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  1. Lighting Up Cell Signaling with Photoswitchable Kinases

    Type
    Blog Post
    Published
    July 25, 2017, 1:20 p.m.
    ...status of MEK1/2 was tracked at 5 minute intervals via Western blot. Phosphorylation of MEK1/2 peaks at just...PubMed PMID: 28232577. Figures 2-4 were modified from this reference. 2. Regot, Sergi, Jacob J. Hughey...Treatment of the cells with a PP1/PP2A inhibitor leads to maintenance of phosphorylated MEK1/2 levels, suggesting...precisely control the timing of kinase activity. 2. Studying negative feedback loops of signaling pathways... studied the negative feedback on endogenous MEK1/2 phosphorylation by creating a short pulse of psRaf1...activity. They did this by exposing psRaf1 to a short 2 minute pulse of 500 nm light (turn on psRaf1) followed...suggesting PP1/PP2A is responsible for this MEK1/2 negative feedback. 3. Studying signaling pathways in...
  2. When is a Monomer not a Monomer? The Top Three Ways Your Favorite Fluorescent Protein Oligomerizes in Cells

    Type
    Blog Post
    Published
    April 19, 2016, 2:30 p.m.
    ...difficult to ignore [1, 2]. 2. Fusion to an obligate dimer or oligomer Several cell proteins normally self-associate.... J Cell Biol, 2003. 163(2): p. 257-69. PubMed PMID: 14581454. PubMed Central PMCID: PMC2173526. 2. Zacharias...Kd is unlikely to form dimers in a cell. The Kd of EGFP is 0.11 mM [2]. Following the simple logic outlined... nature are prone to dimerization (i.e. EGFP) [1, 2] or even form obligate tetramers (i.e. DsRed) [3]....organized smooth endoplasmic reticulum (OSER) whorls. 2)A dimerizing protein of interest fused to a dimerizing... designed to detect resulting in false positives [2, 4]. Solutions to the polymer problem There are some...Citrine) can be monomerized with an A206K mutation [2]. Addgene has many of these constructs and they are...
  3. Giving gRNAs a Facelift - Synthetic and Beyond

    Type
    Blog Post
    Published
    Oct. 20, 2022, 1:15 p.m.
    ...same site, is 2’-fluoro (2’-F), which substitutes a fluorine for the hydroxyl group at the 2’ position. ...most common of these is 2’-O-methylation, where a methyl group is added to the 2’ hydroxyl group of the...them together, for example phosphorothioates with 2’-O-methyl modifications, proved more stability than...generated by introduction of a single photocleavable 2-nitrobenzyl linker in the 20-bp targeting region of...photocleavable gRNAs. Molecular Cell 81, 7, 1553-1565 (2021). https://doi.org/10.1016/j.molcel.2021.02.007 Moroz-Omori...evolved ways to prevent degradation of important cellular RNA molecules with post translational modifications...slightly more efficient and less toxic to mammalian cells (Allen, et al., Frontiers in Genome Editing).  Some...
  4. Starter guide to induced pluripotent stem cells (iPSCs) part 1:  A renaissance in regenerative medicine

    Type
    Blog Post
    Published
    Oct. 30, 2018, 1:04 p.m.
    ... Regenerative Medicine. Acta Naturae, 2010. 2(2): p. 18-28. PubMed PMID: 22649638. PubMed Central PMCID...specialized cell types [2]. We general speak of 4 levels of stem cell potency: Totipotency: When a cell has ...embryonic stem cells (ESCs), which I discuss in detail below [2]. Multipotency: When a cell can differentiate...mammalian development, cells found in the zygote through to the morula stage are totipotent [2-4]. Pluripotency...PubMed Central PMCID: PMC4686367. 2. Jaenisch, R. and R. Young, Stem cells, the molecular circuitry of pluripotency...Pharmacological Sciences, a Cell Press reviews journal. Stem cells are special types of cells that can develop ...pluripotent cells can be thought of as descendants of totipotent cells. An example of pluripotent cells is embryonic...
  5. 3 Tips to Improve HDR Efficiency for CRISPR Editing in Human Cells

