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  1. Getting to Know Expansion Microscopy

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    Blog Post
    ...protocols. A typical ExM protocol (Fig. 1) follows this structure: Step 1: fix (and maybe label) your sample...microscopy. Nat Biotechnol 1–12. https://doi.org/10.1038/s41587-022-01546-1  Mikhaylova M, Cloin BMC, ...just adding water.)  Step 5: Image   Figure 1: The ExM process allows you to physically magnify ...16:71–74. https://doi.org/10.1038/s41592-018-0238-1  Klimas A, Gallagher BR, Wijesekara P, et al (2023...Microscopy. What is Expansion Microscopy?  ExM provides a straightforward answer to the space problem....improve label density (Mikhaylova, et al. 2015).  Despite these limitations, ExM is a valuable tool, especially...Bournonville L, et al (2021) Expansion microscopy provides new insights into the cytoskeleton of malaria ...
  2. A Primer on Optogenetics: Introduction and Opsin Delivery

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    ...Jacqueline N Crawley  [et al]. 2012;Chapter 1:Unit 1 20 1-18. doi: 10.1002/0471142301.ns0120s59. PMID:...mutually exclusive) commonly used in optogenetics: 1) electrophysiology and 2) behavioral experiments. ...can be broken down broadly into three main steps: 1) Selection and expression of your opsin of choice ...reviews for a discussion of the different variants [1, 2, 4]. And, of course, the best way to learn about...monitor expression at various time points (e.g. every 1-2 weeks over 8 weeks) in order to determine the optimal...follow him on Twitter @derekpsimonphd.    References 1. Tye KM, Deisseroth K. Optogenetic investigation of..., Jacqueline N Crawley  [et al]. 2013;4(435):4 35 1-4  20. doi: 10.1002/0471142301.ns0435s65. PMID: 25429312...
  3. Twenty Years of Sharing: Expanding Accessibility

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    ...is right for their experiment.     Table 1: Most popular guides, protocols, and collections of 2023. ...our repository to an amazing 111 countries (Figure 1)! But while we were making the materials available...accessibility varied country to country.   Figure 1: Number of countries Addgene distributes to per year...date, we have partnered with six distributors (Table 1), in China, Korea, Japan, Brazil, India, and Mexico...in 2023, from visitors in 218 countries. In Table 1, you can see our most popular educational resources... execute a step can provide needed clarity (Table 1). Our most popular video, however, is “What is a Plasmid...shipping. However, there were issues that persisted despite our best efforts. With a little over half of our...
  4. Plasmids 101: FLEx Vectors

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    ...coding sequence in the antisense orientation (Figure 1, top). The entire DNA cassette would be flanked by...include both Cre and FLP recombinases.   Figure 1 (modified from Schnutgen et al. Nat Biotech 2003):...identical sites on one end of the DNA fragment (Figure 1, middle). A second recombination event then excises...between the identical loxP or lox511 sites (Figure 1, bottom). Since only one loxP and lox511 site will...genOway press release for more information. References: 1. Schnütgen F, Doerflinger N, Calléja C, Wendling O...switches? FLEx (or “flip-excision”) switches were designed as a genetic tool for researchers to conditionally...does the FLEx switch work? Let’s say you want to design a genetic FLEx switch that turns BFP expression...
  5. Making CRISPR Plasmids Using Fragmid

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    ...Table 1 has a list of Fragmid destination vectors currently available. Table 1: Fragmid destination vectors... Let's walk through designing a CRISPR vector the Fragmid way!    Figure 1: Selecting your vector...answers in step 1, so you’ll only be able to select components that work with your design. Note that you...components on the Fragmid website.   Figure 1: (Top) Schematic overview and timeline of the Golden...website, which breaks the design process down into four easy steps, provides the real value for the user...potential of them not working, or spend a few weeks designing and cloning the vectors you actually want. But... Fragmid is a modular vector assembly process designed for a quick, plug-and-play approach to cloning...
  6. Antibodies 101: Producing Recombinant Antibodies

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    ...materials have been washed away (Figure 1).      Figure 1: The steps of rAb production. Created ...EBNA1 Cells. Methods Mol Biol. 2018;1850:1-16. doi: 10.1007/978-1-4939-8730-6_1. PMID: 30242676. Frenzel...Neuroscience Research. Curr Protoc Neurosci. 2020 Dec;94(1):e106. doi: 10.1002/cpns.106. PMID: 33151027; PMCID...detection, and control. Int J Pharm. 2018 Oct 25;550(1-2):251-268. doi: 10.1016/j.ijpharm.2018.08.043. Epub...case, a buffer exchange can be performed using a desalting column or an ultrafiltration concentrator. As ...suggests, you may also concentrate your prep to the desired concentration using these columns. If you are conjugating...
  7. Multiplex Genome Editing with CRISPR-Cpf1

