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  1. Technical Design of a Western Blot

    Type
    Blog Post
    Published
    Aug. 22, 2024, 1:15 p.m.
    .... The most common options are 4 °C overnight or 1–2 hours at room temperature (RT). Most people choose...overnight at 4 °C and their secondary antibody for 1–2 hrs at room temperature, which allows them to reduce...Tris-glycine 6–400 kDa Tris-glycine 100 V, 1–2 hours Easy and cheap to handcast Short shelf-life...–40 kDa Tris-tricine 30 V, 1 hour or 100 V, 1–2 hours Good separation, quality, and stability ...separation of proteins of different sizes.  Table 2: Recommended gel percentages for various protein sizes...are consistent and stable at room temperature for 1–2 years and are available in formulas specific to your...response over a broad dynamic range that typically spans 2–5 orders of magnitude, which includes a wide dynamic...
  2. Delivery Methods for Generating iPSCs

    Type
    Blog Post
    Published
    April 17, 2018, 1:37 p.m.
    ... and future challenges." Journal of Cellular Physiology 228, no. 2 (2012): 267-75. PubMed PMID: 22767332...Pluripotent Stem Cells, 2013, 23-33. PubMed PMID: 23546745. PubMed Central PMCID: 4176696. 2. Yusa, Kosuke...Gene-delivery systems for iPS cell generation. Expert opinion on biological therapy, 10 2, 231-42. PubMed PMID:...plasmid-based expression requires serial transfection of 1 or 2 plasmids that express the reprogramming factors of...for generating iPSCs by plasmid transfection where 2 of 11 clones tested had plasmid integration. Another...understanding the mechanisms of reprogramming, and 2) studies with clinical endpoints. In the first scenario...PubMed PMID: 27764162. PubMed Central PMCID: 5072705. 2. Sommer, Cesar A., and Gustavo Mostoslavsky. "The ...
  3. 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,...
  4. Plasmids 101: Restriction Cloning

    Type
    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...use electro-competent cells instead of the more common chemically-competent cells. You should perform, ... manufacturer’s instructions for your competent cells. For most standard cloning, you can transform 1-...
  5. No Llamas Required - Synthetic Nanobodies Against Membrane Proteins

    Type
    Blog Post
    Published
    June 18, 2020, 1:15 p.m.
    ...select for optimal sybody candidates. Figure 2: Outline of the process for selection of sybodies ...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...Single-Domain Camelid Antibodies. Cell 181:1004–1015.e15 . https://doi.org/10.1016/j.cell.2020.04.031 Zimmermann ...coronaviruses and enable the virus to enter host cells. To do this, they injected the spike protein from...camelid antibodies that bind to the spike proteins in cell culture, and inhibit these viruses.  But llama ...
  6. Year of the Camelid: Antibody Style

    Type
    Blog Post
    Published
    May 9, 2024, 1:15 p.m.
    ...and a source of sdAbs (Figure 2) (Xu, et al., 2021).      Figure 2: Genetically modified mice offer... from camelid mice and llamas neutralize SARS-CoV-2 variants. Nature 595:278–282. https://doi.org/10.1038...antigens in living cells or tissues. sdAbs can also be used to manipulate cellular functions, like in ...sdAbs over conventional antibodies include:  Excellent tissue penetration, thanks to their small size...
  7. 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...homology-directed repair (HDR) pathway which occurs in cells at low frequencies and relies on the efficient delivery...Later the resultant U-G pair is either repaired by cellular mismatch repair machinery making an original C-G...
  8. Early Career Researcher Toolbox: Social Media for Scientists

    Type
    Blog Post
    Published
    Dec. 11, 2018, 12:46 p.m.
    ...scientists are using social media professionally, and 2) I needed to start using Twitter. Sharing Chemistry...but my consistent writing for the Addgene blog (~1-2 blog posts per month) and use of Twitter and LinkedIn...PhD 👩🏾‍🔬💜 (@ThePurplePage) February 13, 2014 2. "The Scientist's Top 10 Guide to Twitter" blog post...you social media can positively impact your career, 2) given you tips for using various social media platforms...Science Communication” at the American Society for Cell Biology (ASCB) 2018 Conference. I don’t exactly ...
  9. Truncated gRNAs for Regulating Gene Expression