    Type
    Blog Post
    Published
    Sept. 5, 2017, 1:58 p.m.
    ...into account that HDR is rare, usually 2-5% of the edited cells in our hands, these combined pitfalls ...hundred clones to find the right one Step 2 – Edit the cells a second time using a repair template that...improving editing accuracy by preventing re-editing and (2) optimizing “cut-to-mutation distance”. Furthermore...Additional CRISPR Resources on Addgene's CRISPR Guide Page 2. Optimizing "cut-to-mutation distance"  Even though... wisely (and let them cut close).   Figure 2: Relationship between cut site to mutation distance...PMID: 23287718. PubMed Central PMCID: PMC3795411. 2. Mali, Prashant, et al. "RNA-guided human genome engineering...sequence change the cell must undergo homology-directed repair (HDR), a distinct cellular DNA repair pathway...
  6. Fluorescent Proteins 101: Visualizing Subcellular Structures & Organelles

    Type
    Blog Post
    Published
    June 22, 2017, 2:30 p.m.
    ...ImageJ plugins JACoP and Coloc 2, BioImageXD, and customized CellProfiler pipelines. Image analysis software...optimized for diverse cellular environments. Since colocalization relies upon the detection of 2 independent fluorescent...Markers of Subcellular Localization Poster here! References 1. Allen Institute Plasmid Pages 2. Cooper ... to the lysosome where they are finally degraded (2, 3). Once you've created your fusion protein, it's...colocalization analysis example is given in Figure 2 (adapted from 4) - Dunn et al. 2011 provides an in-depth...organs, cells comprise compartments and structures, called organelles. Take a sneak peak inside a cell with...vesicles via the secretory pathway to their subcellular or extracellular destination. At the end of their life...
  7. Synthetic promoter AAVs for cell-type specific expression in retinal cells

    Type
    Blog Post
    Published
    March 12, 2020, 1:15 p.m.
    ...the start codon of retinal cell-type specific genes from mice. Strategy #2 (ProB): Create promoters using...horizontal cells transduced by both AAVs would express Cre-mCherry and GFP.   Figure 2: Synthetic...doi.org/10.1038/s41593-019-0431-2  Neff, E.P. An AAV library for retinal cell expression in mouse, macaque... horizontal cells, and Cre-dependent-GFP expresses in horizontal cells and ganglion cells, only the horizontal... in retinal cells. To do this, the group developed a new strategy for finding retinal cell-type specific...and high cell-type specificity.  Strategy #3 (ProC): Create promoters by repeating mouse cell type specific... to test for cell type-specific expression of GFP. Half (113) expressed in retinal cells four weeks post-injection...
  8. Cellosaurus: A Cell Line Information Database

    Type
    Blog Post
    Published
    Feb. 21, 2023, 2:15 p.m.
    ...can browse entries by cell line groups, such as their vaccine production, SARS-CoV-2 research, or adenovirus...Knowledge Resource. J Biomol Tech. 2018; 29(2): 25-38....in which the cell line was described. Using Cellosaurus Cellosaurus is searchable by cell line name (recommended...resource called Cellosaurus, a growing cell line information database describing nearly 145,000 cell lines. Cellosaurus... Cellosaurus Cellosaurus seeks to identify and describe all cell lines used in research, using four methods... related cell lines when annotating a cell line Community submissions via email: cellosaurus@sib.swiss...with cell line catalogs and collections. Importantly, Cellosaurus also identifies problematic cell lines...
  9. CRISPR 101: Making a Knock-In Cell Line

    Type
    Blog Post
    Published
    Dec. 22, 2022, 2:15 p.m.
    ...Disable the other repair mechanisms Mammalian cells have 2 primary repair mechanisms besides HR - Non-homologous... However, if you have a larger knock-in (200 bp – 2 kb), a dsDNA donor will need to be used due to synthesis...accidentally change your protein of interest.   Fig. 2: Stop re-cutting with PAM and guide RNA disrupting.... Com., 8(2024), (2017). 10.1038/s41467-017-01836-2 Charpentier, M., Khedher, A. H. Y., Menerot, S., Brion...varying across cell types. Variance can be caused by cell cycle rates; rapidly diving cells will have higher... of your cells. Enrich S-phase cells HR operates predominantly in S and G2 phase of the cell cycle, when...HDR events, ensure cells are actively cycling through the cell cycle stages. If cells are overly confluent...
  10. Opto-Nanobodies: Using Light to Manipulate Cell Signaling and Protein Purification

