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  1. Opto-Nanobodies: Using Light to Manipulate Cell Signaling and Protein Purification

    Type
    Blog Post
    Published
    Nov. 19, 2019, 2:08 p.m.
    ...loops 1 and 6 resulted in light controlled binding, but with opposite effects: insertion into loop 1 caused...experiments.  AsLOV2 Inertion Site mCherry #1 mCherry #2 GFP Loop 1 dark-induced dark-induced dark-induced...  Option #1: Affinity tag purification You tag YFP and use an affinity column for purification. After binding...and one against GFP. Insertion of AsLOV2 into loop 1 always generated OptoNBs with dark-induced binding... induced dark-induced blue-light induced Table 1: Summary of the effect of AsLOV2 insertion site on...  Light controlled protein purification with OptoNBs The first application for OptoNBs takes us in vitro...light-controlled affinity purification of unmodified proteins. Affinity purification methods typically require...
  2. Truncated gRNAs for Regulating Gene Expression

    Type
    Blog Post
    Published
    Jan. 10, 2017, 3:37 p.m.
    ...while its nucleolytic activity is eliminated (Fig. 1) (1, 3). The gRNA can be further modified by incorporation... Podcast Interview with Alex Chavez Figure 1: Schematic of native (nuclease-competent) Cas9 interacting...which Cas9 protein is directed to which target site (1). Although this is possible, this strategy suffers...sequence or regulating gene expression.     References 1. Esvelt, Kevin M., et al. "Orthogonal Cas9 proteins...target site. Benefits of truncated gRNAs Importantly, the use of truncated guides has largely been demonstrated...protospacer, in the genome. Native Cas9 has two catalytic domains, each of which cleaves one strand of DNA...gRNA (20nt complementarity to target site) or truncated gRNA (≤15nt complementarity to target site). When...
  3. Measuring Kinase Activity at the Single-Cell Level with Kinase Translocation Reporters (KTRs)

    Type
    Blog Post
    Published
    July 26, 2018, 12:46 p.m.
    ...activity in single cells using translocation reporters. Nature protocols, 13 1, 155-169. PMID: 29266096. Find...Kinases: they regulate many proteins, with ~1/3 of human proteins predicted to be phosphorylated on at...which have previously been characterized. See Box 1 in Kudo et al. for more details on the design of the...phosphatase-accessible. Kinase Translocation Reporters (KTRs) Kinase Translocation Reporters (KTRs) are genetically...provides an alternative tool with their Kinase Translocation Reporters (KTRs) whose cellular localization...activity is enhanced, leading to cytoplasmic translocation of the reporter. As a result, the KTR is shuttled...nuclear export and import rates can influence KTR translocation. Work from the Covert lab suggests that these...
  4. Plasmids 101: Modular Cloning Applications and Kits

    Type
    Blog Post
    Published
    May 14, 2024, 1:15 p.m.
    ...Figure 1: A chart with MoClo kit recommendations for different modal organisms and applications.  ...Traditional Biology.” ACS Synthetic Biology, vol. 5, no. 1, American Chemical Society (ACS), 4 Nov. 2015, pp...., vol. 4, no. 9, American Chemical Society (ACS), 1 May 2015, pp. 975–86. Crossref, https://doi.org/10.1021...Yeast Mitochondria.” BMC Biotechnology, vol. 17, no. 1, Springer Science and Business Media LLC, 13 Nov. ...Editing in Plants.” BMC Plant Biology, vol. 20, no. 1, Springer Science and Business Media LLC, 23 Apr. ...Arabidopsis Mutants.” The Plant Journal, vol. 106, no. 1, Wiley, 25 Mar. 2021, pp. 8–22. Crossref, https://...Cloning Platform.” Scientific Reports, vol. 9, no. 1, Springer Science and Business Media LLC, 12 July ...
  5. Pooled Library Amplifications

    Type
    Blog Post
    Published
    May 30, 2024, 1:30 p.m.
    .... Table 1 provides an overview of pooled library protocols you can use as a reference. Table 1: Examples...    Figure 1: Factors to consider when creating a pooled library amplification protocol. Created...etc. The DNA amount can be anywhere from 10 ng to 1 μg of DNA. It often correlates with the size of the...ask for an amplification protocol with your deposit. This is because repeated amplifications of pooled ... an amplification protocol developed for each individual pooled library; generalized amplification protocols...Plasmids Variable Region Size DNA per Amplification Amplification Type Link to Protocol CRISPR Knockout... this blog, we’ll discuss how to develop an amplification protocol for your pooled library deposit. When...
  6. Educational Planarian Tools for Teaching Developmental Biology Techniques

    Type
    Blog Post
    Published
    May 24, 2018, 1:20 p.m.
    ...in situ hybridization experiments. A recent publication [1] from the Sánchez lab describes the plasmids...the deposit) are described in the Sánchez lab publication [1] so that the students performing these experiments...can easily investigate in planarians. References 1. Alice Accorsi, Monique M. Williams, Eric J. Ross,...Proceedings of the National Academy of Sciences 100.suppl 1 (2003): 11861-11865. PubMed PMID: 12917490. PubMed...DE3. For Phagocata morgani and Phagocata gracillis, the process is a little more complicated. These strains...Girardia sp., Dugesia dorotocephala, Phagocata morgani, and Phagocata gracillis. There are 11 different ... coli. Thus, to get the dsRNA into Phagocata morgani and Phagocata gracillis, one has to purify the dsRNA...
  7. Selecting Your Plasmid Purification Kit

