We narrowed to 587 results for: cel.2;
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TypeBlog Post...(you generally don’t want more tag than protein), 2-3 tags is increasingly common. Tandem affinity purification...TEV cleavage site (more on that in a moment), and 2 ProtA IgG-binding domains. TAP has since come to encompass...found in this paper (available at Addgene). Table 2: Protease recognition sites commonly used with tags...not generally in a cell’s best interest to overexpress a protein. Energy and cellular resources are being...being spent to make something the cell doesn’t need to make. Eukaryotes and some bacteria deploy proteosomes...proteosomes to degrade what the cell might consider junk protein. Though there are a number of chemical and...same manner as it would have in the context of a cell. FLAG tags can be cleaved by enterokinase, which...
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Spurred by COVID-19, Addgene Bridges Plasmid Sharing Between Academia and Industry
TypeBlog Post...untagged expression of SARS-CoV-2 proteins in bacteria, yeast, and mammalian cells. We teamed up with Ginkgo...approximately 3,000 constructs to support SARS-CoV-2 research. Browse the entire Ginkgo Bioworks COVID...organizations to share materials more broadly to accelerate COVID-19 research: Sinai Health System ... -
Deep Dive: qPCR
TypeBlog Post...indicating primer dimers. (c) A double peak indicating 2 amplicons. Image credits (respectively): Zuzanna K...details for reproducibility’s sake! Fig. 2: Setting up triplicates in multiple configurations...used method is the Standard Curve method. See Table 2, (adapted from Wong, 2018) for a comparison of different...Statistically defined log-linear phase Table 2: A comparison of different qPCR analysis methods. ... for RNA quantitation. Biotechniques. 2000 Aug;29(2):332-7. doi: 10.2144/00292rv02. PMID: 10948434.Taylor... that your reference genes are suitable for your cell lines and/or tissue types. Please do note my oh-so-subtle...reference genes to save on plate space. For many cell lines and tissue types, appropriate reference genes... -
ReFigure: Save Scientific Figures into Dashboards and Share Your Insights
TypeBlog Post...literature? Very often the data of interest are in 1 or 2 figures from one paper and then another figure in ...ReFigure by creating ReFigures and answering this 2 minute survey! You can also find ReFigure on Twitter... remember what happened when drug X was added to cell line Y, or the phenotype of a mouse with a specific...comparison of the same experiment from different cell lines/model systems ReFigure allows you to make... -
Antibodies 101: Reading a Flow Plot
TypeBlog Post...you look at the dot plot in Figure 2, you might assume that all cell populations are positive for both ... the case of Figure 2, one population is B- and another two are B+. Our A-B+ cells are in the lower right...right corner. Figure 2: This flow plot has two populations that are B+ and one population...-B+ cells, and A+B+ cells, but no cells that are A+B-. Figure 3: It's often easier to identify...population of B cells and dendritic cells (DCs) in the lower middle right. DCs and B cells are HLA-DR+ and...single cells in a population. It can be used to measure protein expression, identify rare cells, or even...looking for cells in a sample that are negative for marker A and positive for marker B, or A-B+ cells. If you... -
Comparing Cas9 to NgAgo: Can the Argonautes Best CRISPR?