    Type
    Blog Post
    Published
    Nov. 19, 2019, 2:08 p.m.
    ...non-specific proteins, and then elute YFP.  Option #2: Opto-Nanobodies (OptoNBs) purification You skip adding...blue lights. Which option do you choose?  Option #2 may sound like fiction, but light-controlled protein...experiments.  AsLOV2 Inertion Site mCherry #1 mCherry #2 GFP Loop 1 dark-induced dark-induced dark-induced...OptoNBs to control cell signaling The second application for OptoNBs takes us into cells: light-based control... regulation of endogenous signaling activity in cells.  Let’s shed some light on the key components of...their use for protein purification and controlling cell signaling. Key components of OptoNBs OptoNBs have...can bind, it co-localizes with its target at the cell membrane and when the OptoNB can’t bind, it localizes...
  11. Photosensitizer Induced Cell Ablation with FAP-TAP MG-2I-dL5**

    Type
    Blog Post
    Published
    Sept. 19, 2017, 1:20 p.m.
    ... post treatment (see figure 2). Induced cell death was confirmed by TUNEL staining.  The video below shows...fluorogen activating protein - dL5** in this case), and 2) a fluorogen (the TAP - targeted and activated photosensitizer...PMID: 26808669. PubMed Central PMCID: PMC4916159. 2. Jacobson, K., Rajfur, Z., Vitriol, E., & Hahn, K....HEK293 cell culture and in live zebrafish. For cell culture experiments, only dL5**-expressing cells treated...inactivate target proteins or cells while having little effect on neighboring cells. The photosensitizer used...Here Light-induced cell ablation with MG-2I-dL5** He et al tested out light-induced cell ablation with MG...effective killing of dL5** cells without death of neighboring bystander wild-type cells.   Zebrafish experiments...
  12. Starter Guide to induced Pluripotent Stem Cells (iPSCs) Part 2:  Reprogramming and Transdifferentiation

    Type
    Blog Post
    Published
    Nov. 6, 2018, 1:12 p.m.
    ...Induction of Human Germ Cell Fate from Pluripotent Stem Cells. Cell Stem Cell, 2015. 17(2): p. 178-94. PubMed... of human induced pluripotent stem cells. Stem Cell Rev, 2015. 11(2): p. 242-53. PubMed PMID: 25578634...differentiated somatic cell to revert back to a pluripotent stage (iPSC formation) [2, 3]. The iPSCs then...somatic cells via various methods. Some of the more common delivery methods include retrovirus [2], lentivirus...PubMed PMID: 16810240. 2. Takahashi, K., et al., Induction of pluripotent stem cells from adult human fibroblasts...three routes to regeneration. Nat Rev Mol Cell Biol, 2011. 12(2): p. 79-89. PubMed PMID: 21252997. 37. Merrell...differentiation of human ES cells and iPS cells into mature pancreatic insulin-producing cells. Cell Res, 2009. 19(...
  13. Adeno Associated Virus (AAV) for Cell and Gene Therapy

    Type
    Blog Post
    Published
    Nov. 7, 2017, 1:59 p.m.
    ...postmitotic, long-lived cell types. AAVs in the clinic Thus far, AAV vectors AAV1, AAV-2, AAV1-AAV2 hybrids...neutralizing antibodies against some AAV types, AAV1, 2, 3 and 5 are thought to be as high as 70% among the... 10.24 (2003): 1999-2004. PubMed PMID: 14566358.  2. Hirsch, M. L., et al. "Self-complementary AAV mediates... do so, their T-cells were grown in vitro, their mutations corrected, and the T-cells were transferred...functioning T cell repertoire (1). In this example, it was possible to transduce the T-cells outside the...a wide range of cell types including but not limited to muscle, liver, and brain cells. There are a multitude...chain (c) and is characterized by a lack of immune cell development and function. To date, gene therapy ...
  14. Cloning Mammalian Cells with the Agarose Method