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    ...For these experiments, cells were infected with a 1:1 ratio of two AAVs,  one expressing Cpf1 and the other...comparison of Cpf1 vs. Cas9, see the table below. Table 1. Comparing the Cas9 and Cpf1 CRISPR Nucleases   ...Overall, these approaches have two main drawbacks: 1) Most rely on transfection of more than one vector...leave them in the comments below.        References 1. Zetsche et al. "Multiplex Gene Editing by CRISPR–...editing!  A recent paper from Feng Zhang's lab describes how to use Cpf1 for multiplex genome editing.  ...sequence NGG TTTV PAM site preserved? Usually Destroyed Yes, Cpf1 cleaves 5' of the protospacer Multiplexing....  Similar to a jigsaw puzzle, the oligos were designed with sticky ends that only anneal together in ...
  8. Using AAV for Neuronal Tracing

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    ...but also others including pseudorabies virus type 1, vesicular stomatitis virus (VSV; Beier et al., 2011...Skeletal Muscle AAV1, AAV6, AAV7, AAV8, AAV9 Table 1: Common AAV Serotypes and their target tissues (adapted... serotypes capable of entering neurons (see table 1)(Choi et al., 2005; Taymans et al., 2007; Howard et...efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain. PLoS One 8:e76310...Wolfe, J.H. (2014). Adeno-associated virus serotypes 1, 8 and 9 share conserved mechanisms for anterograde...,9 in rat neurons and glia in vitro. Virology 372(1), 24–34. PubMed PMID: 18035387. PubMed Central PMCID...transduction efficiency of recombinant AAV serotypes 1, 2, 5 and 8 in the rat nigrostriatal system. J Neurochem...
  9. How-to: 5 Steps to a Great Panel Discussion

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    ...not let the panelists introduce themselves. I do a 1-2 minute introduction. If you chose good panelists...take 5 minutes to introduce themselves and, voila, 1/2 of your time is gone with no interesting discussion...introductions. The moderator asks questions, calling on 1-2 panelist for each question in a way that elicits... time you are at a talk and the speaker goes over 1 hour, watch what happens to the attention of the audience...postures shift, they are checking out. If you can, plant 1-2 good questions with trusted audience members. A ... asking the panelists not to use any slides for the event. Slides are for presentations, not discussions...discussions. I will rarely work with a panel if slides are allowed. Don't put your panelists behind a table. ...
  10. Which Fluorescence Microscopy Techniques is Best for Me?

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    ... in modern biology (1). When performed correctly, fluorescence microscopy provides a high contrast image...relatively thicker three dimensional sample (see Figure 1); similar to an MRI or CT scanner. This is accomplished... the resolution of a light microscope (see Figure 1). What microscopy technique should I use for my experiment...new sample I always start by asking two questions: 1) Is the sample dynamic or static? 2) Is the sample...of modern day fluorescence microscopes (see Table 1). Thin dynamic samples Ex: monolayers of live cells...excitation light can push imaging depths closer to 1 mm. Traditionally, 2-photon has been a very slow imaging...manufacturers have similar information References 1. Lichtman JW, Conchello JA. Fluorescence microscopy...
  11. Viral Vectors 101: Pseudotyping

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    ...disadvantages: Table 1 (Joglekar et al., 2017)  Table 1 (Gutierrez-Guerrero et al., 2020) Table 1 (Cronin et al...polyA tail.   Figure 1: Lentiviral production uses three plasmids: (1) The transfer plasmid, (2)...can be used for specific purposes as described previously (Table 1, Gutierrez-Guerrero, et al, 2020). Because...pseudotyping allows these viruses to infect neurons. Besides altering the host tropism of your virus, there ...neurons. However, VSV-G’s broad tropism can be undesired for in vivo studies since there’s the potential...VSV-G is also toxic at high concentrations as described above and is inactivated by the complement system...
  12. AAV Packaged on Request is Here!

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    ...it, select your desired serotype and volume, and submit your request.    Figure 1: The AAV Packaged..., AAV8, or AAV Retrograde (AAVrg), and volumes of 1 mL, 2.5 mL, or 5 mL. Please note that all orders will... our on-demand viral service, we expect titers of 1 × 1013 GC/mL for AAV1, AAV5, AAV8, and AAVrg and 7...simply request your plasmid of interest in your desired serotype, place your order when ready, and we’ll...
  13. Deep Dive: qPCR

