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  1. 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...
  2. Lentiviral Vector Uses and Overview

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    Blog Post
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    May 19, 2016, 2:30 p.m.
    ...HIV-1 were transduced with a lentiviral vector containing an antisense sequence against the HIV-1 envelope...infect. Finally, the transfer plasmid encoded the desired transgene flanked by HIV-1 long terminal repeats...packaging, envelope, and transfer plasmids. The packaging plasmid carried a mutated HIV-1 provirus that couldn...section below! References 1. In vivo gene delivery and stable transduction of nondividing cells by a ...Trono and collaborators turned to the lentivirus HIV-1, well-known to infect non-dividing cells. The first... 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...
  3. Degrading DNA with Cascade-Cas3

    Type
    Blog Post
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    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 ...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 ...making up type I, the most abundant type in the Class 1 category. These type Is can then be further broken...editing in human cells. Nature Communications, 10(1). https://doi.org/10.1038/s41467-019-13226-x Cameron...non-target strand. The helicase domain is then activated, and Cas3 begins unraveling the double-stranded DNA ...
  4. When is a Monomer not a Monomer? The Top Three Ways Your Favorite Fluorescent Protein Oligomerizes in Cells

    Type
    Blog Post
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    April 19, 2016, 2:30 p.m.
    ...Figure 1).   Figure 1: Each problem with dimerizing fluorescent proteins is illustrated. 1) Membrane... dimerization.   1. Transmembrane fluorescent protein fusions Transmembrane proteins, i.e. receptors... in nature are prone to dimerization (i.e. EGFP) [1, 2] or even form obligate tetramers (i.e. DsRed) [...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...contacts that bring apposing membranes together and can wrap the membranes into stacked structures including...
  5. Antibody Validation for Flow Cytometry

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    Blog Post
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    Sept. 10, 2024, 1:15 p.m.
    ...their HLDA workshops. Let’s use TIM-1 (Single pass type-1 membrane protein), which has been designated...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...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...cells were stained with the indicated Synaptotagmin-1 antibodies and corresponding Multi-rAb CoraLite® Plus...between the wild-type and the KO population (Figure 1), further optimization can be performed to both maximize...
  6. 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...ve learned in Part 1, there are many types of genetically engineered mice: transgenic mice, knockin and...In Part 1 of our mouse modeling blog series, we covered techniques that can be used to introduce genetic..., and assuming Mendalian patterns of inheritance: 1. Genotype your parental mice In order to ensure that...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... integration of a novel gene randomly into their genome, some transgenic strains are difficult to breed...
  7. The Breast Cancer Microenvironment: A Tumor’s Backstage Team

    Type
    Blog Post
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    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 ... expression of TAK 1, an enzyme that controls apoptosis and regulates transcription. Without TKA1, cells...Agnieszka K., et al. "An absence of stromal caveolin-1 expression predicts early tumor recurrence and poor...microenvironment. This results in increased expression of transforming growth factor-β signaling, possibly inducing...let’s take a look at exosomes. Proficient in transportation, exosomes are tools of communication and provide... (micro RNA) and other molecules that can be transferred to other cells, inducing epigenetic changes in...
  8. 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., ...
  9. CRISPR-mediated Plant Base Editors

    Type
    Blog Post
    Published
    Jan. 3, 2019, 1:35 p.m.
    ...of the desired T-A base pair. Figure 1: Transition mutation (C>T, G>A, A>G, and T>C) installation...hAPOBEC3 deaminase can edit in a stretched window ranging from 1-17 bp relative to the PAM sequence (Zong et...excision repair mediated by uracil glycosylase (Figure 1). The presence of a uracil glycosylase inhibitor (... A-T base pair is converted to a G-C pair (Figure 1). As the cellular inosine excision repair is not as...Target-AID based (CBE-2)-  and rAPOBEC based (CBE-1)-  CBEs are successful base editors in rice, tomato...which recognize PAM sequences other than NGG (Table-1). Type Nickase Cas9 (D10A) Deaminase PAM requirements...locus/loci, choose a base editor variant from Table 1 depending on the PAM sequence. Avoid targeting a ‘...
  10. New Neuroscience Tool: The iGluSnFR3 Glutamate Sensor

    Type
    Blog Post
    Published
    April 7, 2022, 1:15 p.m.
    ...sensing glutamate using both 1-photon and 2-photon imaging.   Figure 1: 1P and 2P excitation and ...hSynap: Human Synapsin-1 promoter. Good for neuronal expression. hSynap-FLEX: Synapsin-1 promoter, FLEXed for... v857. Image adapted from Aggarwal et al., Figure 1   Increased versatility through two different...expression in Cre-expressing cells. hSynap-FLP: Synapsin-1 promoter, FLP-dependent expression GFAP: Glial fibrillary...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 ...
  11. A Needle in a Base-Stack: Cas9 Structural Biology