    Type
    Blog Post
    Published
    Jan. 10, 2017, 3:37 p.m.
    ...the absence of genome editing (Fig. 2 and 3) (5, 3). Figure 2: Gene activation with nuclease-competent...shown to exhibit more limited activity than SpCas9 (2). In many cases this is due both to lower relative...PMID: 24076762. PubMed Central PMCID: PMC3844869. 2. Chari, Raj, et al. "Unraveling CRISPR-Cas9 genome... genetic loci within a single cell. One might imagine transfecting cells with both the nuclease-positive...nuclease-competent Cas9, obviating the need to generate new cell lines or transgenic animals expressing dCas9 as ...reliance on orthogonal Cas9 species. Within a single cell, full-length guides targeting one set of genetic...knockin mice for genome editing and cancer modeling." Cell 159.2 (2014): 440-455. PubMed PMID: 25263330. PubMed...
  10. Lentiviral Vector Uses and Overview

    Type
    Blog Post
    Published
    May 19, 2016, 2:30 p.m.
    ...create the 2nd-generation lentiviral system (Figure 2). The HIV genes that do remain are very important ...1996 Apr 12;272(5259):263-7. PubMed PMID: 8602510. 2. A third-generation lentivirus vector with a conditional...CH, Humeau LM, Rebello T. J Gene Med. 2013 Feb;15(2):78-82. PubMed PMID: 23322669. 6. Genetic treatment... Banasik MB, McCray PB Jr. Gene Ther. 2010 Feb;17(2):150-7. PubMed PMID: 19847206. Additional Resources... of cell types, so they’re ideal for work with primary cells or other difficult-to-transfect cells. Lentiviral...dividing cells. Another type of vector, based on adenovirus, could infect non-dividing cells, but without...ability to transduce both dividing and non-dividing cells. Lentiviral vectors are the vector of choice for...
  11. Tetbow: Bright Multicolor Labeling for Neuronal Tracing

    Type
    Blog Post
    Published
    Jan. 24, 2019, 2:24 p.m.
    ...when each of the XFP genes is introduced at ~2 copies per cell per color, following a Poisson distribution...- The XFP genes have to be introduced at ~2 copies per cell per color to achieve the highest color variations...(prepared with Addgene #104110 - #104112) (Figure 2). We’ve also created constructs with containing chemical...imaging with single-cell resolution using chemical cocktails and computational analysis." Cell 157.3 (2014):... optimal expression of XFPs. Any longer and the cells may start to show morphological abnormalities due... wait too long, as too much XFP is toxic to the cells. Inadequate expression levels of XFPs - Reduce the...video below depicting dendrite wiring of mitral cells.   Many thanks to our guest bloggers Richi Sakaguchi...
  12. Optogenetics + CRISPR, Using Light to Control Genome Editing

    Type
    Blog Post
    Published
    Sept. 3, 2020, 12:15 p.m.
    ...the light-inducible heterodimerizing cryptochrome 2 (CRY2) and calcium and integrin-binding protein 1 ...inactive, dead Cas9 protein (dCas9) fused to CIB1; and 2) the activator - the CRY2 photolyase homology region... fused to both the N- and C-termini of dCas9; and 2) CRY2FL-VP64, a fusion of full-length CRY2 and the...researchers saw an 11-fold increase in mRNA levels after 2 hr and a 400-fold increase after 30 hr. The system...authors fragmented Cas9 into N-terminal (residues 2-713, N713) and C-terminal (residues 714-1368, C714...nMagC714 instead of nMagHigh1-C714, generating paCas9-2. This change did not significantly alter the system...prior work, the Sato lab also showed that the paCas9-2 system could be spatially controlled and reversibly...
  13. Mouse Modeling, Part 2: Breeding and Crossing Mice

    Type
    Blog Post
    Published
    Aug. 6, 2019, 12:55 p.m.
    ...detect your targeting vector or gene of interest. 2. Breed your parental mice to generate F1 Once you’...strain, the promoter being used should be tested in cell lines to determine how it impacts the expression...interest. Cre may be expressed globally (in every cell of the mouse) or in a tissue-specific manner (with...
  14. Tips for a 1st time AAV user (by a Rookie AAV user)

    Type
    Blog Post
    Published
    Oct. 23, 2018, 11:49 a.m.
    ...then packaged into AAV’s protein shell, or capsid; 2) the pHelper plasmid which expresses adenovirus genes...takes ~3 hours to complete: 1 hours hands-on time and 2 hours for the qPCR run and data analysis. Refer to...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...packaging AAV is transfecting HEK293 cells with AAV packaging plasmids. The cells need three different plasmids...precipitation. Instead of sonicating the cell pellet, I lyse the cells with this AAV lysis buffer and freeze...bath to release the virus particles from the cells. Cell lysates are then treated with benzonase immediately...
  15. Viral Production at Addgene