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    ... Table 1: Features of various qPCR chemistries. Adapted from Wong, 2018   Primers Design of primers...relatively easy to multiplex (Thellwell, 2000). See Table 1 for a comparison of features of several commonly used...show multiple peaks.    (a) (b)  (c)   Fig. 1: Melt curves showsing (a) a single peak, indicating...changes in ΔΔCT are represented by RQs between 0 and 1. Flipping your experimental and control values during...see this fold change as a positive difference (RQ>1), which may be easier to conceptualize. Just remember... in Molecular Biology, vol. 1160, DOI 10.1007/978-1-4939-0733-5_3, © Springer Science+Business Media New... application, Bioinformatics, Volume 27, Issue 7, 1 April 2011, Pages 1019–1020, https://doi.org/10.1093...
  14. Sleeping Beauty Awakens for Genome Engineering

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    ...been designed to perform gene transfer in vertebrates. The system is comprised of 2 components: 1) an ...use is only likely to grow in the coming decades.  References 1. Kowarz E, et al. Optimized Sleeping Beauty...also important for social and regulatory reasons. 1.) The transposon consists of a mirrored set of inverted...T cells to target CD19. Immunol Rev. 2014 Jan;257(1):181-90. doi: 10.1111/imr.12137. PubMed. Find the ...
  15. Optimizing Donor DNA for Enhanced CRISPR Genome Editing

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    ... Figure 1 below) was free to anneal to complementary ssDNA molecules in vitro. Figure 1: Cas9 binding...allowed sequence replacement rates of approximately 1%. This is by no means a large number, but it was attained...who worked on this publication:         References 1. Richardson, Christopher D., et al. "Enhancing homology-directed...DNA post-cut. Using substrate DNA labeled on both sides of the break, we determined that Cas9 held tightly... single or double stranded donor DNA with other design parameters. Example single stranded donor DNA and...approaches. Moreover, the cost of reagents is relatively modest, requiring expressed Cas9 protein, transcribed ... Blog Brush Up on Your HDR Basics Learn How to Design Your gRNA Find the Ideal CRISPR Software for Your...
  16. Tips for Titering Your Lentiviral Preps

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    ...type of assay is a clonal cell line known to contain 1 integrated copy of the qPCR target gene. Developing... successful transduction experiment. References 1. Kutner, Robert H., Xian-Yang Zhang, and Jakob Reiser...Production, concentration and titration of pseudotyped HIV-1-based lentiviral vectors."Nature protocols 4.4 (2009... titration methods."BMC biotechnology 6.1 (2006): 1. PubMed PMID: 16836756. PubMed Central PMCID: PMC1534021...events." Genetic vaccines and therapy 2.1 (2004): 1. PubMed PMID: 15291957. PubMed Central PMCID: PMC514534...virus will not only ensure that your infection is designed in the best possible way, but it may also save...the transgene itself. Many researchers prefer to design primers that target the common features of viral...
  17. PiggyBac-ing Through the Genome Editing Field

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    ...Correct Path.,” J. stem cell Regen. Biol., vol. 1, no. 1, Jan. PubMed PMID: 26702451. PubMed Central PMCID...genetic manipulation in mammalian cells until 2005 [1]. Like other transposons, piggyBac™ has two components...The predicted frequency of ‘TTAA’ in the genome is 1 in every 256 base-pairs of DNA sequence, making it...has been demonstrated) with no known upper limit [1]. The piggyBac™ technology can be used for numerous...genetic loci of integration [8].   Figure 1: Mechanism of the piggyBac™  transposase/transposon...technologies and strategies for their projects. References 1. L. E. Woodard and M. H. Wilson, “piggyBac-ing models...facilitate the selection of cells containing your desired edit. The selection is marker is then seamlessly...
  18. Celebrating Outstanding CRISPR/Cas9 Achievements at the Dr. Paul Janssen Award Dinner

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    ...minutes, which was fun to watch. A simpler 1 protein - 1 RNA system Drs. Dounda and Charpentier met at...to direct cleavage the result was a simpler 1 protein - 1 RNA system.  Dr. Charpentier advocated for the...with genes knocked out in the insulin signaling cascades in only 4 months compared to a year or greater...
  19. Adeno-associated Viruses (AAVs) for Genome Editing

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    ...infection, gene targeting vectors with relatively short (1 kb) homology arms underwent homologous recombination...sequences of interest to cells with efficiencies of 1-40% after G418 selection (Kohli et al 2004, Kim et...with polylinkers for the addition of gene-specific 1 kb homology arms flanking a FLOXed neoR gene. pAAV-SEPT-Acceptor...since it routinely generates knockin efficiencies of 1-40% with G418-selected clones. However, there are ...efficiency of gene editing is occasionally less than 1%, and virtually never exceeds 40%. While this is comparable...gene inactivation in human cancer.     References 1. Russell, David W., and Roll K. Hirata. "Human gene...human cells (Kim et al, 2016). The Waldman lab has designed their AAV tagging vectors (pAAV-SEPT-Acceptor ...
  20. Truncated gRNAs for Regulating Gene Expression