TypeBlog Post...Epub 2016 May 2. PubMed PMID: 27136078. Find plasmids from this publication at Addgene. 2. Swarts, Daan... be stable in the cell. gDNA guides will also need to be transfected into the cells of interest. In contrast...unable to show TtAgo-mediated cleavage in mammalian cells, likely due to high temperature requirements. To...plasmid and genomic DNA in a variety of mammalian cell lines, with an efficiency similar to that of Cas9... -
New Acoustic Reporter Genes: Ultrasound Imaging of Gene Expression
TypeBlog Post...starting day 2 after transfection. Fig: 2: Expressing mARGAna in MDA-MB-231 cells. (a) Plasmid...expression. When engineering a cell line, cotransfect the mARG cassettes 2:1 (A:N-V) with PiggyBac transposase...producing cells. After FACS, return the cells to doxycycline-free media and expand the cells. Use a subset...white inclusions in cells with GVs via phase contrast microscopy, GVs visible in cells via TEM, and purified... heterogeneity required single cell screening to isolate a clonal cell line capable of producing ultrasound...expression homogeneity, as the cells could be batch-sorted to isolate a polyclonal cell line with strong gas vesicle...transient transfection in rtTA+ cell lines (such as HEK293-TETOn cells), or they can also be integrated... -
Tips for arabidopsis transformation
TypeBlog Post... Plant Methods. BioMed Central, 2(1), p. 19. doi: 10.1186/1746-4811-2-19. PubMed PMID: 17087829. PubMed...PMID: 24032037. PubMed Central PMCID: PMC3759027. 2 Harrison, S. J. et al. (2006) ‘A rapid and robust ...incubated at stationary phase for too long, the cells in your culture will no longer be viable. The time...graduate student at Stanford University. She studies cell fate maintenance in the stomatal lineage and has... -
Plasmids 101: Plasmid Incompatibility
TypeBlog Post...daughter cell, instead of partitioning each type of plasmid into a separate daughter cells (Figure 2) (Ebersbach...to plasmid loss (Diaz et al., 2015). Figure 2: The partitioning problem. For low copy plasmids...Plasmids. Microbiology and Molecular Biology Reviews 62(2): 434–464. Pubmed PMID: 9618448 Diaz R, Rech J, Bouet...copy number in the cell is high, but allows replication when copy number in the cell falls too low (Novcik...system to partition themselves to each daughter cell during cell division. They don’t simply rely on chance...eukaryotic cells). The partition NTPase is recruited and “walks” each plasmid to a separate daughter cell. When...from the cell with the same probability, or asymmetrical, where one plasmid lost from the cell at a higher... -
FastCloning: A Newer, Simpler Cloning Technique
TypeBlog Post...vector:insert ratio is used in the DpnI digestion and 2 µL of digest product are used in the transformation...Biology 38 (2016): 145-154. PubMed PMID: 27391134. 2. Li, Chaokun, et al. "FastCloning: a highly simplified...properly. Directly transform chemically competent cells with the digested mixture. There is no need for ...purification before transformation. After transforming cells, you should perform colony PCR with vector specific...interested in protein science. References: 1. Celie, Patrick HN, Annabel HA Parret, and Anastassis Perrakis... -
Tips for CRISPR Gene Editing in Mice
TypeBlog Post... than control, 3; same as control (Cetn1/sgRNA1), 2; darker than control, 1; very dark). Brighter fluorescence...you can hold off on genotyping until the pups are 2-4 weeks old and use the ear tag method (creating different...PMID: 24253446. PubMed Central PMCID: PMC3875854. 2. Mashiko, Daisuke, et al. "Generation of mutant mice...expanded since its adaptation for use in mammalian cells in 2012-2013. Researchers are now using this system...plasmids containing sgRNA sequences into HEK293T cells. The fluorescence intensity was classified into ...is then a simple matter of transfecting HEK293T cells with your modified pCAG-EGXXFP plasmid along with...incubation, you assess the level of fluorescence in your cells under a fluorescence microscope. The higher the ... -
Selecting Your Plasmid Purification Kit
TypeBlog Post... environmental sustainability in mind (Table 2). Table 2: Sustainability features highlighted in plasmid...plasmid DNA from unwanted cellular “debris”; and then clean-up the plasmid DNA (Figure 2). For most kits, the...together — no mixing and matching! Figure 2: Plasmid isolation workflows are similar across kits...the steps for lysing cells and removing cellular debris look very similar. However, keep in mind that ...relative term — even armed with the highest-competency cells you will still struggle to get transformants if ...quantity) – Depending on the experiment, mammalian cell transfections can require quite large amounts of...your bacteria to release the plasmid, separate the cell debris from the plasmid, and then clean-up the plasmid... -