    Type
    Blog Post
    Published
    Oct. 24, 2023, 1:15 p.m.
    ...digital PCR. Human Gene Therapy Methods, 25(2), Article 2. https://doi.org/10.1089/hgtb.2013.131 Wang,...maps section for images).     Figure 2: AAV Pro cells were transduced with either pAAV-Ef1a-mCherry-IRES-Cre...Digital PCR Method. Human Gene Therapy Methods, 29(2), 96–103. https://doi.org/10.1089/hgtb.2017.198   ... preparations are added to cells in culture. Three to five days later, cell cultures are inspected for...a new vial of early passage cells. Approximately two weeks post-thaw, cell culture supernatant is tested... (55634-AAVrg) alone at 1.7E6 viral genomes (vg)/cell, pAAV-CAG-FLEX-rc [Jaws-KGC-GFP-ER2] (Addgene 84445...preparations ("-LV” catalog items) are produced in 293T cells using the 2nd generation psPAX2 and pMD2.G packaging...
  16. Hot Plasmids: Spring 2025

    Type
    Blog Post
    Published
    June 3, 2025, 1:15 p.m.
    ...imaging and loose-seal, cell-attached recordings in primary visual cortex (V1) layer 2/3 (L2/3). B) Fluorescence...protocols for viral generation and stable cell line creation (Figure 2). Looking for more? Explore our empty...a protein core, 2–4 glycosaminoglycans (GAG), and are (typically) tethered to the cell surface by a GPI-anchor... Lentiviral backbone plasmids here! Figure 2: Addgene cloned EGFP into pAG Lenti CMV N-HA Puro ...either the optogenetic activator channelrhodopsin-2 or fluorescent reporter dTomato under the control ...PV-positive cells out of all BiPVe3-dTom cells. C) Confocal stack of a biocytin-filled cell expressing ...particles in HEK293T cells with pMD2.G (Addgene #12259) and psPAX2 (Addgene #12260). HeLa cells were infected...
  17. AAVs in Retinal Gene Therapy

    Type
    Blog Post
    Published
    July 31, 2018, 12:55 p.m.
    ...therapy had fallen - plummeted really -  from grace 2 years prior with the death of Jesse Gelsinger in an... the whole field to a grinding stop and only now, 2 decades later, is it finally back in the limelight...the other hand, have broad tropism in the eye. AAV-2, the first identified serotype and the one used in...reading 1. FDA approves gene therapy for blindness 2. Gene Therapy emerges from disgrace to be the next...expression in non-dividing cells because they remain in episomal form in the cell’s nucleus. But since nothing...hope are many more clinical successes for gene (and cell) therapies. One may wonder why the first AAV-based... providing long-term gene expression in retinal cells - AAV - were becoming available. At the same time...
  18. DNA Purification Without a Kit

    Type
    Blog Post
    Published
    Feb. 11, 2020, 2:15 p.m.
    ...level of sensitivity. Figure 2: Steps to purify DNA using a cellulose dipstick. Image: Zou et al., 2018...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...Academy of Sciences of the United States of America, 76 2, 615-9 . https://doi.org/10.1073/pnas.76.2.615  Zhou...broken out of cells with a solution of salts, detergent, and ball bearings. Then a cellulose dipstick is... kits and typically follow the same principles: cells are lysed, RNAs and proteins are removed to leave... could be digested with restriction enzymes.  Cellulose nucleic acid purification Starting material: plant...
  19. Fluorescent Proteins 101: Aptamer Fluorophores

    Type
    Blog Post
    Published
    April 11, 2017, 2:30 p.m.
    ... to DFHBI in the presence of that metabolite (Fig.2). Spinach eventually evolved into Spinach2, a more...PMID: 25713381. PubMed Central PMCID: PMC4364232. 2. Baker, Monya. “RNA imaging in situ”. Nature Methods...emerging environmental pollutants.” Front Chem. 2014; 2: 41. PubMed PMID: 25019067. PubMed Central PMCID: ...biosensors.” TrAC Trends in Analytical Chemistry 27(2):108-117 · February 2008. 11. Svensen, Nina and Jaffrey..., peptides, amino acids, drugs, metal ions, and cells (even pathogenic bacteria). That range is possible... over half a century; the Addgene blog has an excellent primer and tips from experts on FRET techniques... combination of SELEX and fluorescence-activated cell sorting (FACS) of E. coli transformed with aptamer...
  20. 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... between Cas9 (which causes the breaks) and host cell DNA repair factors (which repair those breaks) makes...example, correcting the allele that causes sickle cell anemia. However, HDR occurs much less frequently...a structure could drive sequence replacement in cells. Targeting three dCas9 molecules to a precisely ...functional Cas9 protein and the targeting guide RNA into cells by electroporation. Results from our lab and others...Highly efficient RNA-guided genome editing in human cells via delivery of purified Cas9 ribonucleoproteins...
  21. The Developmental Studies Hybridoma Bank: Over 25 Years of Antibody Sharing

    Type
    Blog Post
    Published
    March 10, 2015, 2:25 p.m.
    ...human transcription factors such as PAX7, PAX6, AP-2 alpha and ISLET-1. In addition, we distribute monoclonal... example through the use of less toxic adjuvants; 2) generating complex antibody chips that allow assessment...produced by a single B cell. To create a monoclonal antibody cell line, myeloma cells are fused with activated...activated B cells from the spleen of mice injected with the antigen of interest. The immortalized cells, called...distributing over 3,000 antibodies and associated hybridoma cell lines. The DSHB was created by the National Institute... individually isolated and expanded. The clonal cells are screened to identify hybridoma lines, each producing...
  22. Negative Can Be Positive: Open AAV Data with Addgene

    Type
    Blog Post
    Published
    Sept. 6, 2022, 1:15 p.m.
    ...indicated they wanted to see more negative data (Figure 2.) At the same time, when scientists who support open...is not only housed, but encouraged.    Fig. 2: Results from a survey conducted by Addgene in 2021...detailed methods and image descriptions, a minimum n = 2, and well labeled high- and low-magnification images...gene therapy trials. Human Gene Therapy Methods, 26(2), 71–76. https://doi.org/10.1089/hgtb.2015.040 Initiative...What works well in one cell or neuron type may not work well for a neighboring cell type, even within the...options while AAV8 (82%) and AAV9 (84%) were both excellent at infecting our target neurons (Figure 1). However... conditions (3,5,8), injection titers (1,2), and cell types used for packaging viral particles (6), can...
  23. Who Gives a Tweet? 9 Facts About Scientists on Twitter

    Type
    Blog Post
    Published
    June 26, 2017, 1:31 p.m.
    ...Occupational Classification System  and Wikipedia. 2. Social and computer scientists are overrepresented...international Twitter users were included in the dataset; 2) users not part of a scientific Twitter list were ...scientists on Twitter are male and 40% are female Figure 2. Gender Ratio of Scientists on Twitter. 60% of scientist...tweeted by biologists were: Nature, Sciencemag, Wiley, Cell and Scientific American Figure 4: Top Scientific...
  24. IBEX Knowledge-Base: A Data Resource for Multiplex Tissue Imaging

    Type
    Blog Post
    Published
    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...approach for deep phenotyping and spatial analysis of cells in complex tissues. Proceedings of the National ...
  25. 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...the next step is to transform competent E. coli cells and select the positive clones. The entry clone ... expression of the human KRAS gene in mammalian cells. STEP 1: Generate an Entry Clone There are a few...ccdB gene. Since the ccdB product is toxic to the cell, Gateway cloning efficiency can reach >99%. ...
  26. The Importance of High Titer for AAV Transductions

    Type
    Blog Post
    Published
    March 1, 2018, 2:11 p.m.
    ...drastically with lower titers. As you can see in figure 2, the expression from the 5x1011 titer was essentially...roughly 6-fold increase in expression [3, Figure 2]. Note how expression increases exponentially with an increase...international 61.1 (2002): S9-S15. PubMed PMID: 11841606. 2. Schultz BR, Chamberlain JS. Recombinant Adeno-associated...Making contact with a cell Although an individual AAV particle’s ability to infect a cell is dependent on its...construction and the cell it’s infecting, getting these particles to infect cells is also very titer-dependent... particle to infect a cell, it has to come into physical contact with that cell. Since there is a limited...of surface area on each cell, the way to get more AAV in contact with the cell is to increase the AAV ...
  27. Simplify Cloning with in vivo Assembly

    Type
    Blog Post
    Published
    Oct. 18, 2018, 12:37 p.m.
    ...ultracompetent (109 CFU/μg) cells. Primer design Using specific primer design (Figure 2), IVA cloning can be...procedure to be performed using a simple two-step, 2 hr protocol prior to transformation (Figure 1). As... 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...transformation efficiency of the strain: when asking the cell to perform multiple recombination events, all linear...linear fragments need to get into the same cell. For simple cloning requiring just one or two recombination...recombination events, homemade competent cells of 107 CFU/μg are perfectly fine, yet performing multiple modifications...
  28. Predicting Adverse Reactions to Monoclonal Antibody Drugs

