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  1. CRISPR Challenges: Standardization and Homology Directed Repair

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    ...B. Gurumurthy, and Masato Ohtsuka. Nat Protoc. 13(1) (2018):195-215. PubMed PMID: 29266098 Creating knock-in..., with protocols using dsDNA templates achieving ~1-10% efficiency. Easi-CRISPR uses a long ssDNA template...sub-pathways like synthesis-dependent strand annealing (SDSA) and single-strand DNA incorporation (ssDI). "Easi-CRISPR...These complementary goals are aimed at improving translation of CRISPR technology, but they would also bring...a DNA repair newbie - diagrams of resection and strand invasion are like a foreign language to me. But...supports over 250 genomes, and they just released a brand new CRISPOR manual to kick off 2018! "Mechanisms...
  2. Early Career Researcher Toolbox: Free Online Molecular Biology Tools

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    ...more tools for plasmid mapping and design (Figure 1). Benchling: While you might think of Benchling as...Davis from the University of Utah.   Figure 1: A plasmid map created in SnapGene of Blue Flame plasmid...sequences to sequences in a database ExPASy translation tool: Translates a DNA sequence using all six open reading...Annotates features, BLASTs, aligns, digests, and translates a sequence.   NEBCutter2: For finding restriction...information, such as expression patterns, post-translational modifications and polymorphisms Codon optimization...
  3. Year of the Camelid: Antibody Style

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    ... similar antibodies in llamas and alpacas (Figure 1). At the time, researchers were already on a quest...nanobodies (Arbabi-Ghahroudi, 2017)!      Figure 1: Comparison of a heavy-chain only antibody and single-domain... tools for diverse applications. For example, RANbodies can be used as an alternative to conventional ...sdAbs were used to create GFP scaffolds for transcriptional activation.  sdAbs in the clinic sdAbs have...also been some interesting work done developing transgenic mice that express camelid variable domains (aka...Llamas Required - Synthetic Nanobodies Against Membrane Proteins More resources from addgene.org  Plasmids...
  4. Hot Plasmids and Viral Preps - July 2021

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    ...organoid model (Sun, et al. 2021).  Figure 1: Example schematic from the Organoid EasyTag system...without altering that of the internal control (Fig 1). Because this method relies on the fluorescence ratio...B) Strategy for leak-free transcriptional control. C) Iterative transduction workflow overview. Image ... by integrating a SL-insensitive fluorophore (LSSmOrange) as an internal control and a SL-sensitive fluorophore...fluorescent biosensor has a high sensitivity (50 nM-500nM range) and a high specificity for SLs in vitro, and they...
  5. Comparing Cas9 to NgAgo: Can the Argonautes Best CRISPR?

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    ...cleavage. NgAgo takes a different approach, randomly removing 1-20 nucleotides from the cleavage site specified...About NgAgo User's First Impressions Here References 1. Gao, Feng, Xiao Z. Shen, Feng Jiang, Yongqiang Wu...in the cell. gDNA guides will also need to be transfected into the cells of interest. In contrast, RNA ...must be expressed from a plasmid or in vitro transcribed, and changes in gRNA secondary structure can ...removal RNA-guided CRISPR enzymes cause double-stranded breaks, with either blunt (Cas9) or staggered ...
  6. Natural or synthetic? How Addgene’s dataset reveals trends in biological innovation

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    ...from distantly related organisms. In 2006, less than 1% of the genes deposited at Addgene were synthetic....synthetic biology is expanding rapidly.  References 1. Kunjapur, Aditya M., Philipp Pfingstag, and Neil ... synthesis companies often work within a narrow range for GC content. Rare codons also are not good predictors...sequences is Proteobacteria - the most frequent transfer of genes is from Proteobacteria to mammalian expression...natural gene sequence is, the less likely it is transferred into another organism in the lab. Predicting ...
  7. Using Ultrasound to Image Bacteria in vivo: Acoustic Reporter Genes

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    ...optimized for expression in E. coli: acoustic gene 1 (arg1) and acoustic gene 2 (arg2). The key difference... plasmids are available from Addgene! References 1 Bourdeau, R.W., Lee-Gosselin, A., Lakshmanan, A., ...expressing ECN is 109 cells/ml, which is within the range of  the ~1011 commensal bacteria per gram of stool...
  8. CRISPR 101: Which Cas9 Do I Choose for My CRISPR Experiment?

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    ...this system.  Fig. 1: Cytidine deamination takes place on the free strand of DNA and converts a C...guide RNA (sgRNA), provided it meets two conditions:  1) The sequence is unique compared to the rest of the...temperature-controlled genome editing. Nat. Commun. 2017 81 8, 1–9 (2017).Walton, R. T., Christie, K. A., Whittaker...changing its double-strand cut to a single-stranded nick. In order to produce a double stranded break, two sgRNAs... target DNA. The reverse transcriptase polymerizes DNA onto the target strand based on the sequence of...targeting dCas9 to transcriptional start sites was sufficient to repress transcription by blocking its initiation...approach is that two sgRNAs targeting opposite strands must be available in moderate proximity to each...
  9. Plasmids 101: Plasmid Incompatibility

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    ... RNAs inhibit plasmid replication.   Figure 1: The replication problem. Iterons are repeated ...actually does, and neither plasmid is maintained (Figure 1).  The partitioning problem Plasmid incompatibility...Agrobacterium tumefaciens. Genes & Genetic Systems 77:1–9 . https://doi.org/10.1266/ggs.77.1 Pubmed PMID: ... and inhibit its own transcription. As copy number increases, RepA transcription is repressed and replication...indirectly inhibit replication through inhibiting translation of replication machinery proteins, or directly... division. They don’t simply rely on chance (or random diffusion) to make this happen.  There are several...CBPs and NTPase to go around, the plasmids are randomly positioned, leading to plasmid loss (Diaz et al...
  10. Hot Plasmids: Fall 2024

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    ...and is recommended for use in western blots (Figure 1). If you prefer to produce your own antibody or want...are also available from Addgene!   Figure 1: Experimental validation for Anti-V5 [IPI-SV5-Pk1]...biophysical studies of protein degraders. Nat Commun., 15(1), 8885. https://doi.org/10.1038/s41467-024-52871-9... the P and V proteins of Simian virus 5 (SV5) (Randall et al., 1987). The epitope (GKPIPNPLLGLDST) has...10.57733/addgene.l0ulu4. Hanke, T., Szawlowski, P., & Randall, R. E. (1992). Construction of solid matrix-antibody-antigen....org/10.1099/0022-1317-73-3-653. PMID 1372038. Randall, R. E., Young, D. F., Goswami, K. K., & Russell...functional properties, and is amenable to a wide range of biophysical assays (Kroupova et al., 2024). They...
  11. Tips for Getting a Faculty Position

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    ...sentences) What will be the focus of your first grant? (1-2 sentences) Simply stated, what are your...Full "Applying for a Faculty Position" eBook Here 1. Have a competitive CV You don't necessarily need ...that people would agree is important to understand. (1-2 sentences). For example: Distinguishing correctly...emphatically deny that I have a magic formula to guarantee a reader the faculty job of his/her dreams. There...currency of scientific success is publications and grants. 2. Write succinct and easy to understand documents...years. You will discuss the focus of your first grant, how you will overcome certain obstacles, alternative...It's not about you and how you will finally be granted the faculty position you have craved since grad...
  12. Hot Plasmids - October 2022

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    ...protein sequence of the predecessor GEVIs (called ASAP 1 and 2), they found an indicator that is optimized ...several other constructs in plasmid form. Fig. 1: Summary of the approach and outcomes of the screen...voltage indicator: JEDI-2P  by: Brian O'Neill  The François St-Pierre lab and collaborators have successfully...photoactivation of HcKCR1 in mouse neurons. D) Membrane voltage traces of action potentials in a HcKCR1...
  13. Tips for CRISPR Gene Editing in Mice

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    ...screening for the best gRNA Figure 1: Validation of double strand break (DSB) mediated homology dependent...as control (Cetn1/sgRNA1), 2; darker than control, 1; very dark). Brighter fluorescence indicates a more...and greatest in scientific content.      References 1. Cho, Seung Woo, et al. "Analysis of off-target effects...repair (HR, homologous recombination; SSA, single strand annealing) took place and reconstituted the EGFP...site. (c) The pCAG-EGxxFP target plasmid was co-transfected with pX330 plasmids containing sgRNA sequences...efficacy of your gRNAs is then a simple matter of transfecting HEK293T cells with your modified pCAG-EGXXFP...fluorescence, the better that gRNA is at causing a double stranded break at the target site, allowing the two halves...
  14. Important Considerations in Optogenetics Behavioral Experiments

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    ...derekpsimonphd.    References 1. Stuber, Garret D., et al. "Excitatory transmission from the amygdala to nucleus...animal will repeatedly nose-poke at the active hole [1, 2].    Place preference/place aversion also models... can be explained primarily in two different ways 1) your hypothesis is wrong or 2) there is some problem...examples I’m personally interested in include: intracranial self-stimulation (ICSS) and place preference...(viral expression, efficiency of laser light transmission to the target neurons, appropriate stimulation...optogenetics is performed in this species. However, transgenic rat technology is improving and may one day reach... reach the sophistication of mouse transgenics. Everything that has been described is intended for the...
  15. Sharing Your Lab Protocols: Using Apps to Save Time & Track Your Experiments

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    ...Recently I learned that Addgene’s pLKO.1 cloning protocol is viewed around 3,000 times each month. I ...on the Addgene website in December 2006, the pLKO.1-TRC cloning vector (deposited by David Root of the...would the thousands of other scientists using pLKO.1 variants learn about those updates? This is a problem...restriction digest of plasmid DNA, and bacterial transformation. And more plasmid-related educational resources...
  16. Fluorescent Proteins 101: Luciferase

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    ... are not required to initiate the reaction. Table 1 compares some general advantages and disadvantages...disadvantages of luminescence versus fluorescence.  Table 1: Properties of Luminescence versus Fluorescence   ...codon, which is then transfected into the desired cells. A hybrid mRNA transcript containing luciferase...luciferase, usually serves as an indicator of transcription within cells, where detection of the reporter...Higher Lower Background Lower Higher Post-translational Modification Not Required Required Photobleaching...regulatory elements, such as promoters, enhancers and untranslated regions, or the effect of mutations of these...as the most efficient means to disrupt the cell membrane and deliver the substrate; however, secreted luciferase...
  17. Quantifying DNA? Here are Five DNA Quantification Methods to Consider

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    ...automated. Unlike gel electrophoresis, you only need 1-2 ul of sample and the run time is just a few minutes...quantified first before larger fragments. Figure 1: The quantification of a RNA ladder using capillary...This method involves measuring the absorbance/transmission of light through a liquid to determine the concentration...spectrophotometer measures these absorbances using UV-transparent cuvettes. First you measure the absorbance of...PicoGreen or SYBRGreen, are specific for double strand DNA (as compared to spectrophotometric methods ...However, the measurements are made in the visible range and can be read with a standard ELISA reader if ...
  18. Hassle-free 96-well Format Epitope Tagging Using Cas9 Ribonucleoprotein

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    ...References 1. Bressan RB, Dewari PS, Kalantzaki M, Gangoso E, Matjusaitis M, Garcia-Diaz C, Blin C, Grant V, ...the tag sequence flanked by homology arms (Figure 1). In the first step of optimization, we started off...form the ribonucleoprotein complex (csRNP, Figure 1). We use in-house purified Cas9 protein, which, in...standard immunocytochemistry (ICC) assays.  Figure 1: Three ingredients of epitope-tagging experiments....binding to the template strand (strand used by RNA polymerase II for transcription) are more effective for...complex. This complete transfection mix, i.e. csRNP plus ssODN, is then transfected into stem cells. Cells... were transfected in 96-well format using an Amaxa Shuttle device; 5 days after the transfection, the ...
  19. An Addgene Summer Internship

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    ...two weeks, we were able to obtain eight clones. We ran digested and undigested samples of the clones on ...intern to complete and present on.    Figure 1: Addgene's summer interns presenting their capstone...and I wouldn’t want it any other way. Toj Toj-Villagran is a rising senior in high school who just completed...
  20. New Norepinephrine Indicators: nLightG and nLightR

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    ...nLightR (Kagiampaki et al., 2023).     Figure 1: Properties of nLightG and nLightR. A, Structural ...Article 6. https://doi.org/10.1038/s41592-022-01488-1 More resources on the Addgene blog Fluorescent proteins...generating variants with improved affinity and dynamic range of both nLightG and nLightR, and may soon have a...
  21. Antibodies 101: Avoiding the Mouse on Mouse Mess in IHC

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    ...following three strategies might help!     Figure 1: Species on species staining can be a problem because...same host species as your secondary antibody since 1) your secondary should not recognize Fab fragments...References and Resources References Goodpaster T, Randolph-Habecker J (2013). A Flexible Mouse-On-Mouse Immunohistochemical...
  22. How to Negotiate a Successful Lab Start Up Budget

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    ...your budget, you should take the following steps: 1. Define your timeline Start with your thesis in mind...these decisions in the following order of importance: 1. First make decisions based on experimental timelines... several factors aren’t taken into consideration. 1. Always focus on the science When negotiating finances...will take to secure your first (R-level) research grant.  Set your timeline from there, then start identifying...techs’ financial books.  To find personnel salary ranges, go to online job information sites (like, indeed.com...
  23. Scientific Peer-review: Providing Critical and Kind Feedback and Advocating for Open Science

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    ...the journal-specific guidelines.  Peer-review step 1: The first read At the first read of the paper, I ...group of Prof. Mark Tester, where she focuses on (1) salt-induced changes in root-to-shoot ratio in Arabidopsis... discipline and reduces the dissemination of unwarranted claims or unacceptable interpretations. A good...studying plant development and abiotic stress tolerance, I have been peer-reviewing journal submissions...
  24. Plasmid Cloning by PCR

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    ... by PCR has error rates that range from roughly 1 per 500bp to roughly 1 per 10 million bp depending on...chance for mis-priming, so you can use a pretty wide range of annealing temperatures, but you may need to increase...
  25. Even more elegant: Single injection CRISPR/Cas9 in C. elegans

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    ...sequences are inserted into the genome. Figure 1: Self-excising cassette schematic from Dickinson et...):1028-34. doi: 10.1038/nmeth.2641. Epub 2013 Sep 1. PubMed. Find plasmids from this publication at ...can generate a fluorescent protein fusion, transcriptional reporter, and loss-of-function allele in just...markers. Bob Goldstein’s lab previously used a transgene selection strategy for their C. elegans/CRISPR...
  26. Revamp Your Lab Meetings With Creative Virtual Collaboration

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    ...those ideas and build from those.   Figure 1: Virtual lab meeting? No problem! You can still creatively... on it – so it is important to take breaks. After 1 hour (or another designated time) of meeting, someone... creativity are pivotal in writing publications/grants too. As described by several works (Wuchty et al...and do a quick break to chat. This can be done randomly or manually assigning which participants to group...
  27. Plasmids 101: Inducible Promoters

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    ...Hsp70, the heat shock releases heat shock factor 1 (HSF-1), which subsequently binds to heat shock elements... polymerase and transcription factors. Since the promoter region drives transcription of a target gene...promoter to induce transcription of the phage repressor cI. Repressor cI inhibits transcription from phage promoter...lag time due to the time needed for transcription/translation. Many thanks to Nicole Zurcher who contributed... the promoter, turning it ON and initiating transcription.     Negative inducible In the OFF state, the...a bound repressor protein actively prevents transcription. Once an inducer binds the repressor protein...the DNA. With the repressor protein absent, transcription is turned ON. Types of inducible promoters Chemical...
  28. Viral Vectors 101: The AAV Retrograde Serotype

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    ... There are two methods of neuronal tracing (Fig. 1): one to visualize neurons that send information to...significantly updated in 2023 by Jason Nasse.  References 1. Tervo, D. Gowanlock R., et al. "A designer AAV variant...neurons! Neurons are really cool because they can transmit information, for example, from one of the 180 ...associated virus (AAV) shows relatively low retrograde transport efficiency in most serotypes. Some viruses (e....e.g., rabies) naturally exhibit retrograde transport and can therefore perform retrograde tracing, but...efficiently infects neurons, directs high-level transgene expression, and has retrograde functionality to...genetically controlled function. By using AAVrg in Cre transgenic mouse lines, you can access and manipulate an...
  29. Fluorescent Proteins 101: GFP Fusion Proteins - Making the Right Connection

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    ...sticks out and can be considered a linker (figure 1). In fact, for several FRET biosensors (yellow cameleon...fluorescent protein are relatively close together (figure 1). Where should the fluorescent protein be inserted...fluorescent protein database." Nature methods (2019): 1. PubMed PMID: 30886412. Mastop, Marieke, et al. "A...et al., 2018). Unbiased, random insertions can be generated with a transposon-based strategy (Sheridan...fluorescent fusion proteins: random insertion of GFP with an in vitro transposition reaction." BMC neuroscience... This type of interference is known as steric hindrance. For instance, GFP may occlude catalytic sites...sites or motifs that are necessary for post-translational modifications. Despite these potential issues...
  30. Evolution of Lab Techniques

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    ...blotting, named for its inventor Edward M. Southern (1), can be used to detect DNA identity, size, and abundance...hours at low cost with restriction mapping (Figure 1). Though some labs may prefer to send DNA directly... serotonergic system and behavior.     References 1. Southern, Edwin Mellor. "Detection of specific sequences...into smaller pieces, run on a gel, and transferred to a membrane for analysis through hybridization of ...researchers generating transgenic animals may choose Southern blotting to screen founder transgenic animals for ...techniques used to generate transgenic mouse lines, such as BAC transgenic or traditional knockins/knockouts... control sample. Southern blotting applications range from confirming the results of cloning or knockout...
  31. CRISPR Guide Update

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    ...refreshed figures made using BioRender.com. Figure 1: PRIME editing Please check out the updated guide... to use CRISPR plasmids in the lab and the vast range of possibilities at their disposal. With this update...CRISPR’s ability to make large genome edits using transposases or the Cascade-Cas3 system. We also describe...
  32. Building and Validating Recombinant Antibodies: A Case Study

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    ...restriction digest and colony PCR.   Fig. 1: (A) Schematic of cloning, expression and validation... doi: 10.1371/journal.pone.0038313. Epub 2012 Jun 1. PMID: 22675541; PMCID: PMC3365890....-mAbs. It was recognized that an aberrant IgG light chain transcript was expressed by some of the hybridomas...heavy (blue) chains as driven by two CMV promoters (orange). Figure from Andrews, et. al., Elife  A limitation...IF-ICC.) This method was chosen because cells transfected with a plasmid to express the target antigen ...the restriction enzyme BciVI was present in the aberrant light chain sequence, but was predicted to occur...express multiple subclasses of IgG antibody. Broad range secondary antibodies are commonly used in research...
  33. Five Popular Model Organisms, Part 2

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    ...research like metabolism. Transport, biofilms, and much more. Because of it’s BSL-1 status, E. coli can be...oxygen. Additionally, its status as a Biosafety Level 1 microbe makes it a perfect candidate for introductory...with superior performance. Nature Communications, 9(1). https://doi.org/10.1038/s41467-018-04899-x Yokoyama...plasmids for use in CRISPR and Tol2 transposase induced transgenesis.  Xenopus Xenopus, or frogs, are one...have created molecular biology tools to generate transgenic axolotls for an array of different studies. Elly...popular tools for studying frogs include egg transplants and microinjections. Injections of mRNAs, for...Arabidopsis. There are also important tips for plant transformations and the use of Arabidopsis in the classroom...
  34. Crowdfight, a Platform to Boost Scientific Collaboration During COVID-19 and Beyond

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    ...prompted us to create Crowdfight.   Figure 1: Crowdfight is a community of scientists who believe...collaborator for a specific task, Crowdfight will: 1) Find an expert with the right skill; 2) Confirm the...with viruses or transmissible diseases, so we were left with no choice but to quarantine in our houses,...simpler and the volunteers helped with things like translations, bibliographic searches, etc.     Expanding...we call “asymmetric collaborations.” These are transient partnerships where a researcher makes a small ...blog post about remote collaborations Read our Transferable Skills Guide article about external collaborations...
  35. Advice on Career Paths and the Green Card Process for International Researchers and Entrepreneurs

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    ...of an industry H-1B need to be aware of the April 1 deadline for companies to submit an application on...and non-profit organizations do not have the April 1 H-1B queue process or quota like industry, these organizations... National Interest Waiver. The three prongs are: (1) The foreign national’s proposed work endeavor must...-1B, you need to prove 3 threshold requirements: (1) that you have international recognition for your ...the non-profit sector are transferrable to industry such as technology transfer, communications, medical... minimum (8 U.S. Code § 1184 - Admission of nonimmigrants). The foreign worker must possess at least a...and therefore the academic H-1B visa cannot be transferred to an industry position. If you cannot get an...
  36. Viral Vectors 101: Gamma-Retroviral Packaging Systems

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    ...additional flexibility in pseudotyping.   Figure 1: Genome of a prototypical gamma-retrovirus.    ...an SV40 promoter, and Neomycin selection.   Table 1: Gamma-retrovirus glossary Plasmid Type Element...γ-Retroviral transfer plasmid encoding a transgene, sgRNA, or shRNA of interest: The transgene sequence is...packaging and transduction are not encoded by the transfer plasmid, but instead are provided in trans by other...integrated into the host genome upon viral transduction. Most transfer plasmids available from Addgene were ...packaging, and transfer) are supplied by three types of plasmids, which are cotransfected into the 293T...cell line. γ-Retroviruses can transduce target cells, but the transduced target cell does not produce ...
  37. All in a Twist: dsRNA

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    .... Fig. 1: Exogenous sources of dsRNA Cellular sources of dsRNA Transposable elements such ... 286-301 (2022). doi.org/10.1038/s41580-021-00430-1 More resources on the Addgene blog CRISPR 101: RNA...Transcription, translation, and prone to degradation – those are the words that describe RNA! Double ...in our cells in the single strand form, but double stranded RNA and RNA:DNA hybrid molecules both exist...arise from a ssRNA engaging one strand of a dsDNA molecule; the 3-stranded structure produced is known as...intermediates in the process. These transcription-coupled R-loops are transient in nature and will dissociate...dissociate when gene transcription is complete. However, transcription of thousands of genes is constantly occurring...
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