    Type
    Blog Post
    Published
    May 27, 2025, 1:15 p.m.
    ...preps, while other applications require large amounts of high quality DNA. Figure 1 illustrates the three... quantity.   Figure 1: Plasmid preps fall into different categories based on their relative qualities...volume ranges of culture as their input (Table 1). When you feel like you need just a bit higher DNA yield...kit for example. These kits are designed to handle ~1–5 mL of liquid culture. Using a higher volume can ...beads and a suitable magnet as you scale up. Table 1: Standard Prep Kit Capacities* Prep size Amount...Amount of culture Approximate DNA yield** Miniprep 1–5 mL 5–50 µg Midiprep 25–100 mL 20–200 µg Maxiprep...column-based DNA purification methods perform well in terms of quality and yield. Bead-based purifications tend to...
  8. PCR Applications for Copy Number Variation Assays

    Type
    Blog Post
    Published
    April 26, 2022, 1:15 p.m.
    ...the determination of amplification of Plasmodium falciparum multidrug resistance-1 gene (pfmdr1). J Parasitol...against the limitations of the assay.      Fig. 1: A schematic representation of Sybr Green chemistry...Methods Mol Biol. 2018;1768:143-160. doi: 10.1007/978-1-4939-7778-9_9. PMID: 29717442. Arya M, Shergill IS...gamma receptor genes FCGR3A and FCGR3B. PloS one, 10(1), e0116791. https://doi.org/10.1371/journal.pone.0116791...run in triplicate.  The nice thing about qPCR is that since it measures relative quantification - that... not need to be run in triplicates. ddPCR is an extremely accurate application, even in areas of the genome...Digital PCR for AAV QuantificationPolymerase Chain Reaction Overview and Applications Resources on Addgene.org...
  9. DNA Purification Without a Kit

    Type
    Blog Post
    Published
    Feb. 11, 2020, 2:15 p.m.
    ...series to increase binding capacity. Figure 1: Purify DNA using glass filters. Image: Kim and Morrison...a gravity-based column plasmid maxiprep kit takes 1-1.5 hours to complete, while this syringe-based method... solution. NaI has two purposes in this protocol: 1) it solubilizes both DNA and agarose, and 2) it helps...property and developed a protocol that uses Whatman No. 1 paper or even paper towels to purify DNA and RNA from... DNA purification without a kit as well as one way to reuse silica columns from DNA purification kits....consider some ways to purify DNA without a kit. DNA purification kits have advantages: they are convenient and...because you’ve run out of columns. Kit-less DNA purification methods avoid many of the drawbacks of kits ...
  10. New Tools Enable CRISPRa for Neuroscience Applications

    Type
    Blog Post
    Published
    July 2, 2019, 12:51 p.m.
    ...by mating with Cre-expressing mice. Figure 1: (A) Schematic of the Cre-dependent SPH construct ... alpha (aCaMKII; excitatory neurons) and Synapsin-1 (pan-neuronal) promoters (Figure 1b), and sgRNAs can...ubiquitous expression of sgRNA(s) and mCherry (vector 1) with neuron-specific expression of dCas9-VPR (Figure...Neuron-specific expression is mediated by the synapsin 1 (SYN) promoter, which was superior in its ability ...genetic underpinnings of these processes has been complicated by the lack of precise genetic tools for modulating...recent advancements and offer commentary on their application to neuroscience research. What is CRISPR-based...accessible to neuroscientists, not all neuroscience applications require such optimized tools. This is elegantly...
  11. Early Career Researcher Toolbox: Social Media for Scientists

    Type
    Blog Post
    Published
    Dec. 11, 2018, 12:46 p.m.
    ... writing for the Addgene blog, sharing Chemistry Cat memes was how I used social media as a scientist....needed to start using Twitter. Sharing Chemistry Cat memes use to be how I used social media as a scientist...how scientists connect on Twitter that I realized 1) a lot of scientists are using social media professionally... but my consistent writing for the Addgene blog (~1-2 blog posts per month) and use of Twitter and LinkedIn... have tips for using social media as a scientist. 1. "5 Ways Scientists SHOULD Be Using Twitter" podcast...of interest. Hopefully through these links, I’ve: 1) convinced you social media can positively impact ...remotely as an Addgene Science Communication Intern. Developing science communication skills, while also learning...
  12. Targeting HIV-1 with CRISPR: Shock and Kill or Cut it Out?

    Type
    Blog Post
    Published
    May 10, 2016, 2:30 p.m.
    ...plasma HIV-1, improving life expectancy and quality for HIV-1 patients. However, ART is not an HIV-1 cure. ...activated HIV-1, measured via HIV-1 promoter-driven GFP expression. In cell lines that can produce HIV-1 toxic...with HIV-1. For two HIV-1 strains, Cas9/gRNA lentiviral expression significantly reduced the HIV-1 copy number...currently infected with the lentivirus HIV-1. Today, HIV-1 can be controlled with antiviral therapies ...HIV-1 transcription and destroy infected cells, the other using wild-type Cas9 to remove the HIV-1 genome...take on HIV-1 in vitro, and what obstacles must be overcome for clinical success. ART and HIV-1 reservoirs...such a therapy, CRISPR/Cas9 would need to 1. excise the HIV-1 genome from every infected cell and 2. prevent...
  13. New Norepinephrine Indicators: nLightG and nLightR