What's Your Organism? Expanding Genomic Tools via the NSF EDGE Program
TypeBlog Post...presented in a series of quick (10 minute) or very quick (2 minute) talks so we got to hear from everyone. Addgene...evolutionary tree at least 6-7 times and on at least 2 separate continents. Mimulus (Andrea Sweigart) Monkeyflowers...Organisms, Part 1 Five Popular Model Organisms, Part 2 ...Xenopus frog cell lines to develop robust methods for frog gene editing. They edit in a cell line, then ...is the smallest photosynthetic cell in existence, but most abundant cell on earth (twice the human biomass...only 1,700 genes total). Hydra (Celina Juliano) This is a known stem cell and regeneration model. Little...Mormyridae (Jason Gallant) Weakly electric fish are excellent systems to study for convergent evolution because... -
Adeno-associated virus (AAV) Guide
TypeGuide...capsids from serotypes 1, 2, and 5 display differential efficiency and cell tropism after delivery to ...packaging and producer cell lines for the production of AAV vectors . Microorganisms, 12 (2), 384. https://doi.org...components, see the AAV Plasmid Elements table . Figure 2: Plasmids required for rAAV vector production. Created...the central nervous system . Molecular Therapy, 10 (2), 302–317. https://doi.org/10.1016/j.ymthe.2004.05.024...retrograde access to projection neurons . Neuron, 92 (2), 372–382. https://doi.org/10.1016/j.neuron.2016.09.021...based on other human cell lines, such as HeLa and A549 cells, and even insect Sf9 cells , have also been ...able to infect cells and replicate autonomously. Human embryonic kidney 293T (HEK293T) cells are the most... -
Antibodies 101: Introduction to Immunofluorescence
TypeBlog Post...into the several steps outlined below and in Figure 2. For a deeper dive into the steps and techniques, ...mounting sample on slides, and confocal Figure 2: High-level overview of an indirect immunofluorescence...recognize the species of your primary antibody and 2) is conjugated to a fluorophore that suits your experiment...interest live within a cell,” “Does this disease change the architecture of my cells,” or “How does this ...IF), is an immunoassay that brings to light the cellular world. The technique allows you to ask questions...this mutation impact the types of cells found in my tissue.” It is based on the same principles as other ... visualize a target of interest within an intact cell, tissue, or, in some cases, a whole organism. But... -
The PAM Requirement and Expanding CRISPR Beyond SpCas9
TypeBlog Post...Endonuclease of a Class 2 CRISPR-Cas System. Cell 163:759–771 . https://doi.org/10.1016/j.cell.2015.09.038 Find...is unique compared to the rest of the genome and (2) the sequence is located just upstream of a Protospacer...pyogenes Cas9 variants with varying PAM sequences, 2) the use of Cas9 homologs derived from species other...are capable of cleaving genomic DNA in mammalian cells and zebrafish embryos, and they can be used to modify... adapted for targeted RNA cleavage in mammalian cells. The REPAIR (RNA Editing for Programmable A to I...reveals specificities of Cpf1 endonucleases in human cells. Nat Biotechnol 34:863–868 . https://doi.org/10.1038...specificities of CRISPR-Cas Cpf1 nucleases in human cells. Nat Biotechnol 34:869–874 . https://doi.org/10.1038... -
Fluorescent Proteins 101: Luciferase
TypeBlog Post...native enzyme, which are summarized in Table 2 below. Table 2: Properties of native luciferases Organism...luciferase assays require cell lysis as the most efficient means to disrupt the cell membrane and deliver ...miRNAs for effectiveness. Analyze Cell Signaling Pathways Known cellular signaling pathways can be investigated...luciferase as a genetic reporter in plant and mammalian cells. Luciferase assays have since become a gold standard... serves as an indicator of transcription within cells, where detection of the reporter protein or its .../Phototoxicity Not susceptible Susceptible Subcellular Imaging Improving Well-established High-throughput... into the desired mammalian, plant or bacterial cells. Expression of luciferase as the reporter gene is... -
Visualizing Translation at the Single Molecule Level