    Type
    Blog Post
    Published
    June 4, 2024, 1:15 p.m.
    ...nucleotides 1-10 of the guide RNA, prearranged for base pairing with a complementary DNA strand. These 10...4CMP) with domains colored as in Figure 1. HNH, red; RuvC, orange; CTD, yellow; REC lobe, light blue; bridge...10.1146/annurev-biophys-062215-010822 Nishimasu, H., Ran, F. A., Hsu, P. D., Konermann, S., Shehata, S. I.... basic parts of the Cas9 enzyme.   Figure 1: A cartoon depiction of Cas9’s two major lobes, REC...the CRISPR system (Nishimasu et al., 2014). Table 1. Summary of Cas9 domains, the lobe each domain belongs... on itself at the bottom of the image. Stem loops 1 and 2 extend horizontally across both lobes. The guide...outside of the protein, spanning both lobes. Stem loop 1, nestled between the REC and CTD domains, is required...
  12. Four Ways to Package Transgenes That Exceed the Size Limit of Adeno-associated Virus

    Type
    Blog Post
    Published
    Sept. 1, 2020, 1:15 p.m.
    ...and drawbacks of four split AAV vector approaches. 1. Overlapping  Overview: The overlapping strategy has...Adeno-Associated Virus Capsids. Human Gene Therapy Methods 27:1–12 . https://doi.org/10.1089/hgtb.2015.140 Frischmeyer... successfully mediated transduction and expression of the full-length transgene in vitro and in vivo (...this, larger functional transgene products were produced following transduction.  So what’s going on here...between part A and B of the transgene to reconstitute the full-length transgene (Chamberlain et al., 2016...cells in mice. This vector transduced ~10% of cells, similar to the transduction rate of a single AAV. Odom...muscle physiological performance.  2. Trans-splicing Overview: For trans-plicing, splice site donor and acceptor...
  13. CRISPR-based Genome Editing Systems For Editing in E. coli

    Type
    Blog Post
    Published
    April 13, 2021, 1:15 p.m.
    ... Then plasmids are cured from the cell. Steps 1-1 and 1-2 can be done simultaneously. Image from Li et...coli K-12 strains, 2 E. coli B strains, 1 E. coli W strain, and 1 Tatumella citrea, with a total of 70 sites...the pCas/pTargetF system.   Figure 1: The editing process begins with the addition of the sgRNA sequence...updates involved the following changes. In pCas9, we 1) replaced the promoter of gRNA-pMB1 with PrhaB, 2)...biosynthesis, we constructed a strain library with 1-11 copies of integrated genes. We obtained a stable...in E. coli BL21(DE3) as transformants failed to grow after the transformation of pTargetF into the BL21...pTnsABC expresses the transposases TnsA, TnsB, and TnsC pQCascade expresses the transposase TniQ, the Cas proteins...
  14. Hot Plasmids February 2024

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    Blog Post
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    Feb. 20, 2024, 2:45 p.m.
    ...Biotechnology, 10.1038/s41587-023-01756-1. https://doi.org/10.1038/s41587-023-01756-1. PMID: 37095348. Breaking... for molecular fusion and membrane-targeting applications. Nature Methods, 1–9. https://doi.org/10.1038...incubation, even with multiplexed guides. Figure 1: A) Cell-penetrating Cas9, fused to HIV TAT, Myc and...expressing COX8a-mStayGold. Scale bars 10 μm (main), 1 μm (inset). Image reused from Ando et al. 2023, under...StayGold fluorescent protein. Nature Biotechnology, 1–4. https://doi.org/10.1038/s41587-023-02018-w. PMID...broad tropism in primates. Nature Communications, 14(1), 3345. https://doi.org/10.1038/s41467-023-38582-7...StayGold variants AAV.CAP-Mac for systemic gene transfer in primate brains Endothelial-specific AAV delivery...
  15. Technique: Probe Phage Genomes for Host Binding Proteins

    Type
    Blog Post
    Published
    Sept. 29, 2016, 2:30 p.m.
    ...successfully identified using this method. Step 1: Prepare a random fragment library of phage DNA This first ...and leave for 1 h at room temperature. After this, it is helpful to subject your membrane to several freeze... the membrane itself or to any “sticky” proteins expressed by your library. After blocking for 1 h at ...it can really help to incubate the membranes overnight in 500 mM to 1 M NaCl in order to enhance folding...place to start) and add your membranes to the solution, shaking gently for 1 h at room temperature. This... on Twitter @JessicaSacher.   References 1. Nobrega, Franklin L., et al. "Revisiting phage therapy: new...which is also gaining a lot of new traction lately (1, 2), depends on knowledge of the structure(s) a given...
  16. History of CRISPR Cas - A tale of survival and evolution