    Type
    Blog Post
    Published
    Dec. 12, 2023, 2:15 p.m.
    ...norepinephrine indicators: nLightG and nLightR (Kagiampaki et al., 2023).     Figure 1: Properties...Article 6. https://doi.org/10.1038/s41592-022-01488-1 More resources on the Addgene blog Fluorescent proteins...after application of NE (10 μM) and corresponding pixel-wise ΔF/F0 heatmaps. White insets indicate surface...surface expression of the indicators over white dashed lines. Scale bars, 10 μm (HEK293T), 20 μm (neurons...trialed in two-photon in vivo experiments. nLight indicators are more sensitive to and selective for norepinephrine...They can, however, be studied with the nLight indicators. Speed One of the major advantages of this next...… Patriarchi, T. (2023). Sensitive multicolor indicators for monitoring norepinephrine in vivo. Nature...
  14. Technique: Probe Phage Genomes for Host Binding Proteins

    Type
    Blog Post
    Published
    Sept. 29, 2016, 2:30 p.m.
    ...wondering what her cat is thinking. Find her on Twitter @JessicaSacher.   References 1. Nobrega, Franklin...which is also gaining a lot of new traction lately (1, 2), depends on knowledge of the structure(s) a given...RBPs successfully identified using this method. Step 1: Prepare a random fragment library of phage DNA This...first step involves digesting phage genomic DNA into 1-3 kb (approximately gene-sized) fragments so that ...in the bulk of resultant fragments falling between 1 and 3 kb results in optimal likelihood of capturing...solution-soaked filter paper (colony-side up) and leave for 1 h at room temperature. After this, it is helpful to...proteins expressed by your library. After blocking for 1 h at room temperature with gentle shaking, gently ...
  15. Quantifying DNA? Here are Five DNA Quantification Methods to Consider

    Type
    Blog Post
    Published
    July 21, 2020, 1:15 p.m.
    ...first before larger fragments. Figure 1: The quantification of a RNA ladder using capillary electrophoresis...automated. Unlike gel electrophoresis, you only need 1-2 ul of sample and the run time is just a few minutes...see any signs of DNA in your final tube after purification. How do you know if you actually have DNA in...you choose could be based on your downstream application, time, and instrument availability. UV absorbance... at 230 nm. The A260/A280 ratio is used as an indicator of DNA purity. Ideally, this number should be ...like a PCR product). This method also gives an indicator of DNA or RNA contamination based on the presence... about quantifying DNA In choosing your DNA quantification method there’s many things to consider: cost...
  16. Scientific Peer-review: Providing Critical and Kind Feedback and Advocating for Open Science

    Type
    Blog Post
    Published
    Aug. 8, 2019, 1:19 p.m.
    ...the journal-specific guidelines.  Peer-review step 1: The first read At the first read of the paper, I ...group of Prof. Mark Tester, where she focuses on (1) salt-induced changes in root-to-shoot ratio in Arabidopsis... to help decide whether work is suitable for publication in their journal. The early peer-review attempts...information that would prevent the study to be replicated or omission from the literature. I think that...Addgene.org Learn about depositing plasmids pre-publication Find molecular biology protocols Find eBooks ...
  17. 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.
    ... Antigen-1 (oriP-EBNA-1) system where each vector contains a viral origin of DNA replication, OriP and...pCXWB-EBNA-1 is used in the reprogramming cocktail. pCXWB-EBNA-1 lacks oriP and is unable to replicate in human...and the EBNA-1 sequence that encodes for the DNA binding protein EBNA-1 [7]. These two sequences are necessary...expressing additional EBNA-1 transiently. The transiently expressed EBNA-1 increases protein expression...pCXLE vectors listed below in Table 1 are available at Addgene. Table 1: List of pCXLE episomal plasmids,...sufficient for retention and replication of the vectors in human cells [8]. The EBNA-1 protein recognizes OriP...obtained and the subsequent reprogramming success [1]. Fibroblasts need to be cultured and expanded in ...
  18. Split Fluorescent Proteins for Studying Protein-Protein Interactions

    Type
    Blog Post
    Published
    May 3, 2022, 1:15 p.m.
    ...General Design Figure 1: Two proteins are fused to the FP(11) and FP(1-10) fragments. When Protein...and 11 to yield large (1-10) and small (11) fragments. In several cases an FP(1-10) fragment may be compatible...Description Article PI Blue EBFP2 EBFP2(1-10) and Capri(1-10) for use with GFP(11) Multiplexed labeling...Commun. 2017 Bo Huang mNeonGreen3 mNG3K(1-10) and mNG3A(1-10) for use with mNG2(11) Improved yellow-...sfCherry2 sfCherry2(1-10) and sfCherry2(11), also photo-activatable variant PAsfCherry2(1-10) Improved split...brings the pieces of the FP back together (Figure 1). This method is generally known as Bimolecular Fluorescence...even from a different base FP (for example, EBFP2(1-10) can be used with GFP(11)). Some of the articles...
  19. Viral Vectors 101: Viral Applications

    Type
    Blog Post
    Published
    April 13, 2023, 1:15 p.m.
    ...several advantages over traditional vaccines, including 1) cellular responses in addition to antibody response...and immunogenicity of attenuated, nef-deleted HIV-1 strains in vivo. Retrovirology. 2007 Sep 23;4:66. ...their use in other clinical applications. In the last decade, viral applications in cancer treatment and ...s unpack the myriad number of emerging viral applications and give you some recommendations for putting...putting viruses to work. Viral applications Viruses work by infecting a host cell (the target of viral infection...expressed. It’s important to note that for all the applications we discuss, there is more than one type of virus...retrovirus, AAV, etc.). When you’ve decided on an application, our Viruses as Biological Tools blog can help...
  20. Transferable Skills Guide: Cross-team Communication

