We narrowed to 587 results for: cel.2;
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TypeBlog Post... York: Crown Publishers, 2010. 2. Gold, Michael. "A conspiracy of cells." State University of New York...quality work in cell culture. The problems with cell lines Simply put, the majority of cell line problems...HeLa cells, the first immortalized human cell line. He proved this by examining whether the cell lines...Cancer Cells, Marker-independent identification of glioma-initiating cells. The International Cell Line ...working cell bank has been made by a research institution (an excellent practice), or maybe cells have been...Animal Cell Culture Guide Thermofisher Guidelines for Maintaining Cultured Cells Invitrogen Cell Culture... Outreach Scientist Nick Amiss. Cell culture in the present day Cell culture is a widespread tool used...
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Typing CRISPR Systems
TypeBlog Post... 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...). Class 2 CRISPR/Cas: an expanding biotechnology toolbox for and beyond genome editing. Cell & Bioscience...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... -
Plasmids 101: Knockout/Knock-In Plasmids
TypeBlog Post...the addition of Cre recombinase (Figure 2). Figure 2: A knockout targeting vector designed to...construct. For recombination to occur in a cell, a minimum of 2 kb of sequence homology is required, but...Deliver your construct to your target cells. After recombination, exon 2 of the targeted gene will be removed... through an experiment designed to knock out exon 2 of a given gene. Figure 1: A knockout targeting...the GFP/NeoR cassette is inserted in place of exon 2. Thus, the targeted gene is disrupted (knocked out...recombination event will remove NeoR only and leave exon 2 floxed, as seen in line 4 of Figure 4. Since the loxP...recombined cells. Recombination is a rare event, so you must select as opposed to screen for cells where recombination... -
Antibody Production
TypeCollection...for shipping stability by incubating at 37 °C for 2 weeks, freezing at -80 °C, thawing on ice, and then...mammalian expression vectors, human embryonic kidney cells are transfected with the plasmid(s) encoding the.... This buffer is not compatible for use in live cells and will interfere with conjugation. For applications...antigen is first transiently expressed in mammalian cells. To learn which specific QC experiments were performed...email [email protected] . Immunocytochemistry (ICC) Cells are fixed and labeled with the antibody and a species-specific...Western Blotting (WB) Proteins are extracted from cells, separated by SDS-PAGE, transferred to a membrane... -
Addgene's Top Blog Posts from 2020
TypeBlog Post...CRISPR to detect SARS-CoV-2, including many with plasmids deposited at Addgene! 2. DNA Purification Without...detection methods, synthetic nanobodies, SARS-CoV-2 protein expression, and more. We also highlighted ...empty backbones, fluorescent protein tags, SARS-CoV-2 plasmids, etc. It is our hope that by providing cloning...RNA and extracting RNA without a kit. 3. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas by ...multiple plasmids in one cell, it might be that you can't stably maintain them in the cell. This blog post features... -
Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering
TypeBlog Post...generate 2 possible products: 1) a partially dsDNA duplex with single-stranded 3’ overhangs or 2) if the...but these cells are prone to mutations and will have more unintended changes to their genomes. 2) Designing...recombineering system has three components (Figure 1): 1) Exo, 2) Beta, and 3) Gam. All three are required for recombineering...generic lambda red recombineering experiment (Figure 2). In the following sections, key steps that differ...confirmation of recombinant clones. Figure 2: Overview of using Lambda Red recombineering system...pairs of homology to the targeted insert site (Figure 2, top). These primers are typically ~70 nucleotides...bacteria that has key MMR proteins knocked out or 2) specially design ssDNA oligos to avoid MMR: 1) E.... -
Tips for a 1st Time CRISPR User (by a 1st Time CRISPR User)
