kinase translocation reporters (KTRs). Find...interest and, for in vivo work, generate a dedicated transgenic line. Using zebrafish as a model organism, the...protein can then be co-expressed in essentially any transgenic zebrafish line expressing a GFP-tagged version...generational evolution of the AAV capsids (left) and transduction patterns (right).  Both AAV-PHP.eB and the AAV.CAP-B...target. Across all loci tested, error rates overall ranged from 0.3% to 10%, in comparison to the 62-90% error...
  23. AAV Q&A with Tim Miles

    Type
    Blog Post
    Published
    May 17, 2022, 1:15 p.m.
    ...been able to successfully systemically transduce and then retransduce a model organism such as mice, e.g....potential strategy is to use split-inteins to mediate trans-protein splicing. Note, however, that this will ... at a high MOI, often resulting in a drop in transduction coverage compared to just one vector.   Q2: ... Q4: Are there any AAVs that have successful transduction in microglia? I have been using the AAV.PHP....information.   Q6 & Q7: We have been attempting to transduce mouse liver via tail vein injections but would...capsid was reported for specific and potent liver transduction. While we have not tried it, it might be worth...Animal Models Q9: Is there any difference in transfection efficiency when delivering these viruses via...
  24. Hot Plasmids - February 2022

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    Blog Post
    Published
    Feb. 22, 2022, 2:15 p.m.
    ...-HA frankenbodies include mEGFP, mCherry, and HaloTag. Figure 1: (a) Anti-FLAG frankenbody (FB)...Here's what you'll find in this post: Anti-FLAG Frankenbodies for modular imaging of cellular targets Optimized...mammalian genome regulation and editing Anti-FLAG Frankenbodies for modular imaging of cellular targets by: ...: Mike Lacy Adding to their set of anti-HA frankenbodies (Zhao et al. 2019), Tim Stasevich and Hiroshi... have recently published a set of anti-FLAG frankenbodies, a flexible, modular tool for labeling. Here...variety of applications. This set of new anti-FLAG frankebodies includes mEGFP, mRuby2, iRFP713, SNAP-tag, and...Liu et al. 2021. Anti-FLAG and anti-HA frankenbodies have a variety of applications, including live-cell...
  25. CRISPR 101: Cas9 vs. The Other Cas(s)

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    Blog Post
    Published
    Dec. 8, 2022, 2:15 p.m.
    ... it will proceed to generate a blunt DNA double strand break. Cas9 has been studied for genome engineering...an expanding number of others. Best for: a wide range of DNA edits.   Cas3 – The shredder What sets Cas3...locates its target sequence and initiates single stranded DNA degradation. Cas3 DNA digestion can proceed...convenient for targeting experiments requiring single strand DNA generation, such as homology directed-repair...therapeutic delivery.   Cas14 – Mini, but single strand mighty Unlike many other Cas enzymes, Cas14 targets...This makes it particularly useful in generating transient edits of signaling molecules (RNA) as opposed ...for targeting mRNA and useful as a mechanism of transient knockdown of gene expression. This system could...
  26. Teaching an Old DOG New Tricks: Controlling Protein Activity with GFP

    Type
    Blog Post
    Published
    Nov. 24, 2015, 3:30 p.m.
    ... to create a complete transcription factor, activating luciferase transcription. Tang et al. coined this...Connie Cepko’s lab allow researchers to activate transcription or Cre recombinase activity only in the presence...Using nanobodies to create GFP scaffolds for transcriptional activation The project began with a frustration... in their 293 cell culture system. In cells cotransfected with GFP and the GBPs, GFP linked the two GBPs...this system T-DDOG (Transcriptional Devices Dependent On GFP). In testing the specificity of their system... dsRed, mCherry, and TdTomato do not induce transcription. Thus, T-DDOGs can be used in combination with...T-DDOG results showed that GFP could regulate transcription in a cell-type specific manner, and Tang and...
  27. Plasmids 101: Modular Cloning

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    Blog Post
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    March 12, 2024, 1:15 p.m.
    ...into… Transcription units (TUs), which are functional units composed of multiple parts transcribed together...a protein that regulated its own transcription, or the transcription of another gene? Now you have a genetic...As a plasmid repository, we are no strangers to cloning. If you’re reading this, then chances are you...hierarchical levels: individual DNA parts, transcriptional units, and multigene constructs. Let’s start...start by examining individual parts and transcriptional units. Individual parts are defined DNA sequences...assembled into larger functional units which are transcribed together. Image courtesy of Robert Hurt. ... with DNA, and these complexes regulate the transcription of specific genes. What if one of those genes...
  28. Educational Planarian Tools for Teaching Developmental Biology Techniques

    Type
    Blog Post
    Published
    May 24, 2018, 1:20 p.m.
    ...remove one strand of the siRNA and are directed by complementarity to the remaining single stranded siRNA ...activity or their translation disrupted through physical blocking of the translation machinery. In the...WISH) for visualizing expression of genes. Double-stranded RNA (dsRNA)-mediated RNA interference (RNAi) to... by T7 promoters to allow for bidirectional transcription to create dsRNA. Students can produce DNA templates...the temporal and spatial localization of mRNA transcripts in tissue. This is useful for labeling specific...mixing with the liver paste, these E. coli are transformed with the appropriate plasmid and dsRNA expression...Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans. Nature, 391 (1998...
  29. PRIDICT: Predicting Efficiencies of Prime Editing Guide RNAs