    Type
    Blog Post
    Published
    Nov. 25, 2013, 10:12 p.m.
    ...Davidson AR.  Nature. 2013 Jan; 493, 429–432. Cong L, Ran FA, Cox D, Lin S, Barretto R, Habib N, Hsu PD, Wu...sequences were initially discovered in E. coli in 1987 (1), the concept that these clustered repeat sequences...neutralize CRISPR/Cas. Earlier this year, expression of 1 of 5 anti-CRISPR genes were found to inactivate the...and are not translatable to the other CRISPR subtypes. Still, the large and dynamic range of CRISPR systems...well-suited for various innovative biological and translative technologies. Addgene has empowered researchers...http://en.wikipedia.org/wiki/File:Crispr.png Barrangou R, Horvath P. Science. 315, 2007 Jan; 1709–1712...CRISPRdb. Date: 2013-09-18. Makarova K, Haft DH, Barrangou R, Brouns SJJ, Charpentier E, Horvath P, Moineu...
  17. FastCloning: A Newer, Simpler Cloning Technique

    Type
    Blog Post
    Published
    Nov. 1, 2016, 2:30 p.m.
    ... PCR leads to the most colonies after transformation. When a 1:1 vector:insert ratio is used in the DpnI... get tips for applying it in your own lab. Table 1: Comparison Between Standard Restriction Cloning and...Connecticut interested in protein science.     References: 1. Celie, Patrick HN, Annabel HA Parret, and Anastassis...PCR cloning method." BMC biotechnology 11.1 (2011): 1. PubMed PMID: 21992524. PubMed Central PMCID: PMC3207894...products are then transformed directly into chemically competent E. coli and transformants selected with ... for further purification before transformation. After transforming cells, you should perform colony ...consisting of digestion, purification, ligation, and transformation. While restriction cloning is still routinely...
  18. Antibodies 101: Designing Your First Flow Panel

    Type
    Blog Post
    Published
    May 28, 2024, 1:45 p.m.
    ...marker. Looking at Table 1, we can recognize a couple of fluorophores from Figure 1. For example, the chart...called Fluorescence Resonance Energy Transfer (FRET).   Figure 1: Emission spectra and respective ...efficient (i.e., happen most of the time). Figure 1 shows a graph from the BD® Spectrum Viewer, outlining... the brightness of individual fluorophores. Table 1 describes the brightness of a few commonly used fluorophores...Brighter fluorophores have a stronger signal. Table 1: Degrees of brightness for a few commonly used fluorophores...blue laser excites at a wavelength of 488 nm (Table 1), which is near a local maximum of PE's excitation...Knowing that the red laser excites at 640 nm (Table 1), while comparing the two fluorophore's excitation...
  19. Addgene Depositors Get More Citations

    Type
    Blog Post
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    April 20, 2017, 2:30 p.m.
    ...of publication. Table 1 provides an example calculation of the weights. Table 1: Journal Weighting Example...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...on a range of topics including biotech and research tools, computing performance, and randomized control...
  20. Cancer, Inflammation and Immunity - Harnessing the Body’s Defenses to Fight Cancer

    Type
    Blog Post
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    July 6, 2017, 1:59 p.m.
    ...aggregation, and potentiates the effect of PD-1 blockade.“ (Ref 4). PD-1 helps tumor cells evade the immune system...fasting has a positive effect on cancer treatment (Ref 1). As described in the presentation, starvation or ...of the immunosuppressive cell surface receptor PD-1. This immunosuppressive environment in turn may represent...  (Chimeric Antigen Receptors) CAR T cells and PD-1 modulators. An exciting development in immunotherapy...free deposit and distribution service! References: 1. Pietrocola, Federico, et al. "Caloric restriction...discussed and Professor Caetano Reis e Sousa from the Francis Crick Institute concluded “Aspirin promotes autophagy... Kettering Cancer Center. In contrast to using randomly integrating viral vectors, CRISPR/Cas9 genome ...
  21. An Integrin Antibody Toolkit from IPI