    Type
    Blog Post
    Published
    Nov. 21, 2019, 1:53 p.m.
    ...Addgene, we use seven different types of “plates” (Fig. 1). When you have to tell an engineer that you want ...”? We took steps towards solving this problem by 1) making sure we qualified these words when we discussed.... I needed to a) figure out the sources of miscommunication and b) find practical solutions.  My PhD ... for this task. Good scientists learn how to communicate their work differently based on their audience... family is going to vary widely. The way you communicate your science at a poster is going to vary depending...two main problems with Addgene’s cross team communication. Although these real world examples did not ... for the container to be used in cross-team communication A list of “AKA” names, or jargon terms, for ...
  21. Great Results Start with Great Standard Curves

    Type
    Blog Post
    Published
    Aug. 15, 2024, 1:15 p.m.
    ...    Figure 1: A 1 mg/mL control is diluted in a series ranging from 1:2 to 1:32. Each individual...trendline. R2 ranges from 0 to 1 with 1 being a perfect fit and 0 indicating that there is no linear relationship...example, Figure 1 depicts a 2-fold dilution series. Each step of the series dilutes by 1:2 for a series...series that ranges from 1:2–1:32. The specific dilution series used will depend on the expected concentration...individual step of the series is consistent at 1:2. When preparing a dilution series, use a new pipette tip for... be run in duplicate or triplicate. The closeness of the data points generated by replicate values provides... the standard dilution series in duplicate or triplicate. Replicates allows you to calculate the curve...
  22. Plasmids 101: Common Lab E. coli Strains

    Type
    Blog Post
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    Nov. 7, 2014, 2:56 p.m.
    ...Table 1 below outlines a few of the more common genetic changes found in E. coli strains. Table 1: Common...pooled library amplification. F' mcrA Δ(mcrBC-hsdRMS-mrr) recA1 endA1 gyrA96 gal-thi-1 supE44 λ-relA1 ...amber (UAG) stop codon by tyrosine insertion λ-thi-1 or thi1 Mutation in thiamine metabolism Requires exogenous... all based on E. coli K-12 and are considered BSL-1. Table 2: Lab strains of E. coli Strain Natural...plasmids, blue/white screening. F- endA1 glnV44 thi-1 recA1 relA1 gyrA96 deoR nupG Φ80dlacZΔM15 Δ(lacZYA-argF...) recA13 leuB6 ara-14 proA2 lacY1 galK2 xyl-5 mtl-1 rpsL20(SmR) glnV44 λ- JM109   General cloning and...strain for cloning repetitive DNA. endA1 glnV44 thi-1 relA1 gyrA96 recA1 mcrB+ Δ(lac-proAB) e14- [F' traD36...
  23. Tips for a 1st Time CRISPR User (by a 1st Time CRISPR User)

    Type
    Blog Post
    Published
    March 7, 2017, 3:30 p.m.
    ...of 0.3, as recommended by the original publication. Pro-Tip: 1. Use multiple gRNAs to target different..., as indicated by the presence of a 428 bp digestion product (lane 2). The undigested (-, lane 1) DNA ...The entire process from start to finish took about 1 month. Cas9 delivery Overview: Before any editing...lentiviral vector, lentiCas9-Blast (52962-LV, Figure 1). Some cells were then used to generate a monoclonal...rest of the cells were frozen down. Figure 1: Cas9 expression in A549 cells transduced with lentiCas9...Western blotting is a loading control. Pro-Tips: 1. It’s all about the MOI. In retrospect I used a way... pool had wildly variable Cas9 expression (Figure 1). This is a problem because Cas9 expression affects...
  24. Viral Vectors 101: AAV Variables That Matter

    Type
    Blog Post
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    June 1, 2023, 1:15 p.m.
    ...promoters. Gene Therapy, 28(1–2), 56–74. https://doi.org/10.1038/s41434-020-0169-1 Oh, J. Y., Han, J. H., ...AAV Serotypes and Their Applications in Gene Therapy: An Overview. Cells, 12(5), 1–41. https://doi.org/10.3390...constitutive promoters located in adeno-associated viral vectors. PLoS ONE, 9(8), 1–10. https://doi.org/...the selection process. Factors to think about are (1) your experimental conditions and measurements; (2...serotype, promoter, and titer.     Figure 1: Flow chart depicting a) steps for selecting serotypes...injection site than AAV2 (Watakabe et al., 2015) (Figure 1). You’ll need to consider if such properties could...
  25. CRISPR Between the Genes: How to Experiment with Enhancers and Epigenomics

    Type
    Blog Post
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    Aug. 9, 2016, 2:30 p.m.
    ...chromosome, start, and stop. For instance (chr3, 1, 10) indicates a stretch of DNA at the very beginning of .... Table 1: An emerging family of "GPS for the genome" techniques Technique What It Locates ChIP-seq...clinical applications of CRISPR in the next section. In order to denote the NANOG enhancers from step 1 with...genetic elements like protein, RNA, and DNA (Table 1). As with GPS in the real world, coordinates alone...enhancers with the help of genome math. Figure 1: Genome math illustrated. Intersect (left) and set...histones with “GPS for proteins,” ChIP-seq from Table 1. Because of DNA’s 3D geometry and the chemical properties...experiment to identify the critical NANOG binding sites: 1. Find Enhancers that have NANOG binding sites 2. Design...
  26. Troubleshooting and Optimizing a Western Blot