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    ...while its nucleolytic activity is eliminated (Fig. 1) (1, 3). The gRNA can be further modified by incorporation...introduce a desired genetic alteration. Listen to Our Podcast Interview with Alex Chavez Figure 1: Schematic...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...genetic locus when complexed with an appropriately designed small RNA, or guide RNA (gRNA). The gRNA conventionally... truncated such that it exhibits 15 or fewer nucleotides of complementarity to a target site, Cas9’s DNA...truncated gRNAs Importantly, the use of truncated guides has largely been demonstrated to result in decreased...
  21. Simple CRISPR-based Epigenetic Editing: dCas9-directed DNA Demethylation

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    ...modifications). Ready to get started?   Figure 1: Break free from the ball and chain!   Epigenetics...?  Dividing cells depend on DNA methyltransferase 1 (DNMT1) to copy methylation marks from parental to...doi.org/10.7554/eLife.34870.  Kaas GA, Zhong C, Eason DE, Ross DL, Vachhani RV, Ming G-L, King JR, Song H,...Recently, however, a particular tool has gained widespread popularity – and notoriety – as a tool of choice...leave you with a few practical considerations: Design your gRNA to overlap the CpG of interest. Having..., too), but if this is not possible due to gRNA design restrictions, anything within 5 base pairs should...
  22. Adapting Toehold Switches to Detect Zika Virus

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    ...Green, Alexander A., et al. "Toehold switches: de-novo-designed regulators of gene expression." Cell 159.4...detects samples at clinically relevant concentrations (1-3 fM; 1x106-fold lower than before), and our combined... health, energy, and sustainability.   References 1. Pardee, Keith, et al. "Rapid, Low-Cost Detection ...Specifically this includes primer directed isothermal RNA amplification, new toehold switch designs, CRISPR/Cas9...is an Assistant professor at the Biodesign Center for Molecular Design and Biomimetics and the School of...development of diagnostics. Mostly transmitted by Aedes mosquitoes (aegypti and albopictus) and, aided by... toehold switches, which allow for the rational design of RNA sensors that can detect virtually any RNA...
  23. Viral Vectors 101: AAV Serotypes and Tissue Tropism

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    ...them to target particular cell types. Figure 1: Diagram of AAV components. Created with BioRender.com...depends on your choice of promoter/enhancer. Table 1: AAV capsids and receptors. Capsid Primary receptor...required)2 Human fibroblast growth factor receptor 1 (FGFR1)3 αVβ5 and α5β1 integrins3 Hepatocyte growth...structure of AAV2, so they are formally called rAAV2/1, rAAV2/2, and so on, although we often use abbreviated...efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain. PloS One, 8(... N.J.), 807, 141–157. https://doi.org/10.1007/978-1-61779-370-7_6 Tabebordbar, M., Lagerborg, K. A., Stanton... and Transduction by Adeno-Associated Virus Types 1 and 6. Journal of Virology, 80(18), 9093–9103. https...
  24. Measuring Kinase Activity at the Single-Cell Level with Kinase Translocation Reporters (KTRs)

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    ...been characterized. See Box 1 in Kudo et al. for more details on the design of the bNLS and NES sequences...Kinases: they regulate many proteins, with ~1/3 of human proteins predicted to be phosphorylated on at...using translocation reporters. Nature protocols, 13 1, 155-169. PMID: 29266096. Find the KTR plasmids here...reporters are challenging to design and difficult to multiplex. The Covert Lab provides an alternative tool with...fluorophores can be multiplexed together. Challenging  to Design: FRET reporter activity depends on both the distance...advantages. First, they are easy to multiplex. Their design allows flexible swapping of fluorescent proteins...overlap are used together. Second, KTRs are easy to design. The key determinants of KTR function are the positions...
  25. Droplet Digital PCR for AAV Quantitation

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    ...range of titers. We usually dilute our samples 1:6 million to 1:25 million.  After making the dilutions, they...note that the dynamic range of the ddPCR is between 1 and 100,000 genome copies (GC) per reaction. Since...In the image to the right, there is approximately 1 positive copy per microliter in the no template control...elongation time to 2 minutes and the denaturation time to 1 minute has been shown to increase droplet separation...diagnosis." Emerging microbes & infections 7.1 (2018): 1-9. PubMed PMID: 29691363. PubMed Central PMCID: PMC5915492... to a new plate containing the mastermix which includes primers and a ddPCR supermix. Note that the supermix...
  26. Google Forums Round Up: First Impressions of NgAgo

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    ...the genome, which seem resistant to Cas9 cleavage (1). Both the CRISPR-Cas9 and NgAgo genome engineering...it was first published in Nat Biotech in May 2016 (1), NgAgo has received much attention and the plasmid...Pooran's NgAgo Survey Survey results As of August 1, 2016, a total of 165 researchers responded to the...the cell, the same method used by Gao et al, 2016 (1). View the Complete and Up-to-Date Results of Pooran's... dreams of a sunny day in Edinburgh.   References 1. Gao, Feng, et al. "DNA-guided genome editing using...researchers must co-transfect cells with 5’-P-ssDNA guides and an NgAgo expression plasmid to edit a gene ...Try NgAgo for Yourself On the other hand, the widespread success of CRISPR-Cas9 across multiple model ...
  27. Pathways Over Time Plasmids Engage Students in Functional Genomics Research

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    ...undergraduate students (1, 2), but educators face significant challenges in designing suitable projects. In...6). Methionine synthesis in S. cerevisiae (Figure 1) occurs through a well-characterized pathway with ...sequences for ten different MET/Met genes (Figure 1) from the two yeast species into the pYES2.1/V5-His...selected from different parts of the Met pathway (Fig. 1). In addition to the complementation experiments that...about Clare at the Biology Dept. site.  References 1. American Association for the Advancement of Science...Over Time project The Pathways over Time project provides a framework for these undergraduate research questions...
  28. Simplify Cloning with in vivo Assembly

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    ...very helpful to confirm primer design.  Use minimal template DNA Use 1 ng of PCR template DNA to minimize...two-step, 2 hr protocol prior to transformation (Figure 1). As this approach requires no special reagents or...with linearized vector backbone. DpnI digestion - 1 μl DpnI is added to the PCR mix to remove parental... by PCR, so we usually add DMSO (3%) and Betaine (1 M) to the PCR mix. When PCR is not possible Some plasmids...Twitter @jakefwatson and @JGarciaNafria.  References 1. Jones, Douglas H., and Bruce H. Howard. "A rapid ...ultracompetent (109 CFU/μg) cells. Primer design Using specific primer design (Figure 2), IVA cloning can be used...primers that bind at either side of the undesired portion, designed to amplify the rest of the vector sequence...
  29. Using Phosphoserine to Study Protein Phosphorylation

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    ...cellular proteins are modified through phosphorylation (1). However, the expansion of studies on protein phosphorylation...three components required for translation (Figure 1): A tRNA that recognizes a specific ‘open’ codon ... open reading frame (ORF) of interest (Figure 2). 1. The phosphoserine OTS The backbone of the phosphoserine...modification allowed the deletion of release factor 1, the protein responsible for terminating translation...Rinehart lab: pCRT7 NT TOPO E17TAG GFP and pGEX-6P-1. The pCRT7 NT TOPO vector contains a mutant pSer-containing... can follow her on Twitter @nieminm.   References 1. Cohen, Philip. "The origins of protein phosphorylation...site-specific incorporation of phosphoserine (as described below) provides researchers with a valuable tool for understanding...
  30. CRISPR 101: Making a Knock-In Cell Line

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    ... arms. Nat Chem Biol., 308(20): 1-9 (2020). 10.1038/s41589-019-0432-1 Mehdi Banan. Recent advances in ...limits of oligonucleotides. These donors traditionally have larger homology arms in the 500 bp to 1 kb range...before attempting knock-ins by HDR.   Fig. 1: Early steps in repair of a DNA double strand break...breaks. J Biol Chem., 293(27): 10524-10535 (2018). 1 10.1074/jbc.TM118.000372 Yang, H., Ren, S., Yu, S....harnessing the homology-directed repair pathway, designing the best donor DNA, and avoiding common mishaps...knock-in. Then choose which Cas enzyme to use and design a gRNA to where you would like to introduce the...sequence to introduce, which is done through the design and use of a donor DNA molecule. Your donor molecule...
  31. Starter guide to induced pluripotent stem cells (iPSCs) part 1:  A renaissance in regenerative medicine

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    ...kmukherjeephd/. References 1. Dittrich, R., M.W. Beckmann, and W. Wurfel, Non-embryo-destructive Extraction of Pluripotent...into more specialized cells with specific functions [1]. In many tissues, stem cells serve to replenish/replace...damaged cells that no longer function adequately [1]. Stem cells’ ability to differentiate into multiple...The potential of muscle stem cells. Dev Cell, 2001. 1(3): p. 333-42. PubMed PMID: 11702945. 6. Cowan, C....preimplantation genetic diagnosis. Hum Reprod, 2008. 23(1): p. 46-53. PubMed PMID: 17989069. 8. Takahashi, K...essence, pluripotent cells can be thought of as descendants of totipotent cells. An example of pluripotent... produced Ethical concern High. Embryos are destroyed during ESC isolation. Low Chances of post-transplantation...
  32. Cpf1: A New Tool for CRISPR Genome Editing