    Type
    Blog Post
    Published
    Sept. 7, 2017, 12:17 p.m.
    ...splitting transfected cells into 3 plates at different densities for selection). A 2% agarose solution is...transition from a 48-well cell plate to a 96-well assay plate. We generally freeze at least 2 ampules each of 4...of agarose, which is then overlaid with the firmer 2% agarose gel solution discussed above for picking.... a wide variety of cell lines, from HEK to CHO cells to neural and endocrine cells such as AtT-20, PC12...then handled. Additionally, many cell lines, especially the endocrine cell lines we most commonly work with...specific cell line, and its transfection efficiency. We often trypsinize the transfected cells on the day...increased). For some cells, add a drop of serum to aid in outgrowth. Depending on the cell type, we sometimes...
  15. Production of Virus in Insect Versus Mammalian Cells

    Type
    Blog Post
    Published
    Nov. 5, 2024, 8:32 p.m.
    ...AAV); 8–10 kb (lenti) 38 kb Cells HEK-293T Sf9 Time to collection 2–4 days 5–10 days Purification... R.M. (2002). Insect cells as a factory to produce adeno-associated virus type 2 vectors. Human Gene Therapy...Centrifugation Titration time ~1 day (AAV); ~1 week (lenti) 2–10 days Initial titers Higher Lower Resources...that already do mammalian cell culture. HEK-293T cells are the most common cells used in viral production...versus insect cells for viral production Consideration Mammalian cells Insect cells Viruses AAV ...type of cells that will be used to make the virus. Viruses can be produced in many different cell types,...produced in bacteria cells. However, some viruses can be produced in multiple different cell types, including...
  16. CRISPR Protocol for Genomic Deletions in Mammalian Cell Lines [Video]

    Type
    Blog Post
    Published
    Feb. 18, 2015, 3:09 p.m.
    ...deletions in human cells using zinc finger nucleases. Genome Res. 2010 Jan;20(1):81-89. PubMed. 2. Bauer DE, ...with TALENs, in collaboration with the Porteus lab [2]. With the advent of CRISPR/Cas9, we began to explore...CRISPR plasmids into MEL cells by electroporation, sort your transfected cells via FACS, primer validation...article "Generation of Genomic Deletions in Mammalian Cell Lines via CRISPR/Cas9" from the Journal of Visualized...CRISPR/Cas9 to create genomic deletions in mammalian cell lines. Below Bauer and Canver discuss the motivations...deletions is to produce monoallelic deletion clones. Cells with just a single intact copy at a given locus ...screening by conventional PCR. Biallelically disrupted cells can be easily identified. Even in the case of clones...
  17. Four Factors that Differentiate the Stem Cell Field

    Type
    Blog Post
    Published
    Sept. 28, 2016, 2:35 p.m.
    ... Podcast Interview with Stem Cell Researcher Darrell Kotton 2. Stem cell scientists care about patients...explained that it took 50 people nearly 2 years to create the first stem cell line that could be used in clinical...prevent stem cell lines from becoming the new HeLa cells?), genome engineering and stem cells, and the difficulty...opportunity to see Shinya Yamanaka celebrate the tenth anniversary of his landmark Cell paper showing that it was...generate induced pluripotent stem cells (iPSCs) capable of forming nearly all cell types in the body from otherwise... happening. Stem cells scientists have certainly not lost site of that. 3. Stem cell science is hard, ...otherwise terminally differentiated cells simply by expressing four proteins Oct4, Sox2, Klf4, and cMyc...
  18. Fluorescent Proteins 101: Monitoring Cell Mobility Using Fluorescent Proteins

    Type
    Blog Post
    Published
    Aug. 15, 2017, 1:24 p.m.
    ...the specimen.  2. Fluorescence Activated Cell Sorter (FACs) A machine that sorts cells according to whether...photostability of your fluorