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  1. Typing CRISPR Systems

    Type
    Blog Post
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    March 18, 2025, 1:15 p.m.
    ...   Class 1 versus class 2 There are two CRISPR classes: Class 1 and Class 2. Class 1 CRISPR systems use...systems to carry out various functions. Class 2 Class 2 CRISPR systems rely on a single protein Cas effector...explore Class 2 CRISPR in more depth, the Jennifer Doudna lab maintains an encyclopedia of Class 2 CRISPR systems...systems: a burst of class 2 and derived variants. Nature Reviews Microbiology, 18(2), 67–83. https://doi.org...complex for antiviral defense) complexes, while Class 2 use single protein Cas effectors, like Cas9. The Cascade...1 remains largely underutilized compared to Class 2. Class 1 Despite their incredible abundance, Class...components present in the Cascade complex. Figure 2: Schematic of a Cascade complex (blue subunits) with...
  2. Viral Vectors 101: The Retroviral Lifecycle

    Type
    Blog Post
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    July 27, 2023, 1:15 p.m.
    ...that have been developed into retroviral vectors and 2.) a subclass of retroviruses called the lentiviruses...effectively. Retroviral structure   Figure 2: Structure of a retrovirus. Image re-used from Dong...Dong & Kantor, 2021 under CC-BY license. Figure 2 gives a detailed view of the structure of a retroviral...transfer of RT, which would actually occur in step 2 during uncoating. After uncoating, reverse transcription...one of the two strands’ DNA counterparts from step 2 will be integrated by the viral integrase protein ... Air. Environmental Science & Technology Letters, 2(4), 84. https://doi.org/10.1021/ACS.ESTLETT.5B00050...the virus and isolation of the nucleic acid. Proceedings of the National Academy of Sciences of the United...
  3. Alex Chavez on MD PhDs, CRISPR, Gene Drives, & More

    Type
    Blog Post
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    Nov. 15, 2016, 3:30 p.m.
    ...Topic) 0:00 - 2:00 : Introduction to the podcast from producers Tyler Ford and Eddy Page. 2:00 - 3:55 : ...: Alex describes the MD PhD process and explains why he loved the first 2 years of medical school. 7:05.... Listen to this episode for insights into the process of getting an MD PhD, the inside scoop on developing...
  4. Addgene is Expanding Our Viral Vector Service!

    Type
    Blog Post
    Published
    Oct. 15, 2024, 1:15 p.m.
    ...Request review: 1–2 days Prep and QC completed: 6–8 weeks Average shipping time: 1–2 days (USA); 3–4 days...compatibility with our production process. This process will take 1–2 days, and we anticipate approving... that this ordering process will look slightly different from our standard process. We’ll walk you through... 2025.  What will the ordering process look like?  The ordering process is split into two steps, requesting... different serotypes.   Figure 1: The process of requesting and ordering a Packaged on Request... via email. There is no charge for the request process.  Ordering If your request is approved, you will...
  5. Plasmids 101: Secondary Nanobody Toolbox

    Type
    Blog Post
    Published
    Feb. 27, 2018, 2:04 p.m.
    ...antibody has an antigen binding site for a total of 2 binding sites per antibody. C) IgG’s are big enough...enough that multiple labels (green circles in figure 2 below) can be attached to each antibody. But being...displacement Require separate incubation of 1° and 2° Must use different species and/or different IgG ...Greater resolution due to lower label displacement 2° incubation can be skipped by pre-binding to 1° ...a fluorescent tag and the target antigen to about 2 nm, which can lead to higher resolution for super-...subclass.   Express the Nanobody In Bacteria: Table 2 also has a link to the plasmid you’ll need to express... Find plasmids from this publication at Addgene. 2. Bates, M., Böhning, M.I., Chug, H., Görlich, D., ...
  6. Easi-CRISPR: Generating Knock-In and Conditional Mouse Models

    Type
    Blog Post
    Published
    April 5, 2018, 12:42 p.m.
    ...mutations, the 8-10 month process of conventional gene targeting is lowered to about 2-3 months. But certain...included in the final ssDNA template. Figure 2: Overview of ivTRT to generate an ssDNA repair template... floxed conditional allele requires you to target 2 loxP sites to intronic regions 0.5 - 0.8 kb apart....Typically, Easi-CRISPR works best with insertions of 2 kb or less. Luckily, most of the commonly used cassettes... induction systems (ttA or rtTA) are between 1 to 2 kb in length. There are plenty of Addgene plasmid ...create the ssDNA construct as described in Figure 2.  You can also use Addgene plasmids to purify Cas9...generation easi-er! Generating mice before CRISPR The process of generating knock-in mice pre-CRISPR was very...
  7. Genome-wide Screening Using CRISPR

    Type
    Blog Post
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    Aug. 18, 2015, 2:30 p.m.
    ...screen using CRISPR libraries is a multi-step process (see Fig. 2). In most cases, CRISPR libraries are provided...targeting a specific gene within the genome (see Fig. 2). Individual gRNAs are designed in silico using publicly...mouse, human, fly, E. coli, and T. gondii genes.  2) What genetic modification are you trying to make?... is included on the gRNA-containing plasmid, or a 2-plasmid system in which Cas9 must be delivered separately...uncontrolled cell growth, such as cancer. Figure 2: The CRISPR library must be amplified (A) to be used...genes or entire pathways in a particular disease process. While CRISPR is certainly not the first means ...
  8. The Effect of COVID-19 on Liu Lab Plasmid Requests From Addgene Data

    Type
    Blog Post
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    July 16, 2020, 1:15 p.m.
    ...month, from 1/22/20–2/23/20, where there were zero plasmid requests. Afterwards, from 2/24/20–3/15/20 (the...Each paper has between 1–32 plasmids and a total of 2–2,590 requests. We received plasmid requests from ...observed between Jan. 1 and Mar. 1, 2020. Figure 2: A simple approximation of the effect of COVID-19 ...However, it is evident that if we believe that 1/22/20–2/23/20 are the more accurate dates of lockdown in China...Poisson process into two components: 𝜃x(t) and 𝜓z(t). 𝜃x(t) describes the exponential decay process we ...statistical independence assumption of the Poisson process. This modification also eases the interpretation...
  9. The Materials Science of Optogenetics Experiments

    Type
    Blog Post
    Published
    Sept. 17, 2015, 2:30 p.m.
    ...different steps and materials required for each [1, 2]. This protocol [3] provides, in exquisite detail,...stimulation         In the video above, Channelrhodopsin 2 (Chr2) has been expressed in the motor cortex of a...lasers are relatively cheap and will run you about $2-3,000/laser. However, an important caveat is that ... the light-gated cation channel, Channelrhodopsin 2 (ChR2), exists in several states: closed/light receptive...PMID: 21628464; PubMed Central PMCID: PMC3138296. 2. Sparta DR, et al. Construction of implantable optical...board, Jacqueline N Crawley  [et al]. 2012;Chapter 2:Unit2 16. doi: 10.1002/0471142301.ns0216s58. PubMed...animal’s skull using dental cement (a similar procedure as implanting a guide cannula). A fiber optic ...
  10. Common Injection Routes in Mice

    Type
    Blog Post
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    Jan. 22, 2025, 9:42 p.m.
    ...Location: peritoneal cavity Gauge: 25–27 Volume: < 2–3 ml Skill required: intermediate Intramuscular Intramuscular...Location: back or hind legs Gauge: 25–27 Volume: < 2–3 ml (~1 ml per site) Skill required: beginner Intradermal...Intraperitoneal Scruffing Peritoneal cavity 25–27 < 2–3 mL Intermediate Intramuscular Mechanical restrainer...Back or hind legs; between skin and muscle 25–27 < 2–3 mL (~1 mL per site) Beginner Intradermal Anesthesia...Addgene blog Mouse Modeling Part 1 Mouse Modeling Part 2 Five Popular Model Organisms Additional resources ...delivery is also common. Due to the intubation, this procedure is considered quite invasive. Restraint: anesthesia...similar to its intratracheal counterpart, as both procedures target the lungs. The main differences are that...
  11. Flow Cytometry Readouts: Yes, No, and Everything in Between

    Type
    Blog Post
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    Aug. 20, 2024, 1:15 p.m.
    ...low expression, and everything in between (Figure 2). These smears tend to occur when you are looking ...based on your experiment. You can see from Figure 2 that determining where to place your gate based on...the dot plot would be complicated.  Figure 2: (A) a smeary dot plot showing a range of antibody...plot in Figure 4 compared to the dot plot in Figure 2. Quantification using MFI makes it easier to identify...intensity. If your samples and controls were processed the same way, the GFP- population should overlap...samples and control underwent different treatment processes, you may see a shift in the negative population...
  12. Tips for Getting a Faculty Position

    Type
    Blog Post
    Published
    July 20, 2023, 1:15 p.m.
    ... this problem? (2-3 sentences) What will be the focus of your first grant? (1-2 sentences) ...of scientific success is publications and grants. 2. Write succinct and easy to understand documents A...consideration. 3. Present an easy to follow seminar See item 2. Attendees will include grad students (that are solicited...people would agree is important to understand. (1-2 sentences). For example: Distinguishing correctly ...successfully navigated the trials and tribulations of the process, I’ve provided guidance and mentoring to several.... There are too many moving parts in the whole process to distill a one-size-fits-all recipe for success...Student? Get Tips on Getting the Most out of the Process Get more tips from the full eBook Of course there's...
  13. Viral Vectors 101: Optogenetic Tools

    Type
    Blog Post
    Published
    June 27, 2023, 1:15 p.m.
    ...Channelrhodopsin-2, a directly light-gated cation-selective membrane channel. Proceedings of the National...for controlling neuronal activity, channelrhodopsin-2 (ChR2), a blue light-activated cation channel, from...used in tandem with the opsin.      Figure 2: Diagram of excitatory (ChR2) activation by light ...) domains, phytochrome B (PhyB), and cryptochrome 2 (CRY2) (Zhang & Cui, 2015). When stimulated with light...comparative analysis of microbial opsins. Nature Methods, 9(2), 159–172. https://doi.org/10.1038/nmeth.1808 References...comparative analysis of microbial opsins. Nature Methods, 9(2), 159–172. https://doi.org/10.1038/nmeth.1808 Nagel...intracellular signaling pathways. Trends in Biotechnology, 33(2), 92–100. https://doi.org/10.1016/j.tibtech.2014.11.007...
  14. Starter guide to induced pluripotent stem cells (iPSCs) part 1:  A renaissance in regenerative medicine

    Type
    Blog Post
    Published
    Oct. 30, 2018, 1:04 p.m.
    ...them in Regenerative Medicine. Acta Naturae, 2010. 2(2): p. 18-28. PubMed PMID: 22649638. PubMed Central...capability to differentiate into specialized cell types [2]. We general speak of 4 levels of stem cell potency...zygote through to the morula stage are totipotent [2-4]. Pluripotency: When a cell has the ability to differentiate...stem cells (ESCs), which I discuss in detail below [2]. Multipotency: When a cell can differentiate into...PMID: 26726264. PubMed Central PMCID: PMC4686367. 2. Jaenisch, R. and R. Young, Stem cells, the molecular...types makes them useful models for developmental processes and promising therapeutic tools. The two unique...
  15. CasPEDIA: A Functional Classification of Cas Enzymes

    Type
    Blog Post
    Published
    Jan. 25, 2024, 2:15 p.m.
    ...systems: a burst of class 2 and derived variants. Nature Reviews Microbiology, 18(2), 67–83. https://doi.org...resource that provides summary information on Class 2 Cas enzymes. The information is organized in wiki ...this content and much, much more.     Fig. 2 – List of resources and properties for a Cas entry...Database: A Functional Classification System for Class 2 CRISPR-Cas Enzymes [Preprint]. Biochemistry, Biophysics...non-CRISPR-associated host factors required for CRISPR processing. For each enzyme, it will also show you how multiplexed...
  16. MXS Chaining

    Type
    Blog Post
    Published
    Feb. 7, 2017, 3:30 p.m.
    ... TagBFP 399nm/ 456nm histone 2B (H2B) Chromatin 2 Cerulean 433nm/ 475nm Lyn-tag (derived from the tyrosine-protein...based (chaining-based) cloning. The modules (Figure 2) are contained in individual plasmids and are each...between various cloning methods are listed in Table 2. For example,  chaining-based cloning methods require...suitable for combining endogenous sequences. Table 2: High Throughput Cloning Strategies Method Technology...PMID: 20205762. PubMed Central PMCID: PMC2822740. 2. Engler C, Kandzia R, Marillonnet S. A one pot, one...various mammalian promoters), the same cloning procedure can be used to incorporate each element into the...and protein localization, as well as cellular processes like gene expression and cell migration (Sladitschek...
  17. CRISPR 101: Targeting RNA with Cas13a (C2c2)

    Type
    Blog Post
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    Sept. 21, 2017, 2:07 p.m.
    ...question: C2c1, C2c2 and C2c3 (short for Class 2, candidate 1, 2, or 3). C2c1 and C2c3 are related to Cpf1,...however cutting efficiency of Cas13a is reduced when 2 mismatches are present. The protospacer flanking sequence...PMC5127784. Find plasmids from this paper at Addgene. 2. East-Seletsky, Alexandra, et al. "Two distinct RNase... and functional characterization of diverse class 2 CRISPR-Cas systems." Molecular cell 60.3 (2015): 385...specific RNAs out of a pool of RNAs) or studying RNA processing in live cells. Indeed, groups have utilized dCas13...RNase activities of CRISPR-C2c2 enable guide-RNA processing and RNA detection." Nature 538(7624) (2016):270...
  18. Golden Gate Assembly Upgrades: More Fragments, Faster Assembly, and Higher Fidelity

    Type
    Blog Post
    Published
    Oct. 11, 2018, 12:30 p.m.
    ...Golden Gate Assembly is commonly used to assemble 2–10 DNA fragments in a single “one-pot” reaction to...the transformants onto the selection plate. Figure 2 shows representative transformation plates obtained...fidelity studies conducted by Potapov et al. at NEB (1, 2). While T4 DNA Ligase, the mainstay of most biotechnological... (percent correct) Calculated colony totals Per 2 μl assembly reaction Per full assembly reaction** ...calculated yields from entire outgrowth built from 2 µl of the assembly reaction, and from the entire assembly...fidelity and bias profiling." bioRxiv (2018): 322297. 2. Potapov, Vladimir, et al. "A single-molecule sequencing...indeed possible, with correct, in-frame assembly proceeding in 99% of 12-fragment assemblies and over 90%...
  19. Viral Vectors 101: Integrase-Deficient Lentiviral Vectors

    Type
    Blog Post
    Published
    May 13, 2025, 1:15 p.m.
    ...joining (see Figure 2).  Figure 2: Schematic representation of integration process and episomal forms...due to insertional mutagenesis (Howe et al., 2008). 2. Transient expression of transgenes/shRNAs If you ...vectors: progress and applications. Gene Therapy, 17(2), 150–157. https://doi.org/10.1038/gt.2009.135. PubMed...efficiently during infection. Journal of Virology, 70(2), 721–728. https://doi.org/10.1128/JVI.70.2.721-728.1996...without the need for time-consuming purification processes, and are powerful, due to their ability to integrate...three separate enzymes that are proteolytically processed from the larger protein: PR (protease), RT (reverse...delivered to cells, the viral life cycle initially proceeds as usual. Reverse transcription of the transgene...
  20. Minigenomes - a Safe Way to Study Dangerous Viruses Like the Ebola Virus

    Type
    Blog Post
    Published
    March 17, 2016, 2:30 p.m.
    ...study aspects of the EBOV replication cycle under BSL-2 conditions (4). What is a minigenome?   The EBOV ...transcription by the EBOV polymerase (reviewed in 2, 5). The minigenome is capable of being replicated...nonsegmented negative sense RNA viruses (reviewed in 2, 3). Other important components of the Zaire ebola...as it would for a full-length viral genome (Figure 2). While it is technically possible to encode all four...500 ng NP, 500 ng VP35, 100 ng VP30, 100 ng L, and 2 μg minigenome plasmid per well (in a 6 well plate ...PubMed PMID: 9847328. PubMed Central PMCID: PMC103829. 2. Conzelmann, K. K. "Reverse genetics of mononegavirales...systems allow researchers to investigate viral processes in extreme detail. The mechanism of a particular...
  21. Grad School Advice Part 1: Picking a Lab and a Project

    Type
    Blog Post
    Published
    Sept. 1, 2016, 2:30 p.m.
    ...Introduction from Tyler 1:13 - 2:02 : Niroshi and Ben introduce themselves 2:03 - 3:22 : How did you end ...things get tough in the dreaded third year. Find Part 2 Here! We'd like to thank Niroshi and Ben for taking...Future of Research Looks to Improve the Research Process  Browse our Career Posts Resources on Addgene....
  22. Plasmids 101: Restriction Cloning

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    Blog Post
    Published
    Feb. 18, 2016, 3:42 p.m.
    ... used. Follow the manufacturer’s instructions.   2. Isolate Your Insert and Vector by Gel Purification...DNA concentration alone. One method is to conduct 2 ligations for each plasmid you are trying to create...containing the ligation mixture with backbone alone; 2. Transformation containing ligation mixture with insert...colonies than the vector + insert plate (unsuccessful 2), or roughly equivalent numbers of colonies on each... or equivalent to backbone + insert, unsuccessful 2 and 3 above), you can try ligating the recipient plasmid....   Overview of the restriction cloning process. Both the plasmid (blue, backbone) and the DNA ... beginning the restriction digest and ligation process, you should carefully choose your backbone and ...
  23. IBEX Knowledge-Base: A Data Resource for Multiplex Tissue Imaging

    Type
    Blog Post
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    June 8, 2023, 1:15 p.m.
    ...imaging of diverse tissues. Nature Protocols, 17(2), Article 2. https://doi.org/10.1038/s41596-021-00644-9 ...directly from the Zenodo dataset.     Figure 2: Screenshot showing reagent entries with associated...Knowledge-Base, seeking to create an iterative process that is constantly becoming better, with more data...spatial analysis of cells in complex tissues. Proceedings of the National Academy of Sciences, 117(52),...
  24. Antibodies 101: Chimeric Antibodies

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    Blog Post
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    April 25, 2023, 1:15 p.m.
    ...use 2 different secondaries for your antibody pair and visualize both targets in parallel (Fig. 2). For...successfully visualize both proteins.     Figure 2: Two primary antibodies with the same isotype can ...    Figure 1: In the isotype conversion process the variable regions of a parental antibody (blue...isotype (purple, mouse). Depending on the cloning process, all constant regions, just the heavy chain constant...isotype to that of a different group (Fig. 1). This process, called isotope conversion, gives users the flexibility...addition to increasing multiplexing capabilities this process is frequently used to reduce immunogenicity and...therapeutic potential of antibody medicines. In this process, antibodies derived from non-human species like...
  25. Fluorescent Proteins 101: Photoactivatable Fluorescent Proteins

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    Blog Post
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    April 25, 2017, 2:30 p.m.
    ...fluorescent state make them useful for 2-color imaging with green PA-FPs. Table 2: Properties of Selected Reversible... conventional FP imaging. PA-FPs are divided into 2 main categories - those with irreversible and reversible... forms of the chromophore which contribute to the 2 peaks of wtGFP’s excitation spectrum- a major 397 ... / N99K / S148L / I165V / Q167P / L169V / I203R) (2) and PA-mRFP1(S146H / I161V / I197H) (3) were derived...with two distinct wavelengths of light (see Table 2). The best known reversible PA-FP is the naturally... above background. The majority of PA-FPs come in 2 flavours- monomeric and tetrameric. Tetrameric PA-...most PA-FPs, but, in 2015, the Looger Lab designed 2 variants of EosFP that can withstand these conditions...
  26. CRISPR-based Genome Editing Systems For Editing in E. coli

    Type
    Blog Post
    Published
    April 13, 2021, 1:15 p.m.
    ...plasmids are cured from the cell. Steps 1-1 and 1-2 can be done simultaneously. Image from Li et al., ...1) replaced the promoter of gRNA-pMB1 with PrhaB, 2) changed the replicon of pCas into a non-temperature-sensitive... pEcCas/pEcgRNA system in 4 E. coli K-12 strains, 2 E. coli B strains, 1 E. coli W strain, and 1 Tatumella...MUCICAT better, it is faster. Using MUCICAT only needs 2 newly constructed plasmids (pDonor and pQCascade) ...rounds of transformation in 30 days. Figure 2: (A) MUCICAT plasmids for multicopy integration. (...pTargetF system.   Figure 1: The editing process begins with the addition of the sgRNA sequence ...curing, providing users with a complete editing process. The MUCICAT system While the above systems are...
  27. Tips for a 1st time AAV user (by a Rookie AAV user)

    Type
    Blog Post
    Published
    Oct. 23, 2018, 11:49 a.m.
    ...plasmid. This whole process takes ~3 hours to complete: 1 hours hands-on time and 2 hours for the qPCR ...then packaged into AAV’s protein shell, or capsid; 2) the pHelper plasmid which expresses adenovirus genes...quantification of adeno-associated virus serotype 2-derived inverted terminal repeat sequences. Human ...therapy methods, 23 1, 18-28. PubMed PMID: 22428977. 2. Choi, V.W., Asokan, A., Haberman, R.A., & Samulski...host’s polymerase, but requires Rep proteins to process a double-stranded intermediate into the single-...media are harvested and purified. In total, this process takes 4-7 days, not counting the time needed to...iodixanol and concentrate the purified virus. This process can be completed in one long day, or the virus ...
  28. Simplify Cloning with in vivo Assembly

    Type
    Blog Post
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    Oct. 18, 2018, 12:37 p.m.
    ...pathway to allow any cloning procedure to be performed using a simple two-step, 2 hr protocol prior to transformation...Primer design Using specific primer design (Figure 2), IVA cloning can be used to perform any plasmid modification... for each type of modification is shown in Figure 2, and is discussed in more detail below. The main requirement...Biotechniques 10.1 (1991): 62-66. PubMed PMID: 2003926. 2. Bubeck, Peter, Monica Winkler, and Wilfried Bautsch...often, it is also a bottleneck in the experimental process. The majority of current cloning techniques involve...be immediately adopted by any laboratory. All procedures are performed using the same three step protocol... greater homology, so performing more complex procedures can be aided by extending homologous sequences...
  29. Plasmids 101: How to Verify Your Plasmid Using a Restriction Digest Analysis

    Type
    Blog Post
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    Aug. 28, 2014, 3:34 p.m.
    .... Diagnostic restriction digests are comprised of 2 separate steps: 1) incubating your DNA with restriction...which cleave the DNA molecules at specific sites and 2) running the reaction on an agarose gel to determine...including a 1.2 kb insert. The plasmid was digested with 2 unique enzymes (HindIII and BamHI) and run on an agarose...to serve as a reference band. The uncut DNA (lane 2) shows 3 possible plasmid conformations, with relaxed...verification is not just necessary but also an easy process. Please vist Addgene's resource for plasmid verification...
  30. Antibodies 101: ChIP

    Type
    Blog Post
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    March 10, 2022, 3:25 p.m.
    ...to (1) run a DNA gel to confirm fragment size and (2)  incubate with RNAse and Proteinase K to purify the...proteins of interest to any DNA they were bound to (2) fragmented the DNA (3) used antibodies to specifically...adjustments, to get everything just right!  Fig. 2: Goldilocks is actually celebrating a successful ChIP...the ChIP process and not the upsteam sample collection process or the downstream analysis process. And ChIP...faint of heart!  The Process ChIP can be done for either tissues or cells. The process is very similar for...remain attached to the DNA throughout the sample processing and therefore will require crosslinking, which...done by cutting the tissue sample up and then processing with a homogenizer, but bone or especially fibrous...
  31. Grad School Advice Part 2: Building Community

    Type
    Blog Post
    Published
    Oct. 6, 2016, 2:30 p.m.
    ...these topics. Listen to Part 1 Here Listen to Part 2 here! Time : Topic 0:00 - 0:50 : Intro 0:51 - 3:08...Improvements that can be made to the grad school process 22:41 - END : Niroshi and Ben's favorite advice...Future of Research Looks to Improve the Research Process  Browse our Career Posts Resources on Addgene....
  32. A Primer on Optogenetics: Introduction and Opsin Delivery

    Type
    Blog Post
    Published
    Sept. 10, 2015, 2:30 p.m.
    ...commonly used in optogenetics: 1) electrophysiology and 2) behavioral experiments. I’m not an electrophysiologist...choice in the brain region you wish to stimulate 2) Fabrication and implantation of the optical fiber...thoroughly elsewhere (here and here for instance) [2], [3]. Karl Deisseroth of Stanford University , one...reviews for a discussion of the different variants [1, 2, 4]. And, of course, the best way to learn about the...monitor expression at various time points (e.g. every 1-2 weeks over 8 weeks) in order to determine the optimal...(4):251-66. doi: 10.1038/nrn3171. PMID: 22430017. 2. Fenno L, et al. The development and application of...analysis of microbial opsins. Nature methods. 2012;9(2):159-72. doi: 10.1038/nmeth.1808. PMID: 22179551; ...
  33. Viral Vectors 101: AAV Variables That Matter

    Type
    Blog Post
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    June 1, 2023, 1:15 p.m.
    ...testing your AAV.  Figure 2: Comparison of AAV serotypes 1, 2, 5, 6, 8, and 9 in two different ...selection process. Factors to think about are (1) your experimental conditions and measurements; (2) the cells... Tropism and Axonal Transport of AAV Serotypes 1, 2, 5, 6, 8 and 9 in the Mouse Brain. PLOS ONE, 8(9),... Comparison of four promoters. Gene Therapy, 28(1–2), 56–74. https://doi.org/10.1038/s41434-020-0169-1...analyses of adeno-associated viral vector serotypes 1, 2, 5, 8 and 9 in marmoset, mouse and macaque cerebral...will allow you to efficiently move through this process.  Many other factors can also affect your AAV experiments...
  34. Viral Vectors 101: What is a Virus (and a Viral Vector)?

    Type
    Blog Post
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    Aug. 18, 2023, 4:15 p.m.
    ...developed around how they replicate (Figure 2). Figure 2: Baltimore replication classes. Image credit...safer viral vectors that can be used in BSL-1 or BSL-2 labs. Viral vectors are viruses that have been genetically...and eukaryotes, which use a binary replication process whereby one cell copies itself and “splits” into...” genome with genes central to the replication process removed. This means the vector can deliver a genetic...
  35. CRISPR 101: Cytosine Transversion Editors

    Type
    Blog Post
    Published
    March 25, 2025, 1:15 p.m.
    ...Nature Cell Biology, 26(2), 294–304. https://doi.org/10.1038/s41556-023-01342-2 Koblan, L. W., Arbab, M...order to bind DNA, Cas9 requires (1) a guide RNA, (2) a complementary DNA sequence, and (3) a protospacer-adjacent...region of separate strands called an R-loop (Figure 2). This allows the guide RNA to base pair with the ...accessible on the outside of the enzyme. Figure 2: CRISPR R-loop. Created with BioRender.com. Base...), 35–40. https://doi.org/10.1038/s41587-020-0592-2 Additional Resources on the Addgene blog CRISPR 101...inhibitor of base excision repair (BER), the cellular process that catches mutated U’s in DNA and ideally converts... In this case, the team suspected that the BER process was excising the incorrect U base, creating an ...
  36. RNA Interference in Plant Biology: New Tools for an Old Favorite

    Type
    Blog Post
    Published
    Oct. 27, 2020, 1:15 p.m.
    ... analogs such as 2-fluoroadenine (2-FA), organisms with functional APT will convert 2-FA to cytotoxic ...selection of plants undergoing RNAi, and LIIbeta F 1-2 RNAi, which allows assembly of intron-spliced hpRNAs...nucleotides, resulting in death. In the presence of 2-FA, potent gene silencing of APT is required for survival...block of our understanding of complex biological processes. Many tools exist to perturb biological function... interference (RNAi) is a conserved eukaryotic process where approximately 20-30 nucleotides of double-stranded...formation of a hairpin RNA structure, resulting in processing by the endogenous RNAi machinery. Alternatively... engineered to created artificial miRNAs. The processed miRNA or siRNAs then silence the target gene(s...
  37. 22 Hot Plasmid Technologies from 2014

    Type
    Blog Post
    Published
    Jan. 6, 2015, 5:21 p.m.
    ...Currently available from the Kim lab are 2 presynaptic and 2 postsynaptic targeting mGRASP plasmids. Additionally... cells were pulsed with 2µg/ml of Doxycycline for 2 hours, and imaged on the Keyence BZ-9000 fluorescence...work! Robinson et al., Dev Cell 2010 Feb 16;18(2):324-31. Cheeseman et al., J Cell Sci 2013 May 1...promotes the formation of an isopeptide bond between 2 peptide tags, SpyTag and KTag. The group demonstrated... of three sets of cloning vectors (Level 0, 1, or 2) which can be utilized in three successive assembly...1 modules can be similarly assembled into a Level 2 vector, thus forming a functional genetic circuit....circuit. Flexibility has been built into the Level 2 vectors to allow for additional iterations of Level 1 assembly...
  38. CRISPR-mediated Plant Base Editors