TypeBlog Post...the reporter mRNA is labeled by PCP-mCherry (Figure 2). The 3’ UTR also contains a CAAX sequence to bind...PMC2746483 Find ribosome profiling plasmids at Addgene. 2. Halstead, James M., et al. “Translation. An RNA biosensor... of all of the mRNA bound-ribosomes in a cell. When cellular mRNAs are digested with ribonucleases, ribosomes...Regulating translation is key to cellular function, especially during development or stress. With ribosome...explore the complexity of translational control in cellular physiology. Ribosome profiling Ribosome profiling...the effects of 5’ UTR variants in translation of cell cycle protein Emi1, showing that ~80% of transcripts...powerful tools for studying translation in various cell types and physiological states. References 1. Ingolia... -
Hot Plasmids - September 2019 - CRISPR, Auxin Inducible Degradation, MerMAID Channelrhodopsins, and Genome Looping
TypeBlog Post...Mammalian genomic DNA is not just a 2-D linear molecule snaking through our cells’ nuclei--our chromatin is comprised...target sites for editing. PAM sequences can be from 2-6 base pairs in length and follow the DNA sequence...plant protein TIR1 in non-plant cells, which interacts with the cells’ endogenous ubiquitin ligase, the...translate AID to yeast, as well as mammalian and human cell lines (Nishimura et al., 2009, Natsume et al., 2016...based method to tag endogenous proteins in HCT116 cells with mAID. Using this method, the lab was able to... protein of interest to create conditional human cell lines. Lastly, the Kanemaki lab demonstrated that...the target sites adjacent to an NG PAM in human cells. The increased versatility of the engineered SpCas9... -
Hot Plasmids: Fall 2024
TypeBlog Post...improve solubility and stability (Figure 2). Figure 2: Crystal structures of CRBNmidi alone...fluorescent tags in Caenorhabditis elegans. Genetics, 228(2), iyae126. https://doi.org/10.1093/genetics/iyae126...useful addition to the toolkit for visualizing cellular processes in C. elegans: mScarlet3 for applications...biologically relevant forces at focal adhesions in living cells in several different contexts. Figure ...substrate furimazine. Right: Demonstration of PILATeS. Cell adhesion to a PILATeS-functionalized coverslip creates... -
Antibody Guide
TypeGuide...surface of most immature B cells; function is unknown Monomer with a valency of 2 IgE Protects against parasites...such as anaphylactic shock Monomer with a valency of 2 IgG The most abundant isotype in blood, also found...secondary immune response Monomer with a valency of 2 IgG1; IgG2; IgG3; IgG4 IgM Produced during the primary... ranging from antibody fragments (shown in Figure 2) to completely unrelated molecules. Examples include...used for assembling protein nanostructures. Figure 2: An antibody (IgG, far left) compared to alternative... produced. Cells - Antibodies can also be produced in cell cultures using hybridomas, cell cultures created...created by fusing B cells with myeloma cells (immortalized B cells). The genetic reorganization that creates... -
Droplet Digital PCR for AAV Quantitation
TypeBlog Post... qPCR is that the results can vary by a factor of 2. This means that if you set up two identical assays...amplitude measured for each droplet in each well (Figure 2). A clean ddPCR should have a clear separation between...as low as 1C/s. Increasing the elongation time to 2 minutes and the denaturation time to 1 minute has ...used in the detection of rare sequences and single cell analysis. It is also being used in the detection... -
Antibodies 101: Introduction to Gating in Flow Cytometry
TypeBlog Post...represents the time and intensity of the cell’s illumination (see Figure 2). H describes the maximum signal strength...most people use that setting. Figure 2: As the cell passes through the laser beam and causes it...proportion (while H and W do not; see Figure 2), single cell events will show up in a straight line one ...Many cell types can be found in the tumor microenvironment (tumor cells, immune cells, blood cells and ...about 53% of my cells are dendritic cells and ~13% are CD8+ T cells. Around 34% of the cells are neither ...neither of the two cell types (likely B cells and others). Almost no cells stain positively for both markers...measure your cells of interest. In many experiments you’ll be working with a heterogeneous cell population... -
Plasmids 101: Broad Host Range Plasmids
TypeBlog Post...host range plasmids. FEMS Microbiology Letters, 348(2), 87–96. https://doi.org/10.1111/1574-6968.12241 ...mobilization of broad host-range IncQ plasmids. Plasmid, 62(2), 57–70. https://doi.org/10.1016/j.plasmid.2009.05.001...negative hosts. Biotechnology and Bioengineering, 106(2), 326–332. https://doi.org/10.1002/bit.22695 Schmidhauser...ability to establish and maintain itself within host cells. The plasmid has multiple ori that are functionally...eutrophus, Bartonella bacilliformis, Bordetella spp., Brucella spp., Caulobacter crescentus, Escherichia coli... -
Antibodies 101: Single Chain Fragment Variables (scFvs)
TypeBlog Post...panning and scFv characterization. Figure 2: Phage display starts with a pooled library of scFvs...the short epitope GCN4, also called a scaffold; and 2) a GCN4 binding scFv that’s fused to GFP. When the...Fv (Variable Domain) (scFv) Fragments. Antibodies 2:193–208 . https://doi.org/10.3390/antib2020193 Khantasup...scFvs and T cell receptors and are expressed on T cells to make CAR T cells. The extracellular scFv portion...Bispecific T-cell engagers (BiTE®s), bind CD3 on T cells and a tumor-specific antigen, it brings T cells to a ...recognizes an antigen of interest while the intracellular T cell receptor portion of the CAR facilitates ...scFv part of the receptor can activate T cells to kill cancer cells. scFv’s small size also allows for their... -
Filming Science Videos in the Age of Social Distancing
TypeBlog Post... Figure 2: Ironing boards. Good as a WFH desk, and as a video control center. Cycle 2: Zooming ...ironing board, giving it the perfect height (Fig. 2). We recorded video using a simple, external video...Zooming Forward Design: We produced a video celebrating Massachusetts Nonprofit Day, which was the perfect opportunity... Quintin Marcelino... -
Cancer, Inflammation and Immunity - Harnessing the Body’s Defenses to Fight Cancer
TypeBlog Post...immunosurveillance." Cancer cell 30.1 (2016): 147-160. PubMed PMID: 27411589. 2. Todoric, Jelena, Laura Antonucci...represent a favorable state for tumor progression (Ref 2). Future treatments may need to target this immunosuppressive...cancers. It was inspiring to participate in the 2017 Cell Symposium on Cancer, Inflammation and Immunity and...recent findings in basic immunology, cancer-immune cell interactions, cancer immunotherapy, as well as new...immunosurveillance. The presented study analysed a model of hepatocellular carcinoma, a cancer which can develop from ...example the upregulation of the immunosuppressive cell surface receptor PD-1. This immunosuppressive environment...follow the interactions between tumor and immune cells in real time. Addgene depositor Professor Max Krummel... -
Visualizing Genomic Loci with CRISPR-Sirius
TypeBlog Post... variation (CNV) analysis of the U2OS cells. Figure 2: CRISPR-Sirius tricolor labeling. (A) ...that the signal to noise ratio can be increased from 2-fold (by CRISPRainbow) to 3-fold with CRISPR-Sirius... to date for visualizing genomic loci in living cells. Previous iterations of genomic loci visualization...labeling system to visualize chromosomal loci in human cells (Ma et al., 2015). To do so, they fused a different...visualization of sites on different chromosomes in living cells, the system requires high-copy chromosome-specific... aptamer system to visualize the gRNA in living cells. Broccoli aptamers are nucleic acid sequences that...production needed to deliver CRISPR-Sirius into cells. They named this guide sgRNA-Sirius-8XMS2 which ... -
Antibodies 101: Flow Cytometry Controls
TypeBlog Post...otherwise be difficult to separate out. In Figure 2, you can see that, without the FMO, it would be difficult... from the Ly6C positive population. Figure 2: An FMO gating example. The FMO sample (A) can be ...and beads that are unable to bind to them: like cells but with far more predictability. The beads create...The benefit of beads is that they do not require cells from your experiment, and they are non-specific....flow cytometer, you generally want your positive cells to read between 104 and 105 in order to have enough...the plot to see all of your positive and negative cells. This can be achieved by adjusting your voltage ...gating schematic to easily determine where your cells of interest are (B). Using FMO controls In... -
Quick Guide to Working with Drosophila Part 2: Controlling Gene Expression in Flies with Gal4/UAS
TypeBlog Post... you can read more about them in review articles (2–4). You can also take a look at my recent paper to...Development 118, 401–15 (1993). PubMed PMID: 8223268. 2. J. B. Duffy, GAL4 System in Drosophila : A Fly Geneticist... to express one gene in one cell type and another gene in a different cell type (6–8). Although it’s often...systematically study gene function with temporal control and cell-type specificity! The Gal4/UAS system At a more...the hedgehog gene can be overexpressed in several cell types by using different Gal4 drivers. It is much...much easier to mate flies to get the right cell type expression as opposed to making a new fly with hedgehog... Targeted gene expression as a means of altering cell fates and generating dominant phenotypes., Development... -
Hot Plasmids - January 2023