    Type
    Blog Post
    Published
    June 25, 2024, 1:15 p.m.
    ..., and deletions) without introducing DNA double-strand breaks (Anzalone et al., 2019; Chen & Liu, 2023...typically a Cas9 H840A nickase fused to a reverse transcriptase) together with a prime editing guide RNA (pegRNA...containing a primer binding site and a reverse transcription template (RTT). The design of the pegRNA has...provides users with different designs of pegRNAs, ranked by their PRIDICT/PRIDICT2.0 score. For the best...editing strategies) based on a DeepSpCas9 score ranking (Kim et al., 2019). PRIDICT saves time and resources...doi.org/10.1016/J.CELL.2013.07.018 Anzalone, A. V., Randolph, P. B., Davis, J. R., Sousa, A. A., Koblan, L....Search-and-replace genome editing without double-strand breaks or donor DNA. Nature, 576(7785), 149–157...
  30. AAV Vector Quality Control: Going the Extra Mile with NGS

    Type
    Blog Post
    Published
    Sept. 12, 2017, 1:44 p.m.
    ...serotype. Additionally, we check viral transgene expression in transduced cells whenever possible. This post... for transgene expression. Once packaged in AAV, this pre-recombined DNA could lead to transgene expression... to these expected hits, we always get hits to “random” genes. Do these hits always mean the sample is...wanted to see how low we could go. We prepared a range of spiked samples from 0.1-20% and discovered that...find the optimal dose that allows for sufficient transgene expression but limits the likelihood of recombinase-independent...pioneering the systematic use of this new QC assay to guarantee that you receive the best AAV vectors for your...Broucque F, Robin C, Hebben M, Merten O-W, Blouin V, François A, Redon R, Moullier P, Léger A (2015) Advanced...
  31. Fluorescent Proteins 101: Visualizing Subcellular Structures & Organelles

    Type
    Blog Post
    Published
    June 22, 2017, 2:30 p.m.
    ...can be gained by understanding the location and transport of the protein within a living cell. Analyzing...Analyzing differences in protein localization and transport between healthy and diseased states can also provide...endoplasmid reticulum, modified in the golgi and then transported in vesicles via the secretory pathway to their...the end of their life cycle, proteins may be transported through the vesicles to the lysosome where they... of an organelle or involved in intracellular transport pathways, it is possible to map the internal organization...this case the cell needs to be fixed and the cell membrane permeabilized in order for the antibodies to reach...used markers for major mammalian organelles and transport pathways. It is best, though not always possible...
  32. xCas9: Engineering a CRISPR Variant with PAM Flexibility

    Type
    Blog Post
    Published
    March 28, 2018, 6:52 p.m.
    ...xCas9 for transcriptional regulation and base editing Hu et al. also engineered transcriptional activators...activating transcription. Sites containing NG, GAA, or GAT PAMs averaged 56-91% transcriptional activation... to create xCas9, an enzyme recognizing a broad range of PAMs like NG, GAA, and GAT, but also displaying...subunit ω. This construct is designed to activate transcription from the accessory plasmid (AP) encoding phage...could recognize a library PAM, it would induce transcription of gene III, permitting phage propagation and...spectinomycin resistance. xCas9 3.7 showed the broadest PAM range, recognizing NG, NNG, GAT, and CAA PAMs, while xCas9... xCas9 3.6 displayed the second best PAM range. Characterizing xCas9 in mammalian cells Hu et al. compared...
  33. Golden Gate Assembly Upgrades: More Fragments, Faster Assembly, and Higher Fidelity

    Type
    Blog Post
    Published
    Oct. 11, 2018, 12:30 p.m.
    ...number of transformants); the greater the number of inserts, the lower the number of transformants. To compensate...containing the transformants onto the selection plate. Figure 2 shows representative transformation plates obtained...high levels of transformants and low backgrounds – so much so that there was little range for detectable...the number of transformants while maintaining high levels of correct assemblies) translate to faster assembly...background by antibiotic selection. Screening of transformants by colony PCR confirmed the insertion of the...volume of the 1 ml outgrowth spread on each transformation plate can be manipulated to result in appropriate...
  34. PITChing MMEJ as an Alternative Route for Gene Editing

    Type
    Blog Post
    Published
    Feb. 23, 2016, 3:30 p.m.
    ...genome edits. But have you heard of another double-stranded break repair mechanism: MMEJ (microhomology-mediated...primary methods for repairing DNA after a double-stranded break. HDR copies the sequence from a repair template...are chewed back to reveal homology, allowing the strands to anneal. DNA synthesis then fills in the gaps...5-25 bp) regions of homology flanking a double-stranded break yield precise deletion of the sequence between...locus flanking the GFP-Puro cassette. Three double stranded breaks are necessary for knock-in: one on either...an insertion locus-specific gRNA. These double stranded breaks allow for two sets of microhomologies (...PITCh-gRNA binding sites. This PITCh plasmic is cotransfected with a plasmid carrying Cas9, the PITCh-gRNA...
  35. Light Sheet Fluorescence Microscopy