    Type
    Blog Post
    Published
    Feb. 13, 2024, 2:15 p.m.
    ...various components of the immune system. Figure 2: In-vitro models for immunogenicity prediction of ...drug reaction. This system would somewhat act like a 2-step verification. All approaches have their own limitations...Future Enhancements. Frontiers in drug discovery, 2, 952326. https://doi.org/10.3389/fddsv.2022.952326Joubert...epitopes likely to be presented by T cells to elicit an immune response. T cell epitopes are found in either ...that take place within an antigen-presenting cell like a T cell. It is also not yet possible for these algorithms...traditional 2D assays with immune cell lines or peripheral blood mononuclear cells (PBMC) in 3D models of the...CD4+ or CD8+ T-cells or monocytes. PBMCs can be further differentiated into dentritic cells or macrophages...
  29. Twenty Years of Addgene Sharing: CRISPR

    Type
    Blog Post
    Published
    April 18, 2024, 1:15 p.m.
    ... were depositing and requesting each year (Figure 2). We did a similar analysis with CRISPR pooled libraries...different categories (Figure 2C). Note that in Figure 2, the numbers on the X axis refer to distribution and...rather than a cumulative total.    Figure 2: Addgene CRISPR deposit and distribution by function...rapid adoption of new tools, illustrated in Figure 2, and the longevity of tools seen in Figure 3, indicates...As we celebrate twenty years at Addgene, we are sharing stories of our repository’s positive impact on... Sharing this story is a truly special way to celebrate our twentieth anniversary in 2024, and it’s all...
  30. CRISPR 101: Cytosine Transversion Editors

    Type
    Blog Post
    Published
    March 25, 2025, 1:15 p.m.
    ...translocation. Nature Cell Biology, 26(2), 294–304. https://doi.org/10.1038/s41556-023-01342-2 Koblan, L. W.,...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...By taking advantage of repair pathways within the cell — in some cases, the same repair pathways that were...adenosine (A) to inosine (I, treated as G by the cell). Surprisingly, the team noticed that this editor...
  31. Antibodies 101: ChIP

    Type
    Blog Post
    Published
    March 10, 2022, 3:25 p.m.
    ...everything just right!  Fig. 2: Goldilocks is actually celebrating a successful ChIP experiment! Image...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... Process ChIP can be done for either tissues or cells. The process is very similar for both, though tissue...fragmenting the DNA, spin down the samples to remove cell debris, which will collect in a pellet. The supernatant..., these are mostly fairly standard molecular and cell biology techniques. What’s all the fuss? Well, ChIP...will also have to be optimized for both tissue or cell type, amount of protein, and desired fragment length...
  32. A Practical Guide to Optimizing AAV DIO and FLEx Vector Expression

    Type
    Blog Post
    Published
    Nov. 2, 2021, 1:15 p.m.
    ...Capsids from Serotypes 1, 2, and 5 Display Differential Efficiency and Cell Tropism after Delivery to ...one of lox2272 sites will now be sandwiched between 2 loxp sites and is excised by Cre (Figure 1). This ...flank the transgenes (non-homologous pairs) (Figure 2.). They found that almost all off-target expression...exercise caution when using them.    Figure 2. Schematic diagram showing the mechanism of spontaneous... Tropism and Axonal Transport of AAV Serotypes 1, 2, 5, 6, 8 and 9 in the Mouse Brain. PLoS ONE 8:e76310...specific cell type rely on transgenic models that express recombinases like Cre or Flp in their cells of interest...entry into the cell (Dudek, AM. 2018).  If the serotype you are using transduces cells that you are not...
  33. Viral Vectors 101: AAV Serotypes and Tissue Tropism

    Type
    Blog Post
    Published
    Jan. 16, 2025, 3:42 p.m.
    ...proteoglycan (HSPG)3 AAV receptor (not strictly required)2 Human fibroblast growth factor receptor 1 (FGFR1... AAV2, so they are formally called rAAV2/1, rAAV2/2, and so on, although we often use abbreviated nomenclature...suggest these serotypes as a good place to start. Table 2: AAV tissue tropism for mice in vivo. To target... tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain. PloS One, 8(9),...Retrograde Access to Projection Neurons. Neuron, 92(2), 372–382. https://doi.org/10.1016/j.neuron.2016.09.021...particle sneaks its way into cells. Generally, AAV serotypes have a primary cellular receptor and sometimes ...transduction efficiency, and is an excellent choice for targeting cardiac cells (Bish et al., 2008). It can ...
  34. Advanced Uses of Cre-lox and Flp-FRT - A Neuroscientist’s View