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    Blog Post
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    March 28, 2024, 1:15 p.m.
    ...-Integrin alpha 5 beta 1 [IPI-ITGA5/ITGB1.2] Integrin alpha-5,Integrin beta-1 Human, Mouse IgG1 Rabbit...-Integrin alpha 5 beta 1 [IPI-ITGA5/ITGB1.4] Integrin alpha-5,Integrin beta-1 Human, Mouse IgG1 Rabbit...specific integrins in cellular processes.   Figure 1: Integrins can shape into three conformations: (A)...immunoprecipitation and immunohistochemistry. Table 1: IPI antibodies  Antibody Target Proteins Reactivity...Human IgG1 Rabbit Anti-Integrin alpha M [IPI-LM2/1] Integrin alpha-M Human IgG1 Rabbit Anti-Integrin...Human IgG2a Mouse Anti-Integrin alpha M [IPI-LM2/1] Integrin alpha-M Human IgG2a Mouse Anti-Integrin... β1 integrin mechanics. Nature Communications, 13(1), 7471. https://doi.org/10.1038/s41467-022-35173-w...
  22. Plasmids 101: TOPO Cloning

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    Blog Post
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    Oct. 27, 2016, 2:30 p.m.
    ...between the cleaved 3′ DNA strand and a tyrosyl residue of topoisomerase I (1). If a 5′ hydroxyl group ...plating your transformation may allow you to see colonies within 8 hours. References: 1. Shuman S. "...Let’s break down the steps needed for TOPO cloning: 1. Create Your PCR Product: Design standard primers ...mind that Taq polymerase has an error rate of about 1 in 3,500 bases. Typically polymerases with proofreading...enzyme and Taq, with Taq used in an excess ratio of 10:1. Gel purify your PCR product and incubate it with ...different DNA strand comes along, it can attack this covalent bond thus joining the two DNA strands and releasing...planning to transform right away OR you can store the reaction at -20C overnight. 4. Transform TOPO Cloning...
  23. 5 Uncommon Ways to Gain Career Skills During an Uncommon Time

    Type
    Blog Post
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    Oct. 20, 2020, 1:15 p.m.
    ...need a job. Start now. Informational interviews are 1:1 discussions with someone who has interesting experiences...conversation builds a relationship for the future and the 1:1 format is good for everyone including those that ...out-of-the-box ideas that might jump start your learning. 1. Create a peer mentoring group We don’t all get the... and not in academia is run by grant funding. Learning to write grants quickly, efficiently and effectively...apply to or offer to help with lab grant writing. You may not get the grant or your PI may edit everything...thinking about future career options. 5. Write a grant - even if you don’t need one A lot of science in...valuable skill. There are many different kinds of grants that you can apply for. If you are in a lab, your...
  24. Supporting Rare Disease Research with BeHeard 2017

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    Blog Post
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    July 20, 2017, 2:30 p.m.
    ...estimated to affect anywhere from 1 in 6,000 to 1 in 19,000 live births (1).  While disruption of the smn1... funding opportunities. References 1. Jones, C., et al. "PP09. 1–2352: Systematic review of incidence...disease. This year, Addgene will be providing plasmid grants worth $2,000 each to two labs through the BeHEARD...
  25. Quickest Way to Deposit Plasmids: The Deposit Spreadsheet

    Type
    Blog Post
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    March 8, 2017, 3:15 p.m.
    ...spreadsheet to complete Step 1. Steps 2 and 3 are usually very easy — our tech transfer team will communicate...scientist, you will have the most involvement with Step 1, and, while data entry can be a chore, we’ve made ...Deposit” and “Download Deposit Spreadsheet” (see Figure 1). Please read our “How to Deposit Your Plasmids with...thorough guide to our online data entry process. Figure 1: Begin the deposit process by clicking “Submit Online...spreadsheet (Figure 2) and are described in Table 1. Some cells have drop-down options for you to choose...and are exceptions to our standard workflow.  Table 1: Guidelines for the data fields in the deposit spreadsheet... Send plasmid information to Addgene Material Transfer Agreement (MTA) approval  Send plasmids to Addgene...
  26. A Primer on Optogenetics: Introduction and Opsin Delivery

    Type
    Blog Post
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    Sept. 10, 2015, 2:30 p.m.
    ...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...
  27. AAV Titers: Where Do They Come From And What Do They Mean?