TypeBlog Post...is always best to have options. Fig. 2: Addgene’s western blot for mEGFP-HRas (from Plasmid...the presence of oxidizing agents. Adapted from Fig. 2 Campbell et al, Nature Methods Find YFP plasmids...mCherry for FACS sorting of the weaponized T-cells (CAR-T cells) - and then delivering them to a tumor - ...effectively as standard CAR-T cells, but it reduces the off-target effects caused by T cell migration. CAR expression...reducing the on-target off-tumor activity of CAR–T cells was recently devised by the Yingxiao Wang lab. ...above can be made for expressing your favorite T-cell receptor, or perhaps any other tool that can benefit... Wu Y, et. al. Control of the activity of CAR-T cells within tumours via focused ultrasound. Nat Biomed... -
5 Great Apps for Lab Life
TypeBlog Post... you’re saving trees! The Earth thanks you. 2. Gibco Cell Culture by Gibco Whenever I start to learn a...misplacing your results or losing that lab notebook from 2 years ago. The free subscription to Lab Archives allots...spectrometry app. I digress. When I started learning proper cell culture technique, I tried to find an app that could...calculations. This is how I came across the Gibco Cell Culture app. Gibco organizes its app into four categories...tools are a lifesaver when your research requires cell culture and include a counter, lab timer, dilution...educational section. This section holds the Gibco Cell culture manual and basic instructional videos. The... Overall, it’s a great tool for someone starting cell culture work. 3. NEB Tools by New England BioLabs... -
Evolution of Lab Techniques
TypeBlog Post...mutation is the genetic test used for sickle cell anemia (2). Southern blotting, in conjunction with restriction...1195397. 2. Chang, Judy C., and Yuet Wai Kan. "A sensitive new prenatal test for sickle-cell anemia." ...program) can then reproduce the DNA sequence (Figure 2). Accuracy and accessibility led to the widespread...Neuroscience at Harvard University. Just as computers, cell phones, and cars become more technologically advanced... of the mutated β globin gene that causes sickle cell anemia. The mutation happens to destroy a sequence...conducted on a sample from an individual without sickle cell anemia, two DNA fragments are observed because the... site where MstII cuts. In a patient with sickle cell anemia the enzyme does not cut the DNA so only one... -
CRISPR 101: Off-Target Effects
TypeBlog Post...generate a knock-out cell line to perform downstream characterization of, isolating 2 or 3 distinct clones...sites would confound your experimental results and 2) perform targeted off-target measurements at those...experiments where only localization of the Cas occurs. 2 gRNA approach Off-targets that come from mutations...millions of cells. For every individual sgRNA, you recover a minimum of 1,000 targeted cells to sequence...trying to generate a knockout cell line, with the goal of isolating single cell clones to use for multiple...generate a ssDNA break which can easily be repaired by cells with a near zero likelihood of mutation arising.... a level of, say 5%, then the majority of single cell editing events will be on target. Thus, if you isolate... -
DAP arrays for multiplex gene editing
TypeBlog Post...disease, and type 2 diabetes, across four different types of human cells, including T cells and hematopoietic...(#186715) and hCtRNA_VT (#186716). Fig. 2: Comparison of previous representative dual-gRNA architectures...to enable multiplex gene editing in a variety of cells and organisms. However, lengthy genetic payloads... over 50% averaging editing efficiency in human cells. MBE with DAP array also exhibited reduced Cas9-...hematopoietic stem and progenitor cells. Now with the DAP array, it is possible to use the state-of-art base editor... editing, and nuclease editing, in virtually any cell type or organisms of interest with only minimal ... -
Plasmids 101: Common Lab E. coli Strains
TypeBlog Post...Table 2: Lab strains of E. coli Strain Natural resistance Primary Use Genotype ccdB Survival 2 T1R ...resistance to tetracycline Additionally, Table 2 provides a quick reference for some of the popular...degraded, cell still can methylate DNA hsdS(rk-,mk-) Unmethylated DNA not degraded, cell cannot methylate... gal Mutation in galactose metabolism pathway Cells cannot grow on galactose only gyrA, gyrA96 DNA...permease inactivated, lactose cannot be taken up by cell mcrA, mcrBC Inactivation of pathway that cleaves...gene that maintains the plasmids at ~250 copies per cell. F- ∆lac169 rpoS(Am) robA1 creC510 hsdR514 endA...rpsL20 xyl-5 leu mtl-1 Stbl4 Electrocompetent cells for cloning and storage of unstable DNA and lentiviral... -
Synthetic Photobiology: Optogenetics for E. coli