    Type
    Blog Post
    Published
    Oct. 19, 2017, 1:54 p.m.
    .... “A FLEX Switch Targets Channelrhodopsin-2 to Multiple Cell Types for Imaging and Long-Range Circuit ...FLP and Cre for additional control   Figure 2: Expression of a morphological marker (eYFP) and synaptic...PMID: 18614669. PubMed Central PMCID: PMC2593125. 2. Buchholz, F, P O Angrand, and A. Francis Stewart....The FLP Recombinase of the Saccharomyces Cerevisiae 2 Micron Plasmid Attaches Covalently to DNA via a Phosphotyrosyl...specific cell types (populations) within neuronal networks in living animals. To accomplish such cell specific...individual cells. With this technique, a Neuroscientist can see the full dendritic arbor of a single cell with...Cre-mediated possibilities for site specific (and often cell type specific) control of DNA recombination and ...
  35. 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...genes known to be essential for cell growth. Together, this excellent work highlights the importance of...fluorescence-activated cell sorting (FACS). This is not possible in plants outside of limited, single cell protoplast...exquisitely and robustly self-organize at the cellular and multicellular scale.     References Bezanilla M, Perroud...can be found at Addgene that could serve as an excellent start (#22988, #137884). Both vectors allow the...
  36. Light Sheet Fluorescence Microscopy

    Type
    Blog Post
    Published
    July 16, 2015, 2:30 p.m.
    ...Carballosa, et al, (2015) eNeuro, March/April 2015, 2(2) e0001-15.2015. Pubmed. Resources: http://openspim.org...orthogonal-plane fluorescence optical sectioning (OPFOS) (2). Arne Voie, David Burns and Francis Spelman focused...in LSFM. In LSFM the laser light sheet, typically 2-6  microns, illuminates only one thin plane of the...transparent are enabling microscopes to visualize the cellular architecture of whole tissues in 3D with unprecedented... Weber, M. Mickoleit, J. Huisken. (2014) Methods Cell Biol.123, 193-215. Pubmed. W. Spalteholz. (1914)...
  37. Fluorescent CRISPR Reporters: SRIRACCHA and GEmCherry2

    Type
    Blog Post
    Published
    May 26, 2020, 1:15 p.m.
    ...Madison lab found that H2B-GFP expressing cells exhibited a 2-4 fold increase in the number of endogenous...Denham lab made several other small changes creating 2 other versions but these did not surpass GEmCherry2...fluorescence and in-frame fluorescence.  Figure 2: The GEmCherry reporter. Image from Højland Knudsen...introduced the reporter into the cells, you’re ready to edit. These cells are then transfected with several... up, all successfully transfected cells will express RFP while cells containing the reporter gene that...using the RFP:GFP ratio, edited cells can be sorted from unedited cells. In an experiment that targeted...Activity. Frontiers in Cell and Developmental Biology 6: . https://doi.org/10.3389/fcell.2018.00054 Sander...
  38. Important Considerations in Optogenetics Behavioral Experiments

    Type
    Blog Post
    Published
    Oct. 1, 2015, 2:30 p.m.
    ... will repeatedly nose-poke at the active hole [1, 2].    Place preference/place aversion also models reinforcement...spend most of its times in the opposite chamber) [2]. Laser activation is usually controlled automatically...two different ways 1) your hypothesis is wrong or 2) there is some problem with the technical implementation...PMID: 21716290. Pubmed Central PMCID: PMC3775282. 2. McDevitt, Ross A., et al. "Serotonergic versus nonserotonergic...optogenetics, ICSS can now be done with neuronal cell-type and temporal precision. In ICSS, a test chamber... remote contextual memories. This study is an excellent example in which the authors started with a brain... research. Derek P. Simon received his PhD in Cellular and Molecular Biology from the University of Michigan...
  39. Quick Guide to Working with Drosophila Part 3: Genome Engineering in Flies