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    ...guide for a refresher on CRISPR/Cas9.  Figure 1: Cpf1 is a single RNA-guided endonuclease of a class... than the multi-subunit complex employed by class 1 systems. A putative new class 2 nuclease, Cpf1 (CRISPR...that Cpf1 can tolerate mismatches at gRNA positions 1, 8, 9, and 19-23. Accordingly, the 3’ end of the gRNA...Most gRNAs directed low-frequency Cpf1 cleavage at 1-12 off-target sites; in contrast, SpCas9 may cleave...the diversity of CRISPR-based systems. References 1. Zetsche, Bernd, et al. "Cpf1 is a single RNA-guided... crRNAs for Cpf1-mediated cleavage are 42-44 nucleotides in length, about the same size as Cas9’s, but...SpCas9. Since Cpf1 doesn’t require a tracrRNA, crRNA guides are only ~42 nt long. Direct synthesis of these...
  33. Some Like it Hot: Thermostable GeoCas9

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    ...Figure 1 for a summary of the experimental results. GeoCas9 RNP editing in mammalian cells Besides being...Cells? Yes Yes Longevity in Serum?* No Yes Table 1. Comparing SpCas9 and GeoCas9. *For in vitro Cas9 ...GeoCas9 is active at high temperatures Figure 1: Thermostability of SpCas9 vs GeoCas9. SpCas9 or GeoCas9...from 25-80 °C. Activity is expressed as Kcleave (min-1). SpCas9 has maximum activity from 35-45 °C, while...
  34. CRISPR 101: Targeting RNA with Cas13a (C2c2)

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    ...  Figure 1: Using Cas13a as a diagnostic tool. A pool of DNA or RNA nucleotides containing a sequence...C2c1, C2c2 and C2c3 (short for Class 2, candidate 1, 2, or 3). C2c1 and C2c3 are related to Cpf1, but ...lacks the ability to cleave the RNA target.  Table 1: Comparison on Common CRISPR Enzymes Name  Enzymatic... This system, dubbed SHERLOCK (depicted in figure 1) has been used to differentiate strains of Zika virus...contributed to the update of this post. References 1. Abudayyeh, Omar O., et al. "C2c2 is a single-component...Reverse-transcription RPA (RT-RPA), respectively. Amplified nucleotides are combined with Cas 13a in complex with crRNA...the target sequence is present in the pool of nucleotides, the nonspecific RNAse activity of Cas13a becomes...
  35. Design Tips for Prime Editing

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    ...transcriptase (RT) template including the desired edit. Figure 1: Prime Editing schematic. Created with...great tips to guide your experimental design, especially the design of the RNA sequences you’ll use in prime...principles pegRNA design If you’re just starting out with prime editing, you’ll need to design and optimize... be edited and the sequence of the edit, so its design changes for every new prime editing application...transcriptase template, starting with about 10–16 nucleotides. For longer templates, it is even more important...and PE5b: In this approach, the nicking sgRNA is designed to bind only after the edit is installed. This...approach. Figure 7: Nicking sgRNAs can be designed to target edited DNA, so that nicking only occurs...
  36. Deciphering the Mysteries of Behavior with Viral Vectors

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    ...production of the pro-inflammatory cytokine interleukin IL-1 beta in the dorsal raphe nucleus (DRN), a region thought... a transgenic mouse harbouring a Cre-dependent IL-1 beta overexpression cassette. Expression of Cre in...in these neurons turns on overexpression of IL-1 beta. They tested the mice in a series of behavioral ...risky), or a closed arm (safe). Mice with higher IL-1 beta production spent more time in the open arm and... part of the apparatus, it turned out that the IL-1 beta overexpressing mice spent more time in the risky...Over the past decades, neuroscientists have made great strides to map brain regions and allocate specific...for this task. However, most lesioning methods destroy areas larger than intended and may unintentionally...
  37. Viral Vectors 101: Virus Safety

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    ...including yourself as the researcher.   Figure 1: Separation of retroviral packaging components onto...these reasons, AAV is usually classified as a BSL-1 safety level. Adenovirus is similar to AAV in that...lab coats are either recommended or required in BSL-1 and required in BSL-2 labs. When working with lentivirus...required whenever there’s a splash or spray risk in BSL-1. In BSL-2 labs, eye protection is required any time...isopropyl alcohol, 0.5% peracetic acid, 10% bleach, or 1% iodine are useful. Some organizations or cities may...that are built into how something functions, were designed for this purpose. One such control is dividing...
  38. Easi-CRISPR: Generating Knock-In and Conditional Mouse Models