    Type
    Blog Post
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    Sept. 17, 2024, 1:15 p.m.
    ...the antibody’s dynamic range. Specifically, the 1:2, 1:1, and No dilution samples all have approximately... doing the purification and cross-adsorption in lab, consider a dilution range from 1:100–1:1,000. If ...recommended dilution and/or range (typically between 1:500 and 1:10,000 for primary antibodies). You’ll want to...from ascites fluid, try a dilution range from 1:1,000–1:100,000. Secondary antibodies For secondary antibodies...recommended dilution range is usually between 1:5,000 and 1:200,000. Check the manufacturer’s recommendations...antibodies that are not.   Table 1: Troubleshooting a western blot *indicates a diagnostic-only step Issue...reagent (usually an antibody).      Figure 1: A protein gradient. The density of the bands, which...
  27. Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering

    Type
    Blog Post
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    Dec. 15, 2016, 3:57 p.m.
    ...recombineering system has three components (Figure 1): 1) Exo, 2) Beta, and 3) Gam. All three are required...that occur during DNA replication. There are two ways to avoid activating MMR: 1) use a strain of bacteria...Table 1: Overview of ds- and ss-DNA Uses in Recombineering Substrate Best Suited Application Recombination... interested in science communication and in vitro diagnostics.     References 1. Costantino N, Court DL...from the 5’ end and generate 2 possible products: 1) a partially dsDNA duplex with single-stranded 3’ ...recombineering with an ssDNA oligo substrate.   Figure 1: Components of the Lambda Red Recombineering system...and tags.  The typical frequency of recombinants is 1 positive clone out of 104 to 105 colonies. Pro Tip...
  28. Golden Gate Assembly Upgrades: More Fragments, Faster Assembly, and Higher Fidelity

    Type
    Blog Post
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    Oct. 11, 2018, 12:30 p.m.
    ... assembly reaction** 1 5 min., 37 ºC (2.5 μl) 687 100% 274,200 2,742,000 1 60 min., 37 ºC (2.5 μl)...References 1. Vladimir, Potapov, et al. "Optimization of Golden Gate assembly through application of ligation...expected complete sequence for the lacI/lacZ genes (1), while sequencing of white colonies showed a mixture...representative transformation plates obtained from 1-, 12- and 24-fragment assemblies of the lacI/lacZ ...lacZ cassette, and illustrates how the volume of the 1 ml outgrowth spread on each transformation plate can...fidelity studies conducted by Potapov et al. at NEB (1, 2). While T4 DNA Ligase, the mainstay of most biotechnological...over 90% for 24-fragment assemblies (Figure 3, Table 1). These improvements (5- to 12-fold increases in the...
  29. Typing CRISPR Systems

    Type
    Blog Post
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    March 18, 2025, 1:15 p.m.
    ...   Class 1 versus class 2 There are two CRISPR classes: Class 1 and Class 2. Class 1 CRISPR systems...archaea, though Class 1 remains largely underutilized compared to Class 2. Class 1 Despite their incredible...optimal plasmids to harness the power of Class 1 systems. Class 1 CRISPR systems can be further broken down...and 17 variants. Figure 1: Overview of the CRISPR classification hierarchy. The hierarchy flows...effector complex after binding to a target. Class 1 is the most abundant of the two, comprising about ...incredible abundance, Class 1 CRISPR systems are less popular in the lab. This can be attributed to the multi-Cas...Type I CRISPR systems make up the majority of Class 1, and are the most common type of CRISPR overall. Type...
  30. Antibodies 101: Normalization and Loading Controls for Western Blots

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    Blog Post
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    April 8, 2025, 1:15 p.m.
    ...pipetting or irregular membrane transfer. Figure 1: A loading control is a type of positive control necessary...because the loading control band is weaker in condition 1 than condition 2, the normalized values for the two...to using loading controls accurately. Assumption #1: The loading control is not perturbed by the experiment...without your knowledge? If you can’t trust Assumption #1, any change in the normalized intensity of your POI...interest band is significantly lighter in “condition 1” than “condition 2.” By eye, the loading control appears... the protein abundance axis, both blue “condition 1” points (POI and loading control) are smaller than...assumptions discussed above into question. Assumption #1: The loading control is not perturbed by the experiment...
  31. AAVs CREATed for Gene Delivery to the CNS and PNS

    Type
    Blog Post
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    Sept. 28, 2017, 2:01 p.m.
    ...nervous system (CNS). AAVs are popular tools because: 1) their genomes are easy to manipulate, 2) they have... stained for a neuronal marker). Check out tables 1 and 2 below for a summary of the quantified transduction... AAV vectors. What can these AAV’s be used for?  1. Multi-color labeling of neurons Multi-color labeling... dendrites extend to. The keys to this method are 1) high levels of color diversity so that cells are ...AAV.PHP.eB 69 +/- 4% 55 +/- 7% 76 +/- 5% Table 1: Transduction efficiency of AAV-PHP.B versus AAV-PHP.eB...expression into a two part system (figure 4d):  Part 1: A cocktail of three AAV vectors expressing RGB proteins...neuronal transduction efficiency, as shown in tables 1 and 2, with a cell-type specific promoter or enhancer...
  32. Viral Vectors 101: Voltage Indicators