    Type
    Blog Post
    Published
    July 28, 2017, 1:30 p.m.
    ...are many docking sites available for integration. 2. How soon would you like your flies ready for use?...beautiful immunofluorescent images like in this paper (2). Metabolic assays such as Seahorse can be employed...PMID: 16547094. PubMed Central PMCID: PMC1526508. 2. H. Jiang,  et al. Cytokine/Jak/Stat signaling mediates...Drosophila cell line, I’ve studied a transcription factor important for T cell differentiation (a cell type ...regeneration and homeostasis in the Drosophila midgut. Cell. 137, 1343–55 (2009). PubMed PMID: 19563763. PubMed...et al. Digoxin and its derivatives suppress TH17 cell differentiation by antagonizing RORγt activity. ...
  40. Antibodies 101: Flow Cytometry

    Type
    Blog Post
    Published
    July 20, 2021, 1:15 p.m.
    ...termed fluorescence activated cell sorting or FACS (2). By analyzing single cells instead of the population...populations (Figure 2). An immunologist who studies B cells, might then gate the B cell population and create..., these cell types will separate into distinct populations on a FSC versus SSC plot (Figure 2).  A user... Figure 2: Due to differences in their size and complexity, cells from a whole blood sample will...expression. A routine flow cytometry experiment uses 2 or 3 different fluorescent colors each measuring a...plot of CD3 (T cell marker) versus CD19 (B cell marker) to separate the B cell and T cell into distinct...separate the B cell population into progenitor B cells, immature B cells, plasma cells or others.   ...
  41. 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, ...product, the transformation may not result in any cells, or all the colonies screened might not contain ...verify the strain and the efficacy of your competent cells (when they get old, they lose competency). If all... look at your experimental design. Full lawn of cells. The antibiotic in your plate might not work. Check...acknowledged in hundreds of publications including Cell, Nature, and other journals.   Paolo Colombi is ...
  42. Live and Let Dye: Self-Labeling Protein Tags

    Type
    Blog Post
    Published
    April 16, 2024, 1:15 p.m.
    ...for Multiprotein Labeling in Living Cells. Chemistry & Biology, 15(2), 128–136. https://doi.org/10.1016...super-resolution or single-molecule techniques.   Figure 2: Two-color super-resolution imaging of ER and mitochondria...stimulated emission depletion (STED) nanoscopy. Scale bar, 2 μm. Inset shows comparison with standard confocal ...enables applications like multi-color imaging (Figure 2). If you’re working with purified proteins in vitro...conjugates: A flexible chemical tag. Nature Methods, 2(4), Article 4. https://doi.org/10.1038/nmeth749 Strebinger...Bewersdorf, J. (2016). Two-colour live-cell nanoscale imaging of intracellular targets. Nature Communications,...opening up new applications.   Figure 1: Live-cell labeling strategies. The green structure represents...
  43. Plasmids 101: TOPO Cloning

    Type
    Blog Post
    Published
    Oct. 27, 2016, 2:30 p.m.
    ... the two DNA strands and releasing topoisomerase (2).  These days commercially available TOPO kits provide...Taq polymerase using your favorite PCR protocol.  2. Set Up TOPO Cloning Reaction: Mix together the PCR...PubMed PMID: 1658796. PubMed Central PMCID: PMC52876. 2. Novel approach to molecular cloning and polynucleotide... Transform TOPO Cloning Reaction into Competent Cells: You can use your standard lab protocol for this...
  44. Addgene’s Newest Way to Speed Your Research: The Cloning Grade DNA Service

    Type
    Blog Post
    Published
    July 28, 2020, 1:15 p.m.
    ... be directly used in the research on the SARS-CoV-2. Nine of the overall plasmid selection will be open... cloning grade DNA beta project We will ship you  2 µg of DNA in 20 µl of Tris buffer suitable for molecular...service to further contribute to our mission to “accelerate research and discovery.” Here are the details...
  45. Hot Plasmids April 2018 - Protein Degradation, Nanoscopy, FIRE-Cas9, and Yeast Expression Tools

    Type
    Blog Post
    Published
    April 23, 2018, 2 p.m.
    ...ddifferent cell types, including difficult-to-manipulate primary cells, achieving knockdown within 1-2 hr of...factor 1 controls expression of transcription factor 2, which directly controls expression of a reporter ...modulating the induction of transcription factors 1 and 2. See Aranda-Díaz et al. for more information. The ...stable cell lines overexpressing TRIM21, finding that TRIM21 overexpression did not affect cell proliferation...electroporated cells re-adhered to the culture plate within 4 hr of treatment. In some primary cell lines, endogenous...proliferation. These cells also did not contain changes in expression of TRIM21-associated genes, indicating...multiple methods for TRIM-Away delivery. For small cell populations, co-microinjection of TRIM21 protein...
  46. Viral Vectors 101: Calcium Sensors

    Type
    Blog Post
    Published
    Aug. 10, 2023, 1 p.m.
    ...illumination with violet light and (2) exposure to increased intracellular calcium. It has been applied to...calcium biosensor, so that the (1) binding of calcium, (2) allosteric rearrangements of the sensor, and (3) ...dynamics in vivo. Neuroscience Research. 2021 Aug 1;169:2-8. Suzuki J, Kanemaru K, Iino M. Genetically encoded... defined population of cells (e.g., a neuron subtype) and specific subcellular compartments for measurements...calcium concentrations and transients in living cells and organisms. Unlike chemical indicators, these...Localization The calcium concentrations in different subcellular compartments can vary greatly. Additionally, ...neuron-specific expression (hSyn promoter) and pan-mammalian cell expression (CAG promoter). An improved version named...
  47. Pairing CombiGEM and CRISPR for Combinatorial Genetic Screening

    Type
    Blog Post
    Published
    April 12, 2016, 2:30 p.m.
    ...CombiGEM lentiviral vector backbone pAWp12 (Figure 2). Cloning from the pAWp28 storage vector to the pAWp12... before beginning your experiments. Figure 2: Strategy for assembling barcoded combinatorial gRNA...PMID: 25114216. PubMed Central PMCID: PMC4151723. 2. Doench, John G., et al. "Optimized sgRNA design to...genes essential for West-Nile-virus-induced cell death." Cell reports 12.4 (2015): 673-683. PubMed PMID:... (and multiple) genetic perturbations in single cells. Methods to scale up multiplexed CRISPR systems ... build and constantly improve gRNA libraries, excellent resources with effective gRNAs are publicly available...perturbations and applications in functional genomics, cell reprogramming, and beyond. For further details, ...
  48. Plasmids 101: CcdB - The Toxic Key to Efficient Cloning

    Type
    Blog Post
    Published
    Dec. 8, 2016, 3:30 p.m.
    ...CcdB.” Biotechniques. 1996 Aug;21(2):320-3. PubMed PMID: 8862819. 2. Bahassi, EM., et al. “F plasmid CcdB... desired insert should not grow.   Figure 2: Image from http://teachline.ls.huji.ac.il/72682/tutorials... protein (CcdA) that protects the cell against the toxic CcdB. Cells that lose ccdA through the loss of...disrupted allowing cells expressing the recombinant plasmid to propagate. Any cells that contained non-recombinant...which is responsible for plasmid maintenance during cell division. ccdB codes for the toxic protein (CcdB...broken double stranded DNA and ultimately causing cell death. ccdA, another gene found in the ccd operon...Gateway takes advantage of the same principle that cells will not propagate while expressing the gene. Briefly...
  49. Evolution of Brainbow: Using Cre-lox for Multicolor Labeling of Neurons

    Type
    Blog Post
    Published
    April 24, 2015, 2:39 p.m.
    ...Brainbow mouse neural labeling system. Brainbow-1 and -2 have been further refined to create Brainbow 3.2. ...M-CFP expression; these deletions are defined using 2 loxP variants (only identical loxP sites can mediate... each fluorophore. Third, Brainbow-1 and Brainbow-2 each contained a “default” state; for example, Brainbow...processes not previously visible with Brainbow-1 and -2. The general structure of Brainbow-1.0 is retained... brain, robust single-cell labeling is necessary to distinguish individual cells. The Brainbow-1.0 construct... May 5. PubMed. Zebrabow: multispectral cell labeling for cell tracing and lineage analysis in zebrafish... both of Harvard’s Department of Molecular and Cellular Biology, harnessed these attributes of Cre-lox...
  50. Enhancing CRISPR Targeting Specificity with eSpCas9, SpCas9-HF1, & HypaCas9

    Type
    Blog Post
    Published
    Dec. 16, 2015, 3:30 p.m.
    ... (2,3). Stable strand separation is maintained by 2 sets of interactions : 1. Interactions between the...formed by the Cas9 HNH and RuvC nuclease domains 2. Interactions between the target strand and the gRNA... Find plasmids from this publication at Addgene. 2. Nishimasu, Hiroshi, et al. "Crystal structure of ... the EMX1 locus in human embryonic kidney (HEK) cells, 11 of these initial mutants retained the on-target...off-target activity at multiple genomic locations in HEK cells. Further testing of two of the mutants, SpCas9(K855A... showed that these mutants are not toxic to HEK cells and that similar mutations can improve the specificity... researchers to make precise edits in mammalian cells and may decrease worries about off target effects...
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