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    ... Figure 1: In conventional gene targeting (A), you must first generate your desired mutation in mouse...much more favorable than previous methods yielding 1-10% knock-in. Read on to learn how you can make CRISPR... drug induction systems (ttA or rtTA) are between 1 to 2 kb in length. There are plenty of Addgene plasmid...CRISPR ribonucleoproteins.” Genome Biol. 18 (2017) (1):92. DOI: 10.1186/s13059-017-1220-4 PubMed PMID: 28511701... using long ssDNA donors.” Nat Protoc. 13 (2018) (1):195-215. DOI: 10.1038/nprot.2017.153 PubMed PMID:...engineering using CRISPR nucleases. Genome Biol. 19 (2018) (1):25. DOI: 10.1186/s13059-018-1400-x PubMed PMID: 29482575...using in mouse transgenics. Designing an Easi-CRISPR knock-in allele To design a knock-in allele at a given...
  39. Deep Dive: Fixing and Permeabilizing for Immunofluorescence

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    ...Fig. 1). So, while organic solvents may improve antibody binding for some targets, they can destroy it ...preventing your primary antibody from binding (Fig.1). The level of cross-linking that occurs depends on...thing depending on your experiment.   Figure 1: Choice of fixation method impacts antibody binding...New York, pp 299–311. https://doi.org/10.1007/978-1-4939-8935-5_26  Rolls G (2022) Process of Tissue Fixation...www.leicabiosystems.com/us/knowledge-pathway/fixation-and-fixatives-1-the-process-of-fixation-and-the-nature-of-fixatives...critical to the outcome of your IF experiment and deserve careful thought and attention.   * There are other...
  40. 500,000 Plasmids Shipped and Counting!

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    ...here at Addgene – 500,000 plasmids shipped! That's a 1/2 million plasmids sent to happy scientists around...start out at our Cambridge office – previously at 1 Kendall Square, but newly relocated to 75 Sidney Street...Have a question? Email: [email protected] Call: +1 (617) 225-9000         ...information in our lab software, labeling stabs with barcodes as they go. Stabs are organized by shipment and...
  41. Plasmids 101: Secondary Nanobody Toolbox

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    ...incubation of 1° and 2° Must use different species and/or different IgG subclasses of 1° for multi-color...displacement 2° incubation can be skipped by pre-binding to 1° Monovalent Monoclonal Only anti- rabbit and -...dyes are also commercially available. References 1. Pleiner, T., Bates, M., & Görlich, D. (2017). A toolbox...NIH’s Developmental Studies Hybridoma Bank (DSHB). 1 ml of antibody-containing hybridoma supernatant is...their production requires animal sacrifice and precludes genetic engineering of a tag or fusion with a ... with secondary nanobodies conjugated with the desired fluorophores. In figure 4B below, triple colocalization...review. If you just want to use the nanobodies described in Pleiner et al, the key steps for generating...
  42. Clear and Accessible Writing

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    ...writing Let’s use Figure 1 as our example. Remember, our goal is to use words to describe the image in a way...information as sighted readers.    Figure 1: An image from AAV Purification by Iodixanol Gradient...are they hoping to get from it? The image in Figure 1 appears on our protocol page for AAV Purification ... share with the rest of the workshop.  For Figure 1, Addgene chose this alt text: "The left panel is a... to our website through the use of alt text to describe images in online spaces. Alt text is used by screen... your alt text, use all of this information to describe the image helpfully. You and your readers are ...learned a lot from listening to others' alt text descriptions, and we’d love to hear yours as well.  More ...
  43. Quick Guide to Working with Drosophila Part 2: Controlling Gene Expression in Flies with Gal4/UAS

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    ...transcription activation system co-opted from yeast (1). It is a Drosophila geneticist’s main workhorse to...he still reads “#” as a “pound symbol”. References 1. A. H. Brand, N. Perrimon, Targeted gene expression... A Fly Geneticist’s Swiss Army Knife, Genesis 34, 1–15 (2002).PubMed PMID: 12324939. 3. S. E. McGuire,...Versatile Toolkit for Gene Expression in Drosophila, 3, 1–10 (2015). PubMed PMID: 21356876. 5. J. Chow, Z. Marka...references and web links from my first post and start designing your first fly experiment! Many thanks to our...PMID: 28704652. 6. V. Rodríguez, D. Didiano, C. Desplan, Power tools for gene expression and clonal analysis...
  44. Plasmids 101: Mammalian Vectors

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    ...premature chain termination 1-10 ug/mL Zeocin Sh bla HeLa, NIH3T3, CHO, COS-1, 293HEK, Jurkat T cells Complexes...expressing the Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA1) or the SV40 large-T antigen (293E or 293T ...Concentation*** Blasticidin bsd  HeLa, NIH3T3, CHO, COS-1, 293HEK Inhibits termination step of translation ...mammalian plasmid components, it may be useful to describe the means of introducing genetic material (such...the plasmid in the same way. Selection methods, described below, are typically employed when creating stable...
  45. Treating Muscular Dystrophy with CRISPR Gene Editing