    Type
    Blog Post
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    Jan. 30, 2024, 2:15 p.m.
    ...depths (1 mm), important for certain applications such as in vivo tissue imaging.   Figure 1: Ace-mScarlet...Voltage indicators are voltmeters for cells! In this blog we will review how these indicators work, their...fluorescence or voltage indicators.   Viral Vectors and Voltage Indicators As previously mentioned...Enhanced genetically encoded voltage indicators advance their applications in neuroscience. Curr Opin Biomed...Cellular communication and function depend on potential energy. Cellular activities like action potentials...their general applications, and why viruses are essential to their use as biological tools. Why Use Voltage...Voltage Indicators? Electrical signals are integral to many facets of biology. For example, many heart...
  33. Viral Vectors 101: Producing Your rAAV

    Type
    Blog Post
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    July 16, 2024, 1:15 p.m.
    ...Inactivation of AAV Serotype 1 Vectors. Human Gene Therapy Methods, 28(1), Article 1. https://doi.org/10.1089...Figure 1).    Figure 1: Overview of key steps of AAV production, iodixanol gradient purification, and ...repeat sequences. Human Gene Therapy Methods, 23(1), Article 1. https://doi.org/10.1089/hgtb.2011.034 Benyamini...in the CNS. Molecular Neurodegeneration, 15(1), Article 1. https://doi.org/10.1186/s13024-020-00361-z ...lentivirus, AAV does not possess the ability to replicate itself and depends on helper viruses like adenovirus...herpes simplex virus to facilitate efficient replication. The most common production system, however, ...RNA genes; and the pRepCap plasmid containing replication factors and serotype-specific capsid genes.  ...
  34. Who Gives a Tweet? 9 Facts About Scientists on Twitter

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    Blog Post
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    June 26, 2017, 1:31 p.m.
    ...2017. 1. Among scientists, historians have the most Twitter users. Biologists rank #8. Figure 1: Highly...that these results could be biased for two reasons: 1) they are based on the US Occupational Employment ...female to male = 0.629 (the closer this ratio is to 1, the closer males and females are to parity - the ... authorship in the United States (0.428). 4. The #1 (re)tweeted domain by scientists was Instagram Social...links to research that isn’t behind paywalls. 5. The #1 (re)tweeted science domain by scientists was Nature...mostly because of this article: “A systematic identification and analysis of scientists on Twitter.” This...from the United States Standard Occupational Classification System  and Wikipedia. 2. Social and computer...
  35. The Effect of COVID-19 on Liu Lab Plasmid Requests From Addgene Data

    Type
    Blog Post
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    July 16, 2020, 1:15 p.m.
    ...we observed one complication in the China data – there is a period of 1 month, from 1/22/20–2/23/20, where...was around 33% of that observed between Jan. 1 and Mar. 1, 2020. Figure 2: A simple approximation...paper. Green and red lines depict the sum of mean +1 and -1 std for each paper, respectively. The fitted...plasmid requests correspond to publications of popular papers. Figure 1: Plasmid requests by date. ... from 5/22/14 to 5/19/20). Each paper has between 1–32 plasmids and a total of 2–2,590 requests. We received...China. However, it is evident that if we believe that 1/22/20–2/23/20 are the more accurate dates of lockdown...subfields.  Plasmid requests correlate with paper publication The dataset includes 11,426 plasmid requests ...
  36. MXS Chaining

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    Blog Post
    Published
    Feb. 7, 2017, 3:30 p.m.
    ...assembly. Journal of biological engineering. 2010;4(1):1. Pubmed PMID: 20205762. PubMed Central PMCID: PMC2822740...with minimal spectral overlap between them (Table 1). In each construct, 3 copies of the fluorescent protein... enabled labeling of particular structures (Table 1). Each construct was flanked with a CMV promoter (...construct was then introduced to HeLa cells (Figure 1). The resulting HeLa cells show robust labeling, with...fluorophore at the respective subcellular structure (Figure 1). Here, MXS Chaining gave researchers the ability ... all four constructs into one 15 kb insert. Table 1: MXS Constructs for Labeling Cellular Structures ...maxima Tethering partner Subcellular localization 1 TagBFP 399nm/ 456nm histone 2B (H2B) Chromatin 2...
  37. Recombinase-based State Machines Enable Order-dependent Logic in vivo

    Type
    Blog Post
    Published
    July 28, 2016, 2:30 p.m.
    ...RSM (See performance data from the indicated figures in our paper (1)) Input Plasmid Output Plasmid Fig... S9 of our paper (1)). We anticipate that, depending on the context and application, some inducible recombinase...recombinase-based state machines in living cells” (1), into a more straight-forward, concise explanation...an RSM is to sequence the register. In our paper (1), we allowed individual bacterial cells to form colonies...in the Materials and Methods section of our paper (1). Lastly, it is possible to build gene regulatory ... not. How might one implement RSMs? In our study (1), we implement RSMs in E. coli with two plasmids (...inputs to endogenous gene expression (2). Our paper (1) explains how to arrange attB-attP pairs on a register...
  38. Adenoviral Vector Production and Troubleshooting