    Type
    Blog Post
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    Nov. 15, 2017, 3 p.m.
    ...near-perfect physical-to-infectious particle ratio of 1:1 (Zeltner et al., 2010). However, for recombinant ...preparations are genome-containing (Figure 1).    Figure 1: Electron micrograph of an Addgene AAV...reported a physical-to-infectious particle ratio of 50:1 (Zeltner et al., 2010). The specific infectivity of... lot (if we still have it available). References 1. Fagone, Paolo, et al. "Systemic errors in quantitative... Human Gene Therapy, Part B: Methods 23.1 (2011): 1-7. PubMed PMID: 22428975. PubMed Central PMCID: PMC3640491...particles that can transduce cells. Infectious titers are typically quantified by cell transduction assays. Wild-type....qPCR...Digital droplet PCR...DNA dot blot...Transduction assay...SDS-PAGE...Electron microscopy… Any ...
  28. REPLACR Mutagenesis: Replacing In Vitro Recombination Methods

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    Blog Post
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    Feb. 10, 2016, 3:30 p.m.
    ...deletions, point mutations PCR Reactions 1 1 1 per fragment 1 per fragment In vitro Assembly No No Yes...methods for site directed mutagenesis   References 1. Trehan, Ashutosh, et al. (2016). “REPLACR-mutagenesis... and the nonmethylated PCR products are then transformed into E. coli to undergo nick repair. This method...containing the desired mutations, to amplify both strands of a plasmid template. In addition to containing...template plasmid, these PCR products are directly transformed into bacteria expressing recombineering proteins...fine, especially using plasmids in the 10-12 kb range. REPLACR-mutagenesis also requires making your own...
  29. Viral Vectors 101: Transductions

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    Blog Post
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    April 30, 2024, 1:15 p.m.
    ...type, and/or desired event.   Figure 1: Transduction to expression process. A viral particle enters...triple T’s of biology are transformations, transfections, and transductions! In this blog we will discuss...intricacies of transductions, we've got you covered there too. What is a transductionTransduction is the ... experiment. Using transduction vs. another method Transfection and transduction seem to achieve similar...picky when it comes to transfection/transduction methods. Some ‘difficult to transfect’ cells lines are amenable... process of transferring foreign nucleic acid into a cell by a viral agent. Transductions are similar ...to find out more! Molecular basis of transduction Transductions utilize the ‘normal’ mechanism of viral...
  30. Plasmids 101: Control Plasmids

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    Blog Post
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    April 9, 2015, 3:29 p.m.
    ...Gene X using shRNA expressed from a plasmid   Figure 1: Expression Level of Gene X The results shown above...Referring back to the experiment associated with Figure 1, the independent variable is the shRNA. Therefore ...the protein.   In analysis of the result in Figure 1, an internal control, such as the GFP-expressing Plasmid...control and is consistent with the result in Figure 1 could look like this: Figure 2: Expression of Plasmid...plasmid.  Let us now revisit our experiment. In Figure 1, it appeared as though the shRNA did not knock down...scientific inquiry and investigation. References: 1. The problem of pseudoreplication in neuroscientific...effects of the transfection itself (i.e., the vector used in transfection, transfection reagent, or transfection...
  31. Quick Guide to All Things Lentivirus

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    Blog Post
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    March 21, 2017, 2:30 p.m.
    ...family including human immunodeficiency virus type-1 (HIV-1), can infect both dividing and non-dividing cells...promoter, and the desired gene (transfer vector plasmid), 2) the HIV-1 genome containing all viral genes...have been devoted to develop efficient and safe HIV-1-derived lentiviral vectors due to their ability to...lentiviral vectors consisted of three plasmids encoding 1) the lentiviral vector genome which was composed of...generation because this vector requires only three HIV-1 genes (gag, pol, and rev) for production. Third generation...several protocols that have been described (protocol 1, protocol 2, protocol 3) to find the one that will...to additional protocols and plasmids.  References 1. Miller, A. DUSTY, and C. A. R. O. L. Buttimore. "...
  32. Hot Plasmids June 2018 - Reverse transcriptase, nanobody, and protein-DNA interaction tools

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    Blog Post
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    June 27, 2018, 1:16 p.m.
    ...approximately 20 nm of a specific DNA sequence in only 1 min. Using these lentiviral plasmids, catalytically...expressing a novel reverse transcriptase (RT), MarathonRT. Reverse transcriptases are critical tools for ... to transform and express in bacteria, which, in turn, makes them more adaptable to a broad range of applications...!  MarathonRT: A highly processive reverse transcriptase Article contributed by Will Arnold  Listen ...RTs in this regard and is even able to reverse transcribe the extremely long, highly structured HCV genome...structured template!). MarathonRT also faithfully transcribes RNA to DNA with low error rates compared to other... are dependent on long, error-free, reverse transcription of RNA such as long-read cDNA sequencing and...
  33. Visualizing Translation at the Single Molecule Level

