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  1. Viral Vectors 101: Transductions

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    Blog Post
    ...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...
  2. Plasmids 101: Control Plasmids

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    ...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...
  3. Quick Guide to All Things Lentivirus

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    ...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. "...
  4. Hot Plasmids June 2018 - Reverse transcriptase, nanobody, and protein-DNA interaction tools

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    ...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...
  5. Visualizing Translation at the Single Molecule Level

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    ... 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...
  6. Scientific Reproducibility - Focusing on Solutions at the Minisymposium on Reproducibility

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    ... 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...
  7. Technical Design of a Western Blot

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    ...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...
  8. Droplet Digital PCR for AAV Quantitation

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    ...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...
  9. Fluorescent Tagging of Endogenous Genes with SapTrap

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    ... 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...
  10. Antibodies 101: Producing Recombinant Antibodies

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    ...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...
  11. Sleeping Beauty Awakens for Genome Engineering

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    ...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...
  12. 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...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  ...
  13. Tips for Titering Your Lentiviral Preps

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    ...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...
  14. Negative Can Be Positive: Open AAV Data with Addgene

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    ...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...
  15. CRISPR Antimicrobials

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    ..., 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...
  16. Plasmids 101: Gateway Cloning

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    ...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...
  17. Getting to Know Expansion Microscopy

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    ...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...
  18. Viral Vectors 101: What is a Virus (and a Viral Vector)?

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    ... 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...
  19. 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... 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...
  20. 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...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...
  21. 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...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...
  22. Some Like it Hot: Thermostable GeoCas9

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    ...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...
  23. HA Frankenbody, a New Imaging Tool to Visualize Single Molecules and Nascent Peptides

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    ...HA-tagged proteins in vivo. Nature Communications, 10(1). PubMed PMID: 31270320. PubMed Central PMCID: PMC6610143...fused to a fluorescent protein. “Frankenbody,” like the infamous frankenstein, was constructed by grafting...called this probe the HA frankenbody (Zhao et al., 2019).  To develop HA frankenbody, the Stasevich lab tested...can you do with the HA frankenbody? Another large advantage of the HA frankenbody is that it remains bound...also proved that HA frankenbody can be effectively used to track single mRNA translation in U2OS cells. HA...acids, thus it is translated quickly by the ribosome. This feature provides HA frankenbody the ability to...properly once inside cells.  Developing the HA frankenbody To combat the issues with these antibody based...
  24. Viral Vectors 101: Pseudotyping

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    ...tail.   Figure 1: Lentiviral production uses three plasmids: (1) The transfer plasmid, (2) the envelope... 2017)  Table 1 (Gutierrez-Guerrero et al., 2020) Table 1 (Cronin et al., 2005)     References and ... on different viral membranes, tropism, and advantages and disadvantages: Table 1 (Joglekar et al., 2017... specific purposes as described previously (Table 1, Gutierrez-Guerrero, et al, 2020). Because retrovirus...lentiviral vector to be transported retrograde and also has higher neuronal transduction efficiency and a better...virus to either restrict or broaden the host cell range (tropism). Pseudotyping is only done on enveloped...plasmid, and (3) the packaging plasmid. These are transfected into target cells which produce lentiviral particles...
  25. Controlling for Off-target Effects with a New Genome-wide CRISPR Screen Design

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    ...holds true in genome-wide screens.   Figure 1: Summary of the advantages of the new approach to ... in both screens, with the growth screen having a 1% false discovery rate and identifying >88% of previously...in Morgens et al. contains three types of guides: 1) targeting guides (blue), which target all protein-coding...off-target sites was profiled. Guides with exact or 1-bp mismatch off-targets had greater toxicity than ...characteristics that influence gRNA off-target activity: 1) mismatches closer to the PAM are less tolerated than.... When comparing the toxicity of guides that have 1-bp mismatch off-target sites, short guides had reduced...Knockout Library are available from Addgene! References 1. Morgens, David W., et al. "Genome-scale measurement...
  26. 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...is composed of single stranded DNA, which is particularly well suited for strand invasion, a key step ...
  27. Using AAV for Neuronal Tracing