    Type
    Blog Post
    Published
    June 14, 2018, 11:44 a.m.
    ...incubation as it will result in very low titer. Amplification (1-2 weeks) - The rAdV-S is used to infect more...increasing scale over the course of 1-2 weeks. Each round of amplification should result in a 10-100-fold ...repeats (ITR) present at both ends.   Figure 1: A) The structure of an adenovirus: the virion is ... 5 key steps: Construction of the rAdV plasmid (~1 week): The AdEasyTM system is the most popular method...Addgene’s Adenoviral Guide webpage, and references 1, 2.*Pro-Tip*: once the correct recombinant pAdV plasmid...transfected with the AdV plasmid construct from step #1 and allowed to stay in culture for up to 20 additional...CsCl are commercially available. Titer calculation (1 or 10 days) Physical titer (particle count, rAdV genomes...
  39. Live and Let Dye: Self-Labeling Protein Tags

    Type
    Blog Post
    Published
    April 16, 2024, 1:15 p.m.
    ...imaging of intracellular targets. Nature Communications, 7(1), Article 1. https://doi.org/10.1038/ncomms10778...by modular envelope design. Nature Communications, 14(1), Article 1. https://doi.org/10.1038/s41467-023...formin and capping protein. Nature Communications, 14(1), Article 1. https://doi.org/10.1038/s41467-023...molecules in vivo. Nature Biotechnology, 21(1), Article 1. https://doi.org/10.1038/nbt765 Lavis, L. (2016...Few Complicated Non-natural amino acids 1 Various Many Complicated   Applications Organic...fluorescent proteins, opening up new applications.   Figure 1: Live-cell labeling strategies. The...up linked to whatever molecule you choose (Figure 1). Just express the fusion protein and add a specific...
  40. Important Considerations When Using AAVs

    Type
    Blog Post
    Published
    June 13, 2017, 2:30 p.m.
    ...Viral Vector Blog Posts from Addgene 1. Location, location, location! What do buying real estate and using...important factors related to location. Location (1): What tissue? Location (2): Where in the tissue/which...vectors without specific facilities (Biosafety Level-1). Other possible tools, lentiviruses for example, ...suspected cases of insertional mutagenesis in humans (1) and AAVs are non-enveloped viruses, so they are resistant...the right serotype? Keep asking questions!  Table 1: AAV Serotypes and Tropism Experiment  Detection...the vicinity of the injection. Examining serotypes 1, 8 and 9, not only do they undergo retrograde and ...types of research may be enabled by the use of AAVs? 1) Combined functional and anatomical mapping of circuits...
  41. Antibody Validation for Flow Cytometry

    Type
    Blog Post
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    Sept. 10, 2024, 1:15 p.m.
    ...dye, respectively. WT and KO cells were mixed in a 1:1 ratio and fixed in 4% PFA and permeabilized in 0.1%...antibodies were diluted to 1 µg/mL except for 14558, which was used at 0.35 µg/mL (1/100). * = monoclonal antibody...through their HLDA workshops. Let’s use TIM-1 (Single pass type-1 membrane protein), which has been designated.... 400,000 cells were stained with the indicated Synaptotagmin-1 antibodies and corresponding Multi-rAb...specific antibody:target combination of interest (Figure 1). It can therefore be helpful to try all three when...to label an intracellular target.   Figure 1: HCT 116 WT and SYT1 KO cells were labelled with a...between the wild-type and the KO population (Figure 1), further optimization can be performed to both maximize...
  42. Lentiviral Vector Uses and Overview

    Type
    Blog Post
    Published
    May 19, 2016, 2:30 p.m.
    ...HIV-1 were transduced with a lentiviral vector containing an antisense sequence against the HIV-1 envelope...Trono and collaborators turned to the lentivirus HIV-1, well-known to infect non-dividing cells. The first...plasmids. The packaging plasmid carried a mutated HIV-1 provirus that couldn’t package itself due to a few...plasmid encoded the desired transgene flanked by HIV-1 long terminal repeats (LTRs) that facilitate viral... targeting and tracing cells in the brain (Figure 1). 2nd generation lentiviral packaging system The graphic...infectivity, is often used as a substitute for HIV-1 Env, which can only infect CD4+ cells. 3rd generation...lentivirus in the comments section below! References 1. In vivo gene delivery and stable transduction of ...
  43. X-CHIME: Context Dependent Germline Knockout in Immune Cells

    Type
    Blog Post
    Published
    Jan. 16, 2024, 6:13 p.m.
    ...in the immune system. Nature Immunology, 25(1), Article 1. https://doi.org/10.1038/s41590-023-01689-6 ...screening of genes in the immune system. Nature Communications, 10(1), 1668. https://doi.org/10.1038/s41467-019... strains and lentiviral expression vectors (Table 1). The four systems Name Function Plasmid ... GFP (vex) Rosa26-FlpO-ERT2; H11-Cas9 Table 1: X-CHIME systems Proof of Concept These systems were...was lethal (LaFleur et al., 2024).   Figure 1: Schematic showing the X-CHIME approach. Figure from...
  44. Degrading DNA with Cascade-Cas3

    Type
    Blog Post
    Published
    Feb. 11, 2025, 2:15 p.m.
    ...Cascade's complexity. Figure 1: Schematic of Class 1 CRISPR types. Class 1 includes type I with a Cas3 ...up type I, the most abundant type in the Class 1 category. These type Is can then be further broken into...unidirectional genome editing in human cells. Nature Communications, 10(1). https://doi.org/10.1038/s41467-019-13226...collection! A “complex” system Cas3 is part of the Class 1 CRISPR family, which means it requires multiple Cas...the brunt of the mechanical work for editing. Class 1 CRISPR systems make up the majority of CRISPR-based...CRISPR-based immune systems in bacteria and archaea. Class 1 is further broken down into different types, with ...antiviral defense). Cascade is brought to the target location using a gRNA and can then recruit Cas3, which ...
  45. The Breast Cancer Microenvironment: A Tumor’s Backstage Team