TypeBlog Post...Marcotte EM, Voigt CA. Nature. 2005 Nov 24;438(7067):441-2. PubMed. Find the plasmids from this publication ...Levskaya A, Voigt CA. J Mol Biol. 2011 Jan 14;405(2):315-24. doi: 10.1016/j.jmb.2010.10.038. Epub 2010...Voigt CA, Ellington AD. Cell. 2009 Jun 26;137(7):1272-81. doi: 10.1016/j.cell.2009.04.048. PubMed. Find...with sophisticated gene expression controls. Most cell types do not respond to low-intensity light, so ... -
New Tool for Lineage Tracing: The ClonTracer Library
TypeBlog Post...same parent cells that represent the preexisting resistant subpopulation 2. Resistant cells among the separate...440-448. Pubmed PMID: 25849130. 2. Hata, Aaron N., et al. "Tumor cells can follow distinct evolutionary...resistant cancer cells exist prior to drug treatment. They infected a non-small cell lung cancer cell line containing... target cell population at low multiplicity of infection (MOI) such that each individual cell receives...researchers to individually label millions of mammalian cells through lentiviral infection and to monitor their...quantify the take rate of mouse xenografts after cell implantation. Their goal was to figure out how to...ClonTracer library to determine whether or not cancer cell populations resistant to drug treatments arise during... -
FlipGFP, a novel fluorescence protease reporter to study apoptosis
TypeBlog Post...parts: (1) β-strands 1-9 (β1-9) and the one ɑ-helix, (2) β-strand 10 (β10), and (3) β-strand 11 (β11). Each...activating caspase-3, and detected fluorescence within 2 to 5 hours, a time consistent with previous methods...the degradation of over 600 cellular components ultimately leading to cell fragmentation and death (Elmore...issues with tissue autofluorescence, cell heterogeneity, and/or cell position changes (To et al., 2016, ...apoptosis in HeLa cells, zebrafish embryos, and Drosophila. They treated HeLa cells expressing FlipGFP...cleavage by executioner caspases. Failure for cells to die or cells dying at the wrong time and/or place can...Apoptosis or “programmed cell death" plays a pivotal role in an array of biological processes including... -
Top Requested Lentivirus and AAV of 2016
TypeBlog Post... tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain. PLoS One. 2013 ...PMID: 24086725. PubMed Central PMCID: PMC3785459. 2. Krashes MJ, Koda S, Ye C, Rogan SC, Adams AC, Cusher...expressed in cells that express cre recombinase. Typically, this feature is used to attain cell-specific ...tools so that researchers around the world can accelerate their work. After all, as we like to sayat Addgene...CRISPR applications and can be expressed from your cell line of choice after transduction with this virus...blast virus can be used to generate Cas9-expressing cell lines, which can then be used both for screens (...viral prep to create a single stable Cas9-expressing cell line and then transduce this line with lentiviruses... -
Twenty Years of Sharing: Expanding Accessibility
TypeBlog Post...China, Korea, Japan, Brazil, India, and Mexico. Table 2: Addgene distributors Distributor Partnership...distribution after we partnered with them (Figure 2). In others, the distributor helped solve an issue...temperature for the duration of their journey. Figure 2: Annual distribution of items to countries with a ...we are today. As part of our 20th anniversary celebration, we thought it only fitting to share some stories... -
Stabilized Bacterial Promoters: Constant Gene Expression at any Copy Number
TypeBlog Post...the number of plasmids per cell increases 4-5 fold (for pUC plasmids) or ~2 fold (for p15a, R6K, and ColE2...biotechnology 36.4 (2018): 352. PubMed PMID: 29553576. 2. Kittleson, Joshua T., Sherine Cheung, and JChristopher... engineer cells for specific purposes. Unfortunately, plasmid copy numbers vary within cell populations...problems. Rapidly dividing cells initiate genome replication more than once per cell division and thus, genes.... When cells are dividing rapidly, multiple rounds of replication are initiated before the cell has divided...growth rate can all impact plasmid copy number in a cell. One can attempt to eliminate fluctuations due ... pSC101 with copy numbers ranging from 3-100 per cell, a stabilized promoter buffered against the effects... -
Pooled CRISPR Libraries Offer Genome-Wide Control for Large-Scale Functional Screens
TypeBlog Post...VP64 fusion; 2. A sgRNA incorporating two MS2 RNA aptamers at the tetraloop and stem-loop 2; 3. The MS2...Ishitani R, Zhang F, Nureki O. Cell. 2014 Feb 27;156(5):935-49. doi: 10.1016/j.cell.2014.02.001. Epub 2014 Feb...Kampmann M, Weissman JS. Cell. 2014 Oct 23;159(3):647-61. doi: 10.1016/j.cell.2014.09.029. Epub 2014 Oct...screening for genes that, when turned on, make melanoma cells resistant to treatment with a BRAF inhibitor. (The...Addgene, enabling systematic investigation of the cellular consequences of repressing or inducing individual...Weissman and his colleagues demonstrated in a paper in Cell that they could typically achieve 90-99% knockdown...straightforward to apply the new library for use in various cell types and in live mice. Therapeutic uses in humans... -
Troubleshooting and Optimizing a Western Blot
TypeBlog Post... that all look exactly alike. Figure 2: Reagent gradient. Here, the lanes are lightly marked...guide. The gel is then removed from the membrane (2) and the membrane is cut so each lane is its own piece...in the bands, you may want to consult Tables 1 and 2 in our Technical Design of a Western Blot post to ...the antibody’s dynamic range. Specifically, the 1:2, 1:1, and No dilution samples all have approximately...conditions are 4 °C overnight or room temperature for 1–2 hours, there is some evidence that antibodies may ...check its subcellular location and solubility. If it’s membrane-bound or located in a subcellular compartment...reagent. Be aware that this approach requires excellent attention to detail, since you’ll end up with ... -
PiggyBac-ing Through the Genome Editing Field
TypeBlog Post...models or cells lines, including stem cells, without leaving behind any accessory DNA sequences [2], [3]....leaving behind only those cells with a Footprint-Free™ genome edit. Figure 2: Editing DNA using the...PMID: 26211958. PubMed Central PMCID: PMC4663986. 2. A. M. Singh, V. V Adjan Steffey, T. Yeshi, and D...transgenic cell lines? One of the major uses of the piggyBac™ system is to create stable transgenic cell lines...efficiency is likely to be cell line-dependent, and should be tested in the cell line of interest. Importantly...If the cell’s chromatin structure undergoes significant rearrangement (such as when a stem cell initiates...applications, including making transgenic cell lines and genetically-modified cell lines. Furthermore, the use of... -
Viral Vectors 101: Inverted Terminal Repeats
TypeBlog Post...ITR, which can either be “flip” or “flop” (Figure 2). Additionally, the ITR contains a 4-nucleotide Rep...site for Rep proteins (Savvy et al. 2013). Figure 2: AAV2 wild type ITR in flip and flop orientation. ...allow scientists to express a gene of interest in a cell or animal model. AAV plasmids contain several important...Integrity on rAAV8 Production Using the Baculovirus/Sf9 Cells System. Hum Gene Ther Methods, 28(5), 277–289. https... -
Targeted Mutagenesis with EvolvR
TypeBlog Post...while increasing the standard mutation rate by only ~2-fold over nCas9 levels. Two sets of modifications ...10-3 mutations per nucleotide per generation, and (2) the addition of the thioredoxin-binding domain (TBD...EvolvR could also be a tool for lineage tracing cells that do not tolerate double-strand DNA breaks by...researchers to trace the progeny of a single starting cell. Additionally, multiplexing of guides allows EvolvR... -
History of CRISPR Cas - A tale of survival and evolution
TypeBlog Post...phages but to also destroy the phage upon re-exposure (2, 3). More specifically, specialized Cas proteins snip..., accessed 25 November 2013. Author: James Atmos (2). Many CRISPR/Cas moieties carry out these functions...devise new strategies to reproduce within a host cell. A few virus particles have learned to circumvent... -
Even more elegant: Single injection CRISPR/Cas9 in C. elegans
TypeBlog Post...one injection step! The entire protocol takes about 2-3 weeks but requires less than eight hours worth of...for C. elegans genome modification. Figure 2: Schematic from Dickinson et al. (2015) illustrating...systems may prove effective in other species or in cell culture. In addition to CRISPR/Cas9 applications... -
R Bodies: Membrane-Rupturing Microscopic Tools
TypeBlog Post...be decorated with proteins and remain functional, 2) break membranes outside of their natural context ...PubMed PMID: 3759909. PubMed Central PMCID: PMC213417. 2. Schrallhammer, M. et al. Tracing the role of R-bodies... can rupture E. coli spheroplasts (cells which have had their cell walls removed with lysozyme). This ...protein fusions allowed us to image R bodies inside cells, and these constructs may be useful to future scientists...applications. For example, you could use them to lyse cells (and surrounding membranes) in keeping with their...penetrate other barriers (like vasculature or extracellular matrices) in response to pH changes. Beyond...assemble and function, we might be able to endow cells with new ways to interact mechanically with their...