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    ...). Analysis of transduction efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and...serotypes 1, 8 and 9 share conserved mechanisms for anterograde and retrograde axonal transport. Hum Gene.... (2009). Comparison of transduction efficiency of recombinant AAV serotypes 1, 2, 5 and 8 in the rat ... Brain Res 406(1-2), 317-321. PubMed PMID: 2436717. Towne, C., Schneider, B.L., Kieran, D., Redmond, D.E.Jr...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...
  28. Luciferase Plasmid Collection

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    ... Eric Campeau 21474 pLenti CMV V5-LUC Blast (w567-1) Firefly CMV Lentiviral expression of firefly luciferase...dynamic range, and resistance to photobleaching has made luciferase a common choice in assays ranging from... luciferase. Transcriptional Element Screening Optimized STARR-seq ( S elf- T ranscribing A ctive R egulatory...including transcriptional reporters for NF-kb, TGF-b, c-Myc, p53 and MAPK/JNK transcriptional reporters...collection of luciferase plasmids for assays of transcriptional regulation and bioluminescent reporters. Plasmid...bioluminescence found in a diverse number of organisms, ranging from bacteria to aquatic animals to insects. Luciferase... protein half-lives, making them useful as transcriptional reporters. However, they are not secreted, ...
  29. Pathways Over Time Plasmids Engage Students in Functional Genomics Research

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    ...authentic research experiences to undergraduate students (1, 2), but educators face significant challenges 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...students first transform the S. cerevisiae met deletion strains and then isolate transformed strains on media...organism into overexpression plasmids. Students next transform deletion strains from the reference organisms ...
  30. CRISPR 101: Non-Homologous End Joining

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    ...842 . https://doi.org/10.1016/j.molcel.2014.08.002 Ran FA, Hsu PD, Lin C-Y, Gootenberg JS, Konermann S, ...Last updated Sept 1, 2020. This post was contributed by David Wyatt and Dale Ramsden, UNC at Chapel Hill...the course of repair by NHEJ are typically small (1-10 bp) but extremely heterogeneous. There is consequently... single strand break; when two such breaks are introduced near each other, in opposite strands. This “...Cas9 can be easily programmed to make a DNA double strand break (DSB) in the genome wherever the user chooses....org/10.1371/journal.pgen.1000683 Bétermier M, Bertrand P, Lopez BS (2014) Is Non-Homologous End-Joining...Giovannangeli C, Jasin M, Brunet E (2014) Chromosomal Translocations in Human Cells Are Generated by Canonical Nonhomologous...
  31. Bacterial Expression Systems

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    ...expression inducible by red light. pCph8 50552 pLtetO-1 Anhydrotetracycline Jeffrey Tabor Anhydrotetracycline...testing transcription factor binding to reporter plasmid pH3U3-zif268 (omega) . Transcription factors ... answer many interesting questions. Does my transcription factor bind to a particular sequence? Do these...wild-type Cas9 from S. pyogenes for inducing double stranded breaks. For a more comprehensive list of our bacterial...see here . pGRG Series Various Plasmids Tn7 Transposition Nancy Craig A gene of interest cloned into one... one of these plasmids can be transposed into the attTn7 attachment site found in many enterobacterial...enterobacterial genomes. The bacteria of interest are transformed with the appropriate construct, grown at the permissive...
  32. Optimizing Donor DNA for Enhanced CRISPR Genome Editing

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    ...the four strands of the cleaved duplex, while the fourth strand (the released strand in Figure 1 below) ...complementary ssDNA molecules in vitro. Figure 1: Cas9 binding to the cleaved DNA duplex. Image from...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...discovered that single stranded donor DNA: Complementary to the released strand, 127bp in length, With...single or double stranded donor DNA with other design parameters. Example single stranded donor DNA and ...presented in Figure 2. Figure 2: Single-stranded donor DNA interaction with the Cas9-DNA duplex...
  33. The Importance of High Titer for AAV Transductions

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    ...methods to improve AAV production.     References 1.Clark, K. Reed. "Recent advances in recombinant adeno-associated... The higher the titer, the better. AAV transport and transgene expression It’s clear that we need high...be required. For example, retrograde AAV gets transported up the cell’s axon. While the mechanism for this...yet fully understood, we can imagine that this transport is probably not 100% efficient. So the few AAV... higher retrograde AAV titers for successful transduction. In another example, neuronal gene expression..., fewer channel proteins are required for the transduced cell to become light responsive than fluorescent...process of generating viral particles. Limit tube transfer - the fewer opportunities your viral particles...
  34. Improving Transduction Efficiency with Exosome AAVs

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    ...vector-exosomes), exosome AAVs, or exo-AAVs (Figure 1). The researchers discovered that these particles ... are often found with cellular exosomes, small membrane vesicles or microvesicles (approx. 40 - 150 nm... diameter) that are secreted from the cellular membrane into the culture medium. AAV particles are either... vectors. They found that they have a higher transduction efficiency, i.e. the same number of AAV particles...to modify it to improve yields. For example, transfecting the producer cell line with an expression vector...proteins, nucleic acids) which possibly improve transduction properties. György and colleagues found that...that the association of AAV particles with membrane vesicles protects them from antibody recognition and...
  35. CRISPR 101: Homology Directed Repair

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    ...Genome engineering using the CRISPR-Cas9 system. Ran FA, et al. Nature Protocols Nov;8(11):2281-308; (2013)...oligodeoxynucleotides)) are commonly used for smaller modifications (~1-50 base pairs). Small edits require as little as 30...Easi-CRISPR was shown to increasing editing efficiency from 1-10% with dsDNA to 25-50% with ssODNs in mouse models...ribonucleoproteins. Quadros RM, et al. Genome Biol. 18(1); (2017). PubMed.  Additional Resources on the Addgene...dHJs are four-stranded branched structures that form when elongation of the invasive strand “captures” and...lesion results from breakage of both DNA strands - a double-strand break (DSB). DSBs can be caused by intracellular...proteins required for strand invasion and a primer for DNA repair synthesis. The ssDNA strand then displaces ...
  36. Which Fluorescence Microscopy Techniques is Best for Me?

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    ... microscopy contrast technique in modern biology (1). When performed correctly, fluorescence microscopy...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...
  37. Twenty Years of Sharing: Expanding Accessibility

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    ...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...material is right for their experiment.     Table 1: Most popular guides, protocols, and collections of...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... package stays in transit for a certain number of days and tracking average transit time for each courier...
  38. 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...this type of experimentation to the eventual translation to the clinic and cures. There is no doubt that...
  39. Deep Dive: qPCR

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    ...Issue 19, 1 October 2000, Pages 3752–3761, https://doi.org/10.1093/nar/28.19.3752Wong M; Medrano J. Real-time...relatively easy to multiplex (Thellwell, 2000). See Table 1 for a comparison of features of several commonly used...in primer Yes Yes Agarose gel Table 1: Features of various qPCR chemistries. Adapted from...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...
  40. Making CRISPR Plasmids Using Fragmid

    Type
    Blog Post
    ...building it! Table 1 has a list of Fragmid destination vectors currently available. Table 1: Fragmid destination...components on the Fragmid website.   Figure 1: (Top) Schematic overview and timeline of the Golden... CRISPR vector the Fragmid way!    Figure 1: Selecting your vector type on the Fragmid website...components available will depend on your answers in step 1, so you’ll only be able to select components that ...Gate cloning, perform an exonuclease cleanup, transform, plate, and pick. In short, the Fragmid system...AAV pRDA_889 (ITRs from AAV2) Mammalian Transposon pRDA_757 (Piggybac; constitutive expression...   Drosophilia Plasmid pRDB_053 (for transgenic flies; gypsy insulator sequences; white + selectable...
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