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    Blog Post
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    Aug. 1, 2017, 1:15 p.m.
    ... for studying translation in various cell types and physiological states. References 1. Ingolia, Nicholas...various stimuli on global translation, but a visual technique to study translation remained elusive. Two ...easier to track translation in two different ways: by monitoring the first round of translation or by tracking...destination co- or post-translationally. TRICK: Visualizing the first round of translation While ribosome profiling...in the fluorescent signal: untranslated RNAs appear yellow, and translated RNAs appear red. To enable ...Using translation inhibitors cycloheximide and puromycin, Halstead et al. verified that translation is necessary...readout of relative reporter translation. Single molecule continuous translation tracking TRICK allows you...
  34. Scientific Reproducibility - Focusing on Solutions at the Minisymposium on Reproducibility

    Type
    Blog Post
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    May 18, 2018, 7:32 p.m.
    ... handed out at the event). Program 0 - 1:24 - Intro 1:24 - 29:31 - Reproducibility Overview - Jeffrey... 49:45 0 1:18:45 - Reagent Development - Steven C. Almo, Institute for Protein Innovation  1:18:45 - 2...reproducibility As Jeffrey Flier points out in his talk (1:24 - 29:31), there are a variety of ways of defining...enterprise towards greater reproducibility. Cause 1: Inability to repeat previously performed experiments...the Institute for Protein Innovation (IPI) (49:45 - 1:18:45), there are also initiatives to create more ...found. Consider the hypothetical situation in Figure 1 where many scientists are performing similar experiments...using the actual tool that you ordered and not a random aliquot pulled from a freezer. As you’ll see in...
  35. Technical Design of a Western Blot

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    Blog Post
    Published
    Aug. 22, 2024, 1:15 p.m.
    ...Tris-tricine 2.5–40 kDa Tris-tricine 30 V, 1 hour or 100 V, 1–2 hours Good separation, quality, and stability...Limited protein size range Tris-acetate 40–500 kDa Tris-tricine 150 V, 1–3 hours Good for higher...detection quickly (~1 minute), and have a linear response over a broad dynamic range that typically spans...lot to cover, so let's dive in!      Figure 1: The technical decisions to make when designing a ...assay. The most common options are 4 °C overnight or 1–2 hours at room temperature (RT). Most people choose...overnight at 4 °C and their secondary antibody for 1–2 hrs at room temperature, which allows them to reduce...weight of the proteins you’re interested in. Table 1 lists the most common types of gels for SDS-PAGE running...
  36. Droplet Digital PCR for AAV Quantitation

    Type
    Blog Post
    Published
    Jan. 16, 2020, 2:18 p.m.
    ...the range of the assay for a wide range of titers. We usually dilute our samples 1:6 million to 1:25 million...important to note that the dynamic range of the ddPCR is between 1 and 100,000 genome copies (GC) per ...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...determine if your titers are within the expected range. We have also found that generating the standard...For these reasons, we are in the process of transitioning our titering method from qPCR to ddPCR. Droplet...
  37. Fluorescent Tagging of Endogenous Genes with SapTrap

    Type
    Blog Post
    Published
    Oct. 12, 2017, 2:26 p.m.
    ... 5’ and 3’ homology arm repair template (Fig. 1, Step 1). There is no need for PCR or cloning, as digestion...selectable marker, and connector to be released (Fig. 1, Step 2-3). Since donor plasmids of the same type ...correctly assembles the final targeting vector (Fig. 1, Step 4), and co-injection of the targeting vector...human cells. To use CRISPaint, users need 3 vectors:  1) a gRNA vector that targets the gene of interest, ... Tagging with Short Homology Donors.” Cell Rep.15(1) (2016):210-8. PubMed PMID: 27052166. Kunzelmann,...of the endonuclease Cas9 to create a DNA double stranded break (DSB) at a genomic site specified by a guide...tag. The two PCR reactions are then mixed and transfected along with a Cas9 expression vector. They can...
  38. Antibodies 101: Producing Recombinant Antibodies

    Type
    Blog Post
    Published
    Aug. 13, 2024, 1:15 p.m.
    ...materials have been washed away (Figure 1).      Figure 1: The steps of rAb production. Created ...Durocher Y. Transient Gene Expression in Suspension HEK293-EBNA1 Cells. Methods Mol Biol. 2018;1850:1-16. doi...Neuroscience Research. Curr Protoc Neurosci. 2020 Dec;94(1):e106. doi: 10.1002/cpns.106. PMID: 33151027; PMCID...doi: 10.1007/978-1-4939-8730-6_1. PMID: 30242676. Frenzel A, Hust M, Schirrmann T. Expression of recombinant...detection, and control. Int J Pharm. 2018 Oct 25;550(1-2):251-268. doi: 10.1016/j.ijpharm.2018.08.043. Epub...mammalian cells can perform human-like post-translational modifications that bacterial and most yeast ...be produced through a single or dual-plasmid transfection, depending on whether the heavy and light chain...
  39. Sleeping Beauty Awakens for Genome Engineering

    Type
    Blog Post
    Published
    June 30, 2015, 2 p.m.
    ...perform gene transfer in vertebrates. The system is comprised of 2 components: 1) an SB transposase, the enzyme...References 1. Kowarz E, et al. Optimized Sleeping Beauty transposons rapidly generate stable transgenic cell...important for social and regulatory reasons. 1.) The transposon consists of a mirrored set of inverted repeats...T cells to target CD19. Immunol Rev. 2014 Jan;257(1):181-90. doi: 10.1111/imr.12137. PubMed. Find the ...contains the transposase gene (red) for expressing the transposase enzyme.2.) The transposase enzyme is ...which cuts the DNA.3.) The released transposon can now bind a strand of DNA with a TA dinucleotide (there...removal of the transposon; the plasmid is then degraded by the cell.4.) The transposase creates a double...
  40. Multiplex Genome Editing with CRISPR-Cpf1

    Type
    Blog Post
    Published
    May 9, 2017, 2:12 p.m.
    ...For these experiments, cells were infected with a 1:1 ratio of two AAVs,  one expressing Cpf1 and the other...approaches have two main drawbacks: 1) Most rely on transfection of more than one vector to express the...comparison of Cpf1 vs. Cas9, see the table below. Table 1. Comparing the Cas9 and Cpf1 CRISPR Nucleases   ...leave them in the comments below.        References 1. Zetsche et al. "Multiplex Gene Editing by CRISPR–...the usual transfection drawbacks: transient expression and needing to work with a transfectable cell line...Cassettes transfection gRNAs expressed from a polycistronic transcript  Requires co-transfection of Cas9...Cassettes transfection gRNAs expressed from a polycistronic transcript Requires co-transfection of Cas9  ...
  41. Tips for Titering Your Lentiviral Preps

    Type
    Blog Post
    Published
    March 15, 2016, 2:30 p.m.
    ...critical first step of a successful transduction experiment. References 1. Kutner, Robert H., Xian-Yang Zhang... for predicting gene transfer events." Genetic vaccines and therapy 2.1 (2004): 1. PubMed PMID: 15291957...type of assay is a clonal cell line known to contain 1 integrated copy of the qPCR target gene. Developing...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...project forward, transductions should not be rushed into. Before you start any transduction, you should always...Primers targeting the transgene are also beneficial as they ensure that the correct transfer plasmid was used...
  42. Negative Can Be Positive: Open AAV Data with Addgene

    Type
    Blog Post
    Published
    Sept. 6, 2022, 1:15 p.m.
    ...across scientific disciplines. Scientific Data, 8(1), 1–11. https://doi.org/10.1038/s41597-021-00981-0 Wright...excellent at infecting our target neurons (Figure 1). However, this one set of experiments didn’t provide...yet none of that data was published.    Fig. 1: Testing of three different AAV serotypes (AAV1, 8...purification and formulation. Molecular Therapy, 12(1), 171–178. https://doi.org/10.1016/j.ymthe.2005.02.021...Stimulation. Frontiers in Human Neuroscience, 14(December), 1–12. https://doi.org/10.3389/fnhum.2020.578687 Additional...expressing neurons and GFP (green) to label neurons transduced by each serotype. Working at Addgene has ...answers hundreds of AAV questions every year on a range of issues related to AAV vectors, many from people...
  43. CRISPR Antimicrobials

    Type
    Blog Post
    Published
    May 3, 2016, 2:30 p.m.
    ..., they used 1-2 CRISPR crRNAs targeting sequences found only in certain bacteria (Figure 1). Citorik et...from 50% to 11% in just 24 hours.   Figure 1: Single-phage strategies for bacterial CRISPR targeting...genome, and it carries CRISPR machinery targeting 1) the given resistance gene and 2) a second lytic phage...the fight against bacterial superbugs. References 1. Citorik, Robert J., Mimee, Mark, and Timothy K. Lu...Targeted Bacterial Population Editing.” Cell Syst. 1(3):187-196. (2015). PubMed: PMID 26973885. Additional...antibiotic resistance using multiple approaches. Major restaurant chains including Chipotle and Panera Bread have... joining machinery, so a CRISPR-induced double-stranded break (DSB) in the genome is lethal. If this DSB...
  44. Plasmids 101: Gateway Cloning

    Type
    Blog Post
    Published
    Jan. 12, 2017, 3:30 p.m.
    ...References 1. Chee JY, Chin CF (2015) Gateway Cloning Technology: Advantages and Drawbacks. Clon Transgen 4:138...recombination sites (attL-left- and attR-right-, Figure 1). Under certain conditions, the attL and attR sites...regeneration of attP and attB sites.   Figure 1: Lambda phage integration and excision reactions. ...expression of the human KRAS gene in mammalian cells. STEP 1: Generate an Entry Clone There are a few different...could use a vector like pLenti CMV Puro DEST (w118-1) or the doxycycline-inducible pLIX_403. The chosen...the generation of the expression construct in only 1 day, as opposed to 2+ days with traditional restriction...sequencing or restriction digest! Then, you can transform or transfect the cells that you want to use for your...
  45. Getting to Know Expansion Microscopy

    Type
    Blog Post
    Published
    June 20, 2023, 1:15 p.m.
    ...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...jam packed with everything needed for synaptic transmission, are right around 250 nm, making it difficult...pre-expanded samples can sometimes take on a fragmented appearance post-expansion, but that doesn’t mean we should...brief history and new avenues. Philosophical Transactions Royal Soc 380:20210110. https://doi.org/10.1098...
  46. Viral Vectors 101: What is a Virus (and a Viral Vector)?

    Type
    Blog Post
    Published
    Aug. 18, 2023, 4:15 p.m.
    ... an envelope are called enveloped viruses (Figure 1). Like bacteria, only a tiny fraction of viruses are...are pathogenic (Balloux & van Dorp, 2017). Figure 1: A non-enveloped virus (left) and an enveloped virus...create far safer viral vectors that can be used in BSL-1 or BSL-2 labs. Viral vectors are viruses that have... https://doi.org/10.1016/B978-0-12-800947-5.00004-1 Taylor, M. W. (2014). What Is a Virus? In M. W. Taylor...reverse transcribe their gRNA into DNA, which is then transcribed into mRNA before being translated into ...genome types that can be either double stranded (ds) or single stranded (ss) (ie, dsDNA, ssDNA, dsRNA, positive... of virus. RNA genomes can be transcribed into mRNA, directly translated into proteins, or, in the case...
  47. PiggyBac-ing Through the Genome Editing Field

    Type
    Blog Post
    Published
    May 31, 2016, 3:30 p.m.
    ...Correct Path.,” J. stem cell Regen. Biol., vol. 1, no. 1, Jan. PubMed PMID: 26702451. PubMed Central PMCID... 2005 [1]. Like other transposons, piggyBac™ has two components, a transposon and a transposase. The piggyBac...integration [8].   Figure 1: Mechanism of the piggyBac™  transposase/transposon gene modification system...limit [1]. The piggyBac™ technology can be used for numerous applications, including transgenesis, gene-trap...The predicted frequency of ‘TTAA’ in the genome is 1 in every 256 base-pairs of DNA sequence, making it...technologies and strategies for their projects. References 1. L. E. Woodard and M. H. Wilson, “piggyBac-ing models...titrating the transposase to transposon ratios. High ratios of transposase to transposon result in a greater...
  48. Viral Vectors 101: Virus Safety

    Type
    Blog Post
    Published
    June 22, 2023, 1:15 p.m.
    ...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...looks like the genetic cargo in one plasmid (the transfer plasmid), the envelope (Env) gene on a separate... plasmid). Viral production then proceeds by transfection of all three plasmids into a producer cell line...
  49. Plasmids 101: FLEx Vectors

    Type
    Blog Post
    Published
    April 28, 2016, 2:30 p.m.
    ...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...sites directs the Cre recombinase to invert, translocate, or excise a DNA fragment. The availability of...infected and would have the potential to express the transduced reporter gene. Generating a FLEx switch to control...
  50. Some Like it Hot: Thermostable GeoCas9

    Type
    Blog Post
    Published
    Sept. 14, 2017, 12:40 p.m.
    ...buffer at temperatures ranging from 25-80 °C. Activity is expressed as Kcleave (min-1). SpCas9 has maximum...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...outperformed SpCas9 at high temperatures. See Figure 1 for a summary of the experimental results. GeoCas9...). G. stearothermophilus grows at temperatures ranging from 30-74 °C, with an optimal growth temperature...or G) Spacer Length 20 nt 22 nt Temperature Range for Optimal Activity 35 - 45 °C 50 - 70 °C Genome...Harrington et al tested GeoCas9’s editing skills by transfecting HEK293 cells with GeoCas9 or SpCas9 RNP’s and...
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