TypeBlog Post... Figure 2: Cas9 expression in monoclonal cell lines generated from A549 cells transduced with ... a range of reasonable MOIs. 2. Create a monoclonal Cas9-expression cell line. Especially if you’re doing...(Figure 2) and I was surprised at how variable Cas9-expression was across the different cells (Figure ...Overview: By Western blotting (Figure 2, pool), I knew the cells expressed Cas9, but I didn’t know what...knockouts and knockins in human somatic cells. Nature Protocols 2007; 2(11): 2734-46. PubMed PMID: 18007609...despite having active Cas9 (see tip 2). Pro-Tips 1. To quantify Cas9 activity using this assay, you really...Western blotting against GFP expression, but I didn’t. 2. In the original publication they see GFP expression... -
Deisseroth INTRSECT Collection
TypeCollection...dual-transgenic recombinase-expressing mouse lines 2–9 and combinations of transgenic recombinase-expressing...delivering additional recombinases 10–14 . Figure 2: INTRSECT works by inserting short, intronic sequences...well-defined cellular sub-populations has generally been limited to single-component cellular definitions...to enable three-feature cell targeting. C) Example of viral targeting of cells expressing Cre AND Flp,...parameters. Figure 1: Examples of intersectional cell population definitions using recombinases. A) Cre...adeno-associated virus (AAV)-borne payloads to be expressed in cells based on a doubly-specified combination of genetic...multiple recombinase-expression strategies to define cellular sub-populations of interest, including dual-transgenic... -
Antibodies 101: Fab Fragments
TypeBlog Post...fragments that retain antigen binding (Figure 2): F(ab')2 - These fragments are produced by proteolytic... multiplexed super-resolution microscopy. Cell Rep Methods 2(10):100301. https://doi.org/10.1016/j.crmeth...fragments are produced by mild reduction of F(ab')2 fragments, which reduces the hinge region disulfide...Variable (scFv). Size: ~25 kDa. Figure 2: Comparison between a full IgG antibody and common...advantages, though with some caveats. First off, F(ab’)2 fragments are bivalent, so may have higher avidity...or Fab fragments. Higher avidity means that F(ab’)2 fragments may have overall stronger interaction with...Clinical Prospects of Antibody Fragments. Antibodies 8(2):28. https://doi.org/10.3390/antib8020028 Wessel... -
Viral Vectors 101: Producing Your rAAV
TypeBlog Post...digital PCR. Human Gene Therapy Methods, 25(2), Article 2. https://doi.org/10.1089/hgtb.2013.131 Lock,... and keep the cells happy. Harvesting virus Once you have transfected your cells, wait 2–5 days and then...quantification of adeno-associated virus serotype 2-derived inverted terminal repeat sequences. Human ..., R., & Kleinschmidt, J. (1999). Titration of AAV-2 particles via a novel capsid ELISA: Packaging of genomes... genomes can limit production of recombinant AAV-2. Gene Therapy, 6(7), Article 7. https://doi.org/10.1038...Characterization of a recombinant adeno-associated virus type 2 Reference Standard Material. Human Gene Therapy, 21...however, you’ve collected the producer cells, you’ll need to lyse the cells to let the virions out. We recommend... -
Antibodies 101: Normalization and Loading Controls for Western Blots
TypeBlog Post...the resulting fraction is reported. Figure 2: Normalization with loading controls. Under each lane...control band is weaker in condition 1 than condition 2, the normalized values for the two conditions are ...opposite change in your loading control. Assumption #2: The loading control can be accurately quantified ...significantly lighter in “condition 1” than “condition 2.” By eye, the loading control appears about the same...) are smaller than the analogous green “condition 2” points by the exact same value. For the two solid...consider a different loading control. Assumption #2: The loading control can be accurately quantified ...factors we’ve covered in our previous blog posts (1, 2) on western blotting. If the abundance of your POI... -
Plasmid Preps: Different Purity, Different Quantities, Different Uses