    Type
    Blog Post
    Published
    Jan. 3, 2019, 1:35 p.m.
    ...satisfactorily accepts DNA as its substrate (see figure 2).          The artificially evolved adenosine deaminase...editing platforms for plant systems.  Figure 2: Plant base editor platforms and their molecular components...available for plant systems. Target-AID based (CBE-2)-  and rAPOBEC based (CBE-1)-  CBEs are successful...based CBEs are known to deaminate cytosine placed in 2-6 bp and 4-8 bp, respectively, of the protospacer....PMID: 27096365. PubMed Central PMCID: PMC4873371.  2. Nishida, Keiji, et al. "Targeted nucleotide editing...capability with the endogenous tRNA-processing system." Proceedings of the National Academy of Sciences...
  39. A Needle in a Base-Stack: Cas9 Structural Biology

    Type
    Blog Post
    Published
    June 4, 2024, 1:15 p.m.
    ...Cas9 from Streptococcus pyogenes.   Figure 2:  Crystal structure of S. pyogenes Cas9 in the apo...NUC and REC lobes laying open like a book (Figure 2). The portion of the CTD that recognizes the PAM is...it doesn’t appear in the crystal structure (Figure 2) at all. When this crucial recognition region is disordered...regions, so crystal structures like those in Figures 2 and 3 don’t show these regions, even if they are present...itself at the bottom of the image. Stem loops 1 and 2 extend horizontally across both lobes. The guide RNA...is required for Cas9 nuclease function. Stem loops 2 and 3 are not strictly necessary for in vitro cleavage...open conformation, but highly flexible, as in Figure 2. The guide RNA is bound primarily by the REC lobe,...
  40. No Llamas Required - Synthetic Nanobodies Against Membrane Proteins

    Type
    Blog Post
    Published
    June 18, 2020, 1:15 p.m.
    ...optimal sybody candidates. Figure 2: Outline of the process for selection of sybodies against membrane...identify and isolate sybodies targeting the SARS-CoV-2 Receptor Binding Domain found on the membrane-bound...Generation Toolbox kit. Find the Seeger lab's SARS-CoV-2 sybodies! References Geertsma ER (2013) FX Cloning...2020) Synthetic nanobodies targeting the SARS-CoV-2 receptor-binding domain. BioRxiv.  https://doi.org...sybody), ribosome, and mRNA. During the screening process, displayed sybodies that bind to the biotinylated...
  41. Tetbow: Bright Multicolor Labeling for Neuronal Tracing

    Type
    Blog Post
    Published
    Jan. 24, 2019, 2:24 p.m.
    ...possible when each of the XFP genes is introduced at ~2 copies per cell per color, following a Poisson distribution...(prepared with Addgene #104110 - #104112) (Figure 2). We’ve also created constructs with containing chemical...AAV titer - The XFP genes have to be introduced at ~2 copies per cell per color to achieve the highest color...samples and visualize. For more details on this procedure, find the protocol here.   Tips and troubleshooting...Ultrafast tissue staining with chemical tags." Proceedings of the National Academy of Sciences111.36 (2014...
  42. Optimizing Donor DNA for Enhanced CRISPR Genome Editing

    Type
    Blog Post
    Published
    March 24, 2016, 2:30 p.m.
    ...mechanism of action are presented in Figure 2. Figure 2: Single-stranded donor DNA interaction with...Nature biotechnology (2016). PubMed PMID: 26789497.  2. Lin, Steven, et al. "Enhanced homology-directed human... a biological process in detail often suggests new strategies to manipulate that process. We began our...
  43. DNA Purification Without a Kit

    Type
    Blog Post
    Published
    Feb. 11, 2020, 2:15 p.m.
    ...agarose. Proceedings of the National Academy of Sciences of the United States of America, 76 2, 615-9 ....alkaline lysis plasmid miniprep Starting material: 2 mL bacterial culture Product: plasmid DNA This kit-free...protocol: 1) it solubilizes both DNA and agarose, and 2) it helps DNA stick to the glass. After binding DNA... had a similar level of sensitivity. Figure 2: Steps to purify DNA using a cellulose dipstick. Image...and without degradation during the extraction procedure. Additionally, purified DNA was free of agarose...
  44. Plasmids 101: Gateway Cloning

    Type
    Blog Post
    Published
    Jan. 12, 2017, 3:30 p.m.
    ...is excised from the donor vector.   Figure 2: The Gateway system adopts phage integration into ...our website to search for your favorite gene! STEP 2: Generate an Expression Clone When making the expression...expression construct in only 1 day, as opposed to 2+ days with traditional restriction and ligation cloning...Clon Transgen 4:138. doi:10.4172/2168-9849.1000138 2. Hartley JL. Use of the Gateway System for Protein...using Gateway technology To better understand the process, we’ll walk through an example experiment where...directly into destination vectors. The cloning process is simple -  no restriction, ligation or gel purification...
  45. Antibodies 101: Flow Cytometry

    Type
    Blog Post
    Published
    July 20, 2021, 1:15 p.m.
    ... a population in a procedure termed fluorescence activated cell sorting or FACS (2). By analyzing single...expression. A routine flow cytometry experiment uses 2 or 3 different fluorescent colors each measuring a...distinct populations on a FSC versus SSC plot (Figure 2).  A user can then “gate” around the specific population...cell and T cell into distinct populations (Figure 2). An immunologist who studies B cells, might then ... B cells, plasma cells or others.   Figure 2: Due to differences in their size and complexity, ...forces the cells to line up in single file in a process termed hydrodynamic focusing. This allows each ...factors including sample preparation, staining procedures, and controls. To prevent instrument clogs, ensure...
  46. Troubleshooting Your Plasmid Cloning Experiment

    Type
    Blog Post
    Published
    Sept. 24, 2019, 12:55 p.m.
    ... working with is correct. It's also best to use 1-2 ug of the vector for digestion. PCR Design primers...plasmid; a starting point could be a molar ratio of 1:2 (plasmid:insert), but this parameter has to be optimized...colonies (5-10) and grow them in a small culture volume (2 or 3 ml) containing the corresponding antibiotic, ...scientist at Addgene. Cloning can be quite an arduous process. The PCR could fail to produce a product, the transformation...can go wrong! With all the steps in the cloning process, there are also many ways to troubleshoot the cloning...Addgene. In the lab he develops new assays and processes. Outside the lab, he enjoy the outdoor in all ...
  47. Plasmids 101: FLEx Vectors

    Type
    Blog Post
    Published
    April 28, 2016, 2:30 p.m.
    ...conditional knock-in cassette. As shown in Figure 2, the cassette should contain a reporter DNA sequence...a targeted neuronal population.    Figure 2 (modified from Schnutgen et al. Nat Biotech 2003):...cellular level in the mouse. 2003 PubMed PMID: 12665802. 2. Branda, CS and Dymecki, SM. Talking about a Revolution... SM. 2008. A FLEX switch targets Channelrhodopsin-2 to multiple cell types for imaging and long-range ...SSR of choice is introduced, recombination can proceed either by first utilizing the loxP sites or the...
  48. Controlling for Off-target Effects with a New Genome-wide CRISPR Screen Design

    Type
    Blog Post
    Published
    Sept. 13, 2018, 1:55 p.m.
    ...guide expression and dsDNA breaks. Figure 2: Non-targeting vs. safe-targeting guides. The genome-wide...target all protein-coding genes present in the genome; 2) non-targeting guides (red), which target no sequence...guides that had zero mismatch off-targets. Guides with 2-bp mismatch off-targets were only toxic if they had...tolerated than mismatches more distal to the PAM, and 2) guides with high GC content have greater off-target...PMID: 28474669. Pubmed Central PMCID: PMC5424143. 2. Tsai, Shengdar Q., et al. "GUIDE-seq enables genome-wide...for identifying genes involved in a biological process. These screens provide an alternative to genome-wide...
  49. 5 Steps to Writing Grant Proposals for Grad Students

    Type
    Blog Post
    Published
    Feb. 11, 2014, 12:13 p.m.
    ...require application submission in-house approximately 2 weeks before the RFA due date in order for the administrative...deliverables to the aims requested in the call. Step 2: Develop a research plan Most grant applications ...proposal typically lists the deliverables, explains 1-2 potential pitfalls of the intended protocol, and offers...want to mentor you during the grant application process. When my PhD advisor first asked me to write a ...PI asks for assistance in the grant application process, she has faith in you! Additionally, keep in mind...motivating research will help you understand the process and continue to improve your grant writing skills...Still want more information on the application process? What types of writing feedback do you find most...
  50. Fluorescent Proteins 101: Introduction to FRET

    Type
    Blog Post
    Published
    June 27, 2017, 1:03 p.m.
    ... fluorophore excitation by absorption of a photon 2. Energy transfer from the excited donor directly to...PMID: 24194740. PubMed Central PMCID: PMC3810607. 2. Bajar, Bryce T., et al. "A Guide to Fluorescent Protein...PubMed PMID: 10500161. PubMed Central PMCID: PMC18018. 2. Miyawaki, Atsushi, et al. "Fluorescent indicators...orientation of the FRET pair. Since many biological processes occur within the typical FRET range, FRET efficiency...fluorophore on the same protein and are useful when a process affects the conformation of the probe. More on ...answer sophisticated questions about cellular processes. Currently, FRET experiments can probe protein-protein... activity of small molecules, detect cellular processes and signaling cascades, quantify mechanical tension...
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