    Type
    Blog Post
    Published
    Jan. 31, 2019, 1:32 p.m.
    ...enzyme (among others): caveolin 1, also known as CAV 1. Usually, caveolin 1 promotes the cell life cycle ...caveolin 1, there’s less malignancy because there’s less proliferation. However, the lack of caveolin 1 in ...believes that miRNA may decrease the expression of TAK 1, an enzyme that controls apoptosis and regulates transcription...Agnieszka K., et al. "An absence of stromal caveolin-1 expression predicts early tumor recurrence and poor... these stromal cell modifications, stromal cells are also constantly communicating with a tumor, proving... was contributed by Bárbara Pinho, a science communicator at the Portuguese science museum "Fábrica Centro...Proficient in transportation, exosomes are tools of communication and provide malignancy to the microenvironment...
  46. Viral Vectors 101: The Retroviral Lifecycle

    Type
    Blog Post
    Published
    July 27, 2023, 1:15 p.m.
    ...can use Figure 1 to compare the genomes of these two family members.   Figure 1: Gamma-retrovirus...Retroviruses” is an umbrella term which encompasses 1.) the gamma-retroviruses — that have been developed...of retroviruses called the lentiviruses (like HIV-1) — that have been developed into lentiviral vectors...Academy of Sciences of the United States of America, 54(1), 137–144. https://doi.org/10.1073/PNAS.54.1.137. ...1997). Functional RT and IN incorporated into HIV-1 particles independently of the Gag/Pol precursor protein...RNA as template. Journal of Molecular Biology, 79(1), 163–183. https://doi.org/10.1016/0022-2836(73)90277...Aids Full-Length Human Immunodeficiency Virus Type 1 DNA Synthesis. Journal of Virology, 82(5), 2376. https...
  47. Mouse Modeling, Part 2: Breeding and Crossing Mice

    Type
    Blog Post
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    Aug. 6, 2019, 12:55 p.m.
    ...approximately 1 in 16 mice that harbor homozygous alleles at both of your genes of interest. About 1 in 4 mice...inheritance: 1. Genotype your parental mice In order to ensure that your genetic modification will be passed...In Part 1 of our mouse modeling blog series, we covered techniques that can be used to introduce genetic...mice in your experiment. As you’ve learned in Part 1, there are many types of genetically engineered mice...example of mice that are derived from crosses. In Part 1, we explained how genetic recombination in mice expressing...expressed, or inducible (this is explained more in Part 1 of this series). In any case, Cre is a dominant phenotype...genetic modifications into mouse embryos. But once you generate a growing colony of genetically engineered...
  48. When is a Monomer not a Monomer? The Top Three Ways Your Favorite Fluorescent Protein Oligomerizes in Cells

    Type
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    Published
    April 19, 2016, 2:30 p.m.
    ...Figure 1).   Figure 1: Each problem with dimerizing fluorescent proteins is illustrated. 1) Membrane... in nature are prone to dimerization (i.e. EGFP) [1, 2] or even form obligate tetramers (i.e. DsRed) [...active state due to closure by FP dimerization.   1. Transmembrane fluorescent protein fusions Transmembrane...bright, non-physiological, and difficult to ignore [1, 2]. 2. Fusion to an obligate dimer or oligomer Several... For a more detailed discussion see [5]. Problems 1 and 2 depend on protein concentrations. An imperfect... distance runner, gardner, and cook.   References 1. Snapp, E.L., et al., Formation of stacked ER cisternae...problem for fusion proteins. One of the major applications of FPs is to visualize the localization, dynamics...
  49. Viral Vectors 101: Integrase-Deficient Lentiviral Vectors

    Type
    Blog Post
    Published
    May 13, 2025, 1:15 p.m.
    ...and no viral progeny are produced (Figure 1).  Figure 1: Comparison of the life cycle of a lentiviral...2004). HIV-1 gene expression: lessons from provirus and non-integrated DNA. Retrovirology, 1, 13. https... cannot integrate it into the host genome (Figure 1). IDLVs were first discovered by researchers investigating...you might choose an IDLV over a lentiviral vector: 1. No risk of insertional mutagenesis Lentiviral vectors..., H. E. (1996). Human immunodeficiency virus type 1 integrase mutants retain in vitro integrase activity...Berry, C., Ecker, J. R., & Bushman, F. (2002). HIV-1 integration in the human genome favors active genes...https://doi.org/10.1186/1742-4690-1-13. PubMed PMID: 15219234 PubMed Central PMCID: PMC449739 Yew, C.T., ...
  50. Addgene Depositors Get More Citations

    Type
    Blog Post
    Published
    April 20, 2017, 2:30 p.m.
    ...the journal of publication. Table 1 provides an example calculation of the weights. Table 1: Journal Weighting...amassed nearly 2,400 citations in its first four years (1). In addition to publishing in Science, Professor ...papers without plasmids deposited with Addgene (Figure 1). Even aggregated this much, you can see the 2013...(F) Weight (=F/E) (G) Weighted Citations (=C*G) 1 2010 3 Nature  3.3% 10.5%   3.2  9.6 2 2010...website at: http://www.neil-t.com/ .   References 1. Cong, Le, et al. "Multiplex genome engineering using...databases available, Web of Science. For each publication, Web of Science provides basic bibliographic ...Science, PLOS One, and PNAS. We then broke the publications from these journals into two groups: those containing...
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