TypeBlog Post...electrocompetent cells is minimal (picogram range). It can be extracted from small bacterial cultures (i.e. 2-3 ml...ratios measured at 260 and 280 nm should fall ~1.8 - 2 and give scientists an indication of purity versus...contaminants. The 260 and 230 nm ratios should fall ~2 - 2.2, and provide an indication of purity versus ...hydrochloride used during plasmid extraction. Figure 2: Use cloning grade DNA for direct cloning of your ...lipopolysaccharide of the cell wall of Gram negative bacteria like E. coli that affects tissue culture cell line viability...introduces transformation grade plasmids into a bacterial cell. Transformation grade DNA Transformation is ...Figure 3: Need to introduce plasmids into mammalian cells? Use transfection grade DNA. Transfection is ... -
Hot Plasmids - October 2022
TypeBlog Post...GEVIs (called ASAP 1 and 2), they found an indicator that is optimized for 2-photon imaging of voltages...challenges in 2-photon in-vivo imaging of voltage fluctuations. Image credit: Liu Z, et al. Cell. 2022. ...suitable for in vivo optogenetic use. Fig. 2: A) HcKCR1 is highly selective for K+ over other Na...slice of HcKCR1-EYFP and tdTomato expressed layer 2/3 neurons in mouse. C) Action potential frequencies...two-photon microscopy. Cell, 18, 3408 - 3425.e29. (2022). https://doi.org/10.1016/j.cell.2022.07.013. ...specific for human c-myc proto-oncogene product. Mol Cell Biol. Dec;5(12):3610-6.(1985). doi: 10.1128/mcb.5.12.3610... -
Rosella: A Fluorescent pH-Biosensor for Studying Autophagy
TypeBlog Post...Table 2 for more details on the effect of pH on the fluorescent properties of Rosella. Table 2: Effect...in yeast. Autophagy,4(2), 205-213. doi:10.4161/auto.5331. PubMed PMID: 18094608 2. Sargsyan, A., Cai, J...environment like the vacuole or lysosome. See Table 2 for a summary of what color fluorescence Rosella emits...fluorescence accumulates in the vacuole. See Figure 2 for an example of what fluorescence looks like for... Mammalian Autophagy Research. Cell,140(3), 313-326. doi:10.1016/j.cell.2010.01.028. PubMed PMID: 20144757...analyzing autophagy of cytosol and organelles in yeast cells. Autophagy (Greek for “self-eating”) is induced ...radio-labeled long-lived proteins as a proxy for autophagy. Cells are cultured with isotope-labeled amino acids for... -
Plasmids 101: Secondary Nanobody Toolbox
TypeBlog Post...Journal of Cell Biology. PubMed PMID: 29263082 Find plasmids from this publication at Addgene. 2. Bates,...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... -
The Materials Science of Optogenetics Experiments
TypeBlog Post...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...Pharmacology and Optogenetics. Cell 162.3 (2015): 662-674. doi: 10.1016/j.cell.2015.06.058. Pubmed PMID: 26189679... -
Multiplexed Capture of Promoter-enhancer 3D Chromatin Structures Using CRISPR
TypeBlog Post...eGFP tag, and 2) gRNAs Number of loci targeted One Many Sample type(s) Cell lines Cell lines, primary...Expression system Stable cell line expressing 1) FLAG-biotin-tagged dCas9, 2) BirA, and 3) one or more...Originally published Dec 7, 2017 and updated Jul 2, 2020. Promoters may be the star of gene regulation...sequence targeted in the experiment. Figure 2: Comparing CAPTURE and CAPTURE 2.0. Original...identified and the level of on-target enrichment. 2. Determining the spatial and hierarchical organization...Cytogenetics, 11. https://doi.org/10.1186/s13039-018-0368-2 Liu X, Zhang Y, Chen Y, Li M, Zhou F, Li K, Cao H... of cells (~5x107). Together, these two requirements prevent the use of CAPTURE with primary cells or ... -
CRISPR Between the Genes: How to Experiment with Enhancers and Epigenomics
TypeBlog Post...for the 2+ million DHS sites. See below for further details. DNA is a 3D Fractal Figure 2: DNA compaction... we identified in step 2. The result is a heterogenous population of stem cells, usually housed in a single...: 1. Find Enhancers that have NANOG binding sites 2. Design a CRISPR screen to target and disrupt the ...NANOG enhancers 3. CRISPR out the enhancers from step 2. See which ESCs die or differentiate Step 3 reveals...expression for NANOG enhancers, we’re ready for step 2: design a CRISPR screen to disrupt these enhancers... for stem cells, or metastasized tumor cells, or alzheimers-affected neurons, or [your cell line of interest...critical to stem cell survival. Knowing which genes influence the survival of our cell culture is the foundation... -