    Type
    Blog Post
    Published
    July 16, 2015, 2:30 p.m.
    ...microscopy coupled with techniques that make tissues transparent are enabling microscopes to visualize the cellular...the cortico spinal tract, CST, spinal cord and cranial nerve afferents labelled with a AAV8 expressing...sectioning (OPFOS) (2). Arne Voie, David Burns and Francis Spelman focused a laser beam into a thin sheet ...of clear specimens and for in vivo imaging of transparent organisms. Advances in tissue clearing Similar...attempt to render fixed anatomical preparations transparent was done by Walter Spalteholtz (10).  He used...green fluorescent protein (GFP) (6).   The Dodt and Frank Bradke laboratories later developed the 3DISCO (...spinal cords by combining Ultramicroscopy with tetrahydrofuran-based tissue clearing (13,14). A few years ...
  36. Drew Endy Introduces the Biobrick Public Agreement Plasmid Collection

    Type
    Blog Post
    Published
    Dec. 12, 2013, 3:35 p.m.
    ...Science describing the development of “transcriptors,” transistor-like digital genetic switches that enable...comprised of well-characterized bacterial transcription and translation initiation elements. Open science with...dogma - replication of DNA, transcription of DNA to make RNA, translation of RNA to make proteins. That's...reliable gene expression via standard transcription and translation initiation." Nature Methods. 10, 354...cellular computing. These logic gates built from transcriptors are available at Addgene as a BIOFAB kit comprised...genetically encoded sensors. Those sensors could transduce otherwise invisible molecules into regulation ...
  37. How to Design Your gRNA for CRISPR Genome Editing

    Type
    Blog Post
    Published
    Sept. 24, 2020, 1:15 p.m.
    ...-1 Veres A, Gosis BS, Ding Q, Collins R, Ragavendran A, Brand H, Erdin S, Cowan CA, Talkowski ME, Musunuru... efficacious to target the coding or non-coding strand of DNA. As a rule of thumb, we avoid target sites..., 2020). is not limited to single nucleotide transitions but still requires a nearby PAM, although these... modulating gene expression at the level of transcription – CRISPRa (activation) and CRISPRi (inhibition...most-efficacious to target a ~100nt window upstream of the transcription start site (TSS), while for CRISPRi, a ~100nt...of producing the guide (synthetic, in vitro transcription, or lentiviral delivery) can affect the accuracy...examined whenever possible when using knockout or transcriptional modulation approaches. Avoiding off-target ...
  38. AAVs in Retinal Gene Therapy

    Type
    Blog Post
    Published
    July 31, 2018, 12:55 p.m.
    ...and they had been shown to to transduce the retina but only transiently. However new viral vectors capable...adenovirus (AdV) and lentivirus (LV) are known to transduce retinal cells, AAV quickly became the vector of...due to its considerable immunogenicity and its transient expression. LV results in long term expression... in dividing and non-dividing cells due to its (random) integration into the genome, and its large DNA... packaging capacity is well suited for larger transgenes. Unfortunately it has limited tropism in the ...and the one used in Luxturna™, can efficiently transduce various types of retinal neurons. Nowadays a toolbox...engineered AAV serotypes that further expands the range of AAV properties is available. While only natural...
  39. Fluorescent Proteins 101: Green Fluorescent Protein (GFP)

    Type
    Blog Post
    Published
    May 15, 2014, 3:33 p.m.
    ...physiological processes. Re-engineering GFP to increase its range of color and application Almost as soon as its...backbones for constructing fluorescent fusions. Transcription Reporter: Placing GFP under the control of a...promoter in a given cell type. This type of transcription reporting was among the earliest uses of GFP...GFP. Fluorescence resonance energy transfer (FRET): This is used to study the interactions between two ...ion (such as Ca2+) concentrations and pH, using a range of strategies such as FRET, calmodulin, and others... gene of interest, or expressed from the same transcript as the gene of interest, but after an internal...expressing GFP from cells that are not. Developmental/transgenic uses: Because of its stability, GFP can be used...
  40. Antibodies 101: Reading a Flow Plot

    Type
    Blog Post
    Published
    Feb. 6, 2024, 3:13 p.m.
    ...conceptualize where the populations are, try drawing a quadrant over the plot that divides it into four, using...different populations by imagining (or drawing) a quadrant over the dot plot. Created with biorender.com....Biorender! While a helpful visualization tool, a quadrant will often be too clean for real-world data. Most...and debris. The side scatter roughly measures granularity, a proxy for nucleic complexity of the cell.  ...these populations, I suggest using the imaginary quadrant to help (Figure 5). Even though this real-world...real-world data is far messier than biorender plots, quadrants can still help me as a reader if I'm struggling...strategy from Barlow-Anacker et al., 2017, with quadrants to help visualize the different populations. Used...
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