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    ... Figure 1: Exon skipping strategies for Duchenne muscular dystrophy. gRNAs can be designed to flank ...X-linked recessive disorder affecting approximately 1 in 5000 males. DMD is caused primarily by frameshift...needed. First, CRISPR delivery must be optimized to: 1. Reach a high percentage of muscle cells throughout...also be closer than we might expect.   References 1. Kaiser J. CRISPR helps heal mice with muscular dystrophy...diseases. Nucleic Acid Ther. 2014 Feb;24(1):69-86. PubMed PMID: 24506781. PubMed Central PMCID: PMC3922311...);186-91. doi: 10.1038/nature14299. Epub 2015 Apr 1. PubMed PMID: 25830891. PubMed Central PMCID: PMC4393360...dystrophin transcript. Unfortunately, the oligonucleotides only modestly improve muscle function, and they must...
  46. Early Career Researcher Toolbox: Social Media for Scientists

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    ...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 ...’s social media toolbox. Besides advice for using Twitter, this post provides suggestions for using LinkedIn...use Twitter as a scientist. While this post is designed with beginners in mind, there’s some great reminders...sheet from Science Media Savvy This tip sheet provides advice for tweeting and blogging as a scientist...
  47. CRISPR 101: Cytosine Transversion Editors

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    ...for more details on how they work!) Figure 1: Base transitions are edits between the purine bases...R-loop structure. In order to bind DNA, Cas9 requires (1) a guide RNA, (2) a complementary DNA sequence, and...given the pithier name CGBE1, for “C → G Base Editor 1,” and had a C → G editing efficiency of up to 68%... the CGBE: DNA polymerase D2 (POLD2), exonuclease 1 (EXO1), and RNA binding motif protein X-linked (RBMX...excision repair proteins. Nature Communications, 12(1), 1384. https://doi.org/10.1038/s41467-021-21559-9...transversions in human cells. Nature Biotechnology, 39(1), 41–46. https://doi.org/10.1038/s41587-020-0609-x...machine learning methods. Nature Communications, 12(1), 4902. https://doi.org/10.1038/s41467-021-25217-y...
  48. Antibodies 101: Choosing the Right Isotype

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    ..., rather than a broadly  reactive secondary (Fig. 1). For example, an anti-mouse IgG2a secondary would...IgG2a>IgG2b>IgG1 (Manning 2012).      Figure 1: Broadly reactive versus subclass-specific antibodies...antibody binding and therefore the signal strength (Fig. 1). Monoclonal primaries If you do decide on a monoclonal...raised in a different species.      Table 1: Isotype considerations when choosing antibodies ...Elsevier. https://doi.org/10.1016/s0091-679x(08)60255-1  Manning, C. F., Bundros, A. M., & Trimmer, J. S. ... and to work in a variety of applications. The desired specificity of your secondary antibody depends ...
  49. 3 Tips to Improve HDR Efficiency for CRISPR Editing in Human Cells

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    ...recently that desired genome-editing events by HDR can be generated more efficiently by (1) improving editing...specifically incorporate homo- or heterozygous mutations. 1. Increasing HDR accuracy with CRISPR/Cas-blocking ...targeted alleles when gene editing.   Figure 1: Techniques to improve editing efficiency.   But...provided by blocking mutations. Essentially, you:  Step 1 - Introduce the blocking mutation together with the...developing novel iPSC-based model systems.     References 1. Cong, Le, et al. "Multiplex genome engineering using...genome editing with CRISPR/Cas9 in human cells was described in 2013 (Cong et al, Mai et al) we were very excited...introduced. Although we were able to introduce the desired mutations in genes associated with dementia, such...
  50. No Llamas Required - Synthetic Nanobodies Against Membrane Proteins

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    ...crevices proteins on the cell surface. Figure 1: Comparison of common antibody, HCab, and nanobody...Humana Press, pp 133–148. https://doi.org/10.1007/978-1-62703-293-3_10 Walter J et al. (2020) Synthetic nanobodies...https://doi.org/10.1101/2020.04.16.045419.  Wrapp D, De Vlieger D, Corbett KS, Torres GM, Wang N, Van Breedam...Zimmermann et al., 2020). This selection platform was designed so that any standard lab can quickly select for...strongly to your target protein. The Seeger lab designed 3 different mRNA sybody libraries for use in the... randomized with a defined set of different trinucleotides (corresponding to different amino acids) in...for binding to the target protein. The protocol describes going through two rounds of phage display to increase...
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