Viral Vectors 101: The Retroviral Lifecycle
TypeBlog Post...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...synthesized inside of what is called the “target cell” (or host cell) by the viral protein reverse transcriptase... -
Minigenomes - a Safe Way to Study Dangerous Viruses Like the Ebola Virus
TypeBlog Post...reviewed in 2, 5). The minigenome is capable of being replicated and transcribed in the cell when the appropriate...study aspects of the EBOV replication cycle under BSL-2 conditions (4). What is a minigenome? The EBOV ...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...choose cell lines that are highly transfectable. The amounts of each plasmid transfected into cells are ... -
Cpf1: A New Tool for CRISPR Genome Editing
TypeBlog Post...single RNA-guided endonuclease of a class 2 CRISPR-Cas system." Cell (2015). PubMed PMID: 26422227. Find ...Cpf1 is a single RNA-guided endonuclease of a class 2 CRISPR-Cas system. Figure from Zetsche et al., 2015...2015. How was Cpf1 found and tested? Class 2 CRISPR systems, including the type II Cas9-based system...employed by class 1 systems. A putative new class 2 nuclease, Cpf1 (CRISPR from Prevotella and Francisella... the 3’ end of the target sequence. Figure 2: Effects of (A) double and (B) single base pair gRNA-target...Find plasmids from this publication at Addgene. 2. Zetsche, Bernd, et al. "Multiplex Gene Editing by CRISPR–Cpf1...orthologs that display cleavage activity in mammalian cells. Like Cas9 nucleases, Cpf1 family members contain... -
Important Considerations When Using AAVs
TypeBlog Post...University of Manitoba due to their Biosafety Level-2 or 2+. Please Note: Despite the fact that AAVs themselves...Location (1): What tissue? Location (2): Where in the tissue/which cell type? Location (3): Traveling from...in very specific cell populations. Find Ready-to-Use Retrograde AAV Preps at Addgene 2) Comparison of genetically...long and stable expression (up to 9 months in mice [2]). Low Immune Response: Compared to other viral vectors...may be sufficient to overcome the transport issues. 2. Failure to plan (for storage) Is planning to fail...Therapy 15.10 (2007): 1740-1743. PubMed PMID: 17882145. 2. Zincarelli, Carmela, et al. "Analysis of AAV serotypes... tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain." PloS one 8.9 (... -
Fluorescent Proteins 101: Photoactivatable Fluorescent Proteins
TypeBlog Post...fluorescent state make them useful for 2-color imaging with green PA-FPs. Table 2: Properties of Selected Reversible...PA-FPs come in 2 flavours- monomeric and tetrameric. Tetrameric PA-FPS are better for whole cell imaging and... of proteins and cells." Science 297.5588 (2002): 1873-1877. PubMed PMID:12228718. 2.Subach, Fedor V.,... 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... -
Screening for Successful Genome Editing with Digital PCR
TypeBlog Post... (details in [2]) and can be used to quantify rates of mutation in a bulk or single cell-derived genomic...resulting from non-homologous end joining (NHEJ) (2-5), depending on your desired genome edit. Since exploitation... have been reported for mismatch nuclease assays (2, 6, 7). Ability to distinguish between mono-allelic...assays, in addition to testing their performance (2). Remember that although digital PCR is a great screening...PMID: 24509632. PubMed Central PMCID: PMC4063274. 2. Findlay, S. D., Vincent, K. M., Berman, J. R. & Postovit... successfully analyzed gDNA from a few thousand cells from single wells of a 96-well plate without prior... that they are easily able to distinguish single-cell derived samples with mono-allelic mutations versus... -
Finding nucleic acids with SHERLOCK and DETECTR
TypeBlog Post...Diverse Class 2 CRISPR-Cas Systems. Molecular Cell 60:385–397 . https://doi.org/10.1016/j.molcel.2015.10.008...Endonuclease of a Class 2 CRISPR-Cas System. Cell 163:759–771 . https://doi.org/10.1016/j.cell.2015.09.038 Additional... can be used to diagnose the presence of SARS-CoV-2 RNA, but inadequate access to reagents and equipment...named this system SHERLOCKv2 for SHERLOCK version 2. Here are some of the improvements: SHERLOCKv2 uses... a protocol for using SHERLOCK to detect SARS-CoV-2 RNA. The test is started using RNA purified from patient...recently adapted the DETECTR platform to detect SARS-CoV-2 using a lateral flow strip format. They published ...CY (2020) CRISPR–Cas12-based detection of SARS-CoV-2. Nature Biotechnology. https://doi.org/10.1038/s41587... -
Sleeping Beauty Awakens for Genome Engineering
TypeBlog Post... of 2 components: 1) an SB transposase, the enzyme required for catalysis of transposition; and 2) a transposon...stable transgenic cell lines. Biotechnol J. 2015 Feb 4. doi: 10.1002/biot.201400821. PubMed. 2. Mates L, et... gene (red) for expressing the transposase enzyme.2.) The transposase enzyme is expressed (red stars) ...to infect and replicate in host cells, but they are susceptible to cells’ defense mechanisms. The use of... transposon; the plasmid is then degraded by the cell.4.) The transposase creates a double strand break...improve its gene insertion efficiency in primary cells. In 2009, Zsuzsanna Izsvak’s lab screened many SB...tranposase variants for hyperactivity in mammalian cells. Their efforts resulted in a new and improved SB... -
CRISPRainbow and Genome Visualization
TypeBlog Post...Addgene. 2. Ma, Hanhui, et al. “Multicolor CRISPR labeling of chromosomal loci in human cells.” Proc. ...two genes over time, at a range of distances from 2-75 Mbp. Labeling multiple, intrachromosomal loci Building...successfully resolved loci with physical map distances of 2 and 75 Mbp, with the calculated fluorescent distances...established physical map. In comparing pairs of targets ~2 Mbp apart, they noticed that they could evaluate the...dCas9 supplied by a separate vector. Figure 2: CRISPRainbow generates 6 unique colors and a white...Genomic Loci in Living Human Cells by an Optimized CRISPR/Cas System.” Cell 155 (2013): 1379-1491. Pubmed...of 6 chromosome-specific loci in the U20S cancer cell line./ Each color represents a gRNA targeting a ... -
Plasmids 101: Modular Cloning
TypeBlog Post...TUs. Level 2: Assembly of multiple Level 1 TUs into multigene constructs. Figure 2: The three ...can be queried by testing any number in the Level 2 assembly. These pathways can require a lot of optimization... of multigene constructs. PLoS One. 2011 Feb 18;6(2):e16765. doi: 10.1371/journal.pone.0016765. Hahn,... (2020). https://doi.org/10.1186/s12870-020-02388-2 Resources on Addgene.org Addgene’s Modular Cloning...complex cellular behaviors requires making complex manipulations to cells. For example: in a cell there ... yield a cellular phenotype, translational output, etc., which can support a larger cellular engineering...TU, or even an individual part, will behave in a cell. For unpredictable cases, MoClo provides two answers... -
CRISPR 101: Multiplex Expression of gRNAs
TypeBlog Post...illustrated in the schematic below. Figure 2: gRNA target sequences (colored rectangles) are cloned... plasmids: This plasmid set allows you to express 2-4 gRNAs, with four being the ideal number. First you...the total number of gRNAs you wish to clone, from 2-7. For example, if you’re expressing 4 gRNAs, you’...gRNAs into spectinomycin-resistant plasmids pX330S-2 to pX330S-(last gRNA number). The 5’ most gRNA is ...Multiplexing Plasmids: These plasmids allow you to assemble 2-4 gRNAs through Golden Gate or Gibson Assembly. gRNAs...Multiplex Plasmids: These plasmids allow expression of 2-5 gRNAs in zebrafish. Custom destination vectors are...and a subsequent curing protocol that requires only 2-3 hours incubation. Kondo Lab multiplexed base editing... -
Multiplex Genome Editing with CRISPR-Cpf1
TypeBlog Post...expression and needing to work with a transfectable cell line. 2) They require larger expression vectors which...Single RNA-Guided Endonuclease of a Class 2 CRISPR-Cas System. Cell,163(3), 759-771. PubMed PMID: 26422227...are also larger than their Cpf1 counterparts. Table 2. Cas9 Multiplexing Options Multiplexing Method... Cpf1 expression vector. See the graph in figure 2 for a comparison of editing frequency resulting from...Biotechnology 35.1 (2016): 31-34. Pubmed PMID: 27918548. 2. Zetsche, B., Gootenberg, J., Abudayyeh, O., Slaymaker... of 4 crRNAs in vitro and when expressed in 293 cells. This allows for a single promoter to drive expression... were used. With transfection, 6.4% of HEK293T cells had edits at 4 of 4 targets when an array of 4 crRNAs... -
Antibodies 101: Designing Your First Flow Panel
TypeBlog Post...Table 2, Figure 5) for a hypothetical experiment in the lab. Let's say I am culturing HEK 293T cells in ... weak. Table 2: A simple flow panel to detect live, transduced, and CD45-expressing cells. Marker .... To understand why that is, let's look at Figure 2. The blue laser excites at a wavelength of 488 nm ... of PE's excitation spectrum (dotted line, Figure 2). The yellow/green laser, however, excites at 561 ... stronger — or brighter — signal. Figure 2: Excitation and emission spectra for PE. The excitation...efficiency (eGFP expression). The first item in Table 2 is a standard and should always be included—the live...from the other fluorophores to avoid bleeding and 2) BV421 is a very bright fluorophore, which makes it... -
Genome-wide Screening Using CRISPR
TypeBlog Post...plasmid, or a 2-plasmid system in which Cas9 must be delivered separately. Mutant cells are enriched ...diseases causing uncontrolled cell growth, such as cancer. Figure 2: The CRISPR library must be ...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?...CRISPR libraries is a multi-step process (see Fig. 2). In most cases, CRISPR libraries are provided at ...heterogeneous population of mutant cells, with each cell or set of cells containing a mutation in a different...fluorescence-based cell sorting and screened for a particular phenotype. For example, mutant cells can be used... -
A Primer on Optogenetics: Introduction and Opsin Delivery
TypeBlog Post...: PMC3337962. 8. Zhao S, et al. Cell type-specific channelrhodopsin-2 transgenic mice for optogenetic ...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... -
Luciferase Plasmid Collection
TypeCollection...and Venus fluorophore to Troponin C Ca 2+ binding domain. Nano-lanterns , Enhanced Nano-lanterns , and...transfection Feng Zhang 21471 pLenti PGK V5-LUC Neo (w623-2) Firefly PGK Lentiviral expression of firefly luciferase...Expression of firefly luciferase from a cell-free mammalian cell lysate Marcel Bruchez 108542 pLenti-EF1a-Luciferase-IRES-Blast-WPRE...not secreted, so cells must be lysed or the substrate must be delivered intracellularly in order to measure... viral infection efficiency, to study changes in cell physiology, or as a reference level of expression...interactions , protein dimerization , endosomal escape of cell-penetrating peptides , and more. nLuc/cLuc for split...Resonance Energy Transfer (BRET) CalFlux VNT : An intracellular calcium sensor created by fusing NanoLuc® and... -
Brain Initiative Collection
TypeCollection...Gordon Fishell 83899-AAV1 pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...Gordon Fishell 83899-AAV9 pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...Gordon Fishell 83899-AAVrg pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...real-time interrogation and monitoring of brain cells and circuits during behavior. Long desired by researchers...A somatic channelrhodopsin, which enables single cell, single millisecond resolution optogenetics. Human...A somatic channelrhodopsin, which enables single cell, single millisecond resolution optogenetics. Cre-dependent...genetically encoded dopamine sensor RdLight1 in mammalian cells. Lin Tian 125708-AAV9 pAAV-hSynapsin1-RdLight1 Expresses... -
Five Popular Model Organisms, Part 2
TypeBlog Post... H. J. (2009). Rats! Disease Models & Mechanisms, 2(5–6), 206–210. https://doi.org/10.1242/dmm.002733 ...are often used to study vertebrate embryology and cell development. One major resource for frog research...Organism to Study and Model Human Genetic Disease. Cells Tissues Organs, 205(5–6), 303–313. https://doi.org... -
Viral Vectors 101: Optogenetic Tools
TypeBlog Post...Optogenetic control of intracellular signaling pathways. Trends in Biotechnology, 33(2), 92–100. https://doi.org...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...Hegemann, P., & Bamberg, E. (2003). Channelrhodopsin-2, a directly light-gated cation-selective membrane ... -
Plasmids 101: Dimers and Multimers
TypeBlog Post...identification. Fig. 2: Gel image of Plasmid 61564: pBAMD1-2 (~4.7 kb) digested with SpeI and...to the formation of plasmid multimers. Cell. 1976 Dec;9(4 PT 2):707-16. doi: 10.1016/0092-8674(76)90134... at ~3.6 kb and ~1.1 kb (lane 3). Uncut DNA (lane 2) has a band at <3 kb, which corresponds to the supercoiled...dimers in Escherichia coli K-12. Plasmid. 1989 Mar;21(2):138-41. doi: 10.1016/0147-619x(89)90057-7. PMID: ...Plasmids and Chromosomes. Microbiol Spectr. 2014 Oct;2(5). doi: 10.1128/microbiolspec.PLAS-0025-2014. PMID...Behavior of Plasmid DNA. Microbiol Spectr. 2015 Apr;3(2):10.1128/microbiolspec.PLAS-0036-2014. doi: 10.1128...at lower copy numbers within bacterial cells, and bacterial cells with multimers grow more slowly compared... -
Flow Cytometry Readouts: Yes, No, and Everything in Between
TypeBlog Post...low expression, and everything in between (Figure 2). These smears tend to occur when you are looking ...on your experiment. You can see from Figure 2 that determining where to place your gate based on the dot... dot plot would be complicated. Figure 2: (A) a smeary dot plot showing a range of antibody readouts...plot in Figure 4 compared to the dot plot in Figure 2. Quantification using MFI makes it easier to identify...percentage of total live cells are GFP+. In this plot, with adjusted voltage, cells that did not receive ...would serve you well. Percentage of cells in a parent gate (all live cells for example) that are positive ...example, you have introduced a GFP protein into your cells (visualized via the FITC channel) and you are trying... -
CRISPR 101: Targeting RNA with Cas13a (C2c2)
TypeBlog Post...question: C2c1, C2c2 and C2c3 (short for Class 2, candidate 1, 2, or 3). C2c1 and C2c3 are related to Cpf1,...characterization of diverse class 2 CRISPR-Cas systems." Molecular cell 60.3 (2015): 385-397. PubMed PMID...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...thought to activate programmed cell death or a dormant state for bacterial cells that have been infected with...bacterial cells, LwaCas13a does not display nonspecific RNA cleavage activity in eukaryotic cells. They arrived...target RNAs, although its usefulness in bacterial cells will likely be limited by the propensity of Cas13a... -
MXS Chaining
TypeBlog Post...Tethering partner Subcellular localization 1 TagBFP 399nm/ 456nm histone 2B (H2B) Chromatin 2 Cerulean 433nm...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...protein localization, as well as cellular processes like gene expression and cell migration (Sladitschek and... MXS-chaining were used to label subcellular structures in live cells. Four individual expression constructs... -
AAV Titers: Where Do They Come From And What Do They Mean?
TypeBlog Post...PubMed Central PMCID: PMC3640491. 2. Grimm, D., et al. "Titration of AAV-2 particles via a novel capsid ELISA...report the physical titer of a viral solution (Figure 2). Because physical titers are used for dosing purposes...mean and how they can be compared. Figure 2: Label that comes on Addgene’s AAV aliquots. Our titer...of genomes can limit production of recombinant AAV-2." Gene therapy 6.7 (1999). PubMed PMID: 10455443. ...Characterization of a recombinant adeno-associated virus type 2 Reference Standard Material." Human gene therapy 21.10...particles that can transduce cells. Infectious titers are typically quantified by cell transduction assays. Wild-type... -
CRISPR Antimicrobials
TypeBlog Post...Citorik Plasmids here). In both cases, they used 1-2 CRISPR crRNAs targeting sequences found only in certain...resensitize antibiotic-resistant bacteria (Figure 2). The first phage introduced is lysogenic, integrating...machinery targeting 1) the given resistance gene and 2) a second lytic phage. Bacteria that receive this ...bacteria have previously flourished. Figure 2: Two-phage strategies to resensitize bacteria to antibiotics...237163. Find plasmids from this paper at Addgene. 2. Bikard, David, et al. “Exploiting CRISPR-Cas nucleases...reach essentially every cell or else small pools of antibiotic resistant cells could repopulate the environment...strategies are nonspecific - they harm any bacterial cell without a resistance gene, allowing resistant bacteria... -
New Neuroscience Tool: The iGluSnFR3 Glutamate Sensor
TypeBlog Post...kinetics which are illustrated in figures 2 and 3. Figure 2: Glutamate titration curves for the different...signals upon sensing glutamate using both 1-photon and 2-photon imaging. Figure 1: 1P and 2P excitation...adapted from Aggarwal et al…, Supplementary Figure 2. Improved trafficking and localization through... glutamate release from neurons and other brain cells in vivo. Glutamate plays a variety of roles in synaptic...sensor to the membrane and displays it on the extracellular side. In addition to the original PDGFR TMD,...promoter, FLEXed for expression in Cre-expressing cells hSynap: Human Synapsin-1 promoter. Good for neuronal...promoter, FLEXed for expression in Cre-expressing cells. hSynap-FLP: Synapsin-1 promoter, FLP-dependent ... -
Common Injection Routes in Mice
TypeBlog Post...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 ...different substances can be injected, including cells, drugs, DNA, viral vectors, and viruses. All researchers... injections are most often used when injecting a cell suspension to create xenograft models. Restraint... -
22 Hot Plasmid Technologies from 2014
TypeBlog Post...Currently available from the Kim lab are 2 presynaptic and 2 postsynaptic targeting mGRASP plasmids. Additionally... Robinson et al., Dev Cell 2010 Feb 16;18(2):324-31. Cheeseman et al., J Cell Sci 2013 May 1;126(Pt ... 2µg/ml of Doxycycline for 2 hours, and imaged on the Keyence BZ-9000 fluorescence microscope 8 hours ...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... -
CRISPR Plasmids - Empty gRNA Vectors
TypeCollection...Cas enzymes? CasPEDIA is an encyclopedia of Class 2 CRISPR systems with wiki entries describing enzyme...BclI-SwaI none S. pyogenes URA3 Wyrick pCRISPomyces-2 61737 Bacteria BbsI yes, cut S. pyogenes Apramycin... S. pyogenes Zhang gRNA Cloning Vector Bbs I ver. 2 85586 Mammalian BbsI None S. pyogenes H Fujii pX601...Cas protein and a target-specific gRNA in the same cell at the same time. Single plasmids containing both...Alternatively, gRNA-only plasmids can be used in cells or organisms in which Cas9 has been integrated into... -
Hassle-free 96-well Format Epitope Tagging Using Cas9 Ribonucleoprotein
TypeBlog Post...purify IVT sgRNA in the lab. Figure 2: Cas9 RNP complexed with 2-part cr:tracrRNA tags genes more effectively...is then transfected into stem cells. Cells are allowed to recover for 2-5 days and then analyzed for tagging...transfect and let cells recover for 2-5 days.Note: We use the Nucleofection method for delivery of csRNP... knock-in efficiency (<2% positive by ICC for the tag) or do not see any cells positive for tag insertion...stem cells. Development 144: 635-648. PubMed PMID: 28096221. PubMed Central PMCID: PMC5312033. 2. Dewari...IVT sgRNA) approach (Dewari et al. 2018 and Figure 2). Not only is the cr:tracrRNA approach highly efficient...transfected cells, we count the number of tag-positive cells (tag ICC) as a percentage of total cells in the... -
Easi-CRISPR: Generating Knock-In and Conditional Mouse Models
TypeBlog Post...of conventional gene targeting is lowered to about 2-3 months. But certain models remain more difficult...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...desired mutation in mouse ES cells, select for the mutation and inject the ES cells into a mouse embryo to ... -
An Introduction to Adenovirus
TypeBlog Post...either SARS-CoV-2, Adenovirus type 41 (AdV-41), or Adenovirus-Associated Virus type 2 (AAV2) – or some... was either 1) a physiological effect of SARS-CoV-2 toward destabilizing one’s natural immune response...response to Adenovirus (and/or to its partner, AAV) or 2) a sociological effect of the COVID-19 lockdowns causing...… Chiu, C. Y. (2023). Adeno-associated virus type 2 in US children with acute severe hepatitis. Nature... AdVs is dependent on modulation of the host cell’s cell cycle; inhibition of the innate immune system... in the producer cells where there is E1 and E3 gene complementation. In target cells that are infected...hexon), as well as other intracellularly-exposed proteins and downstream cellular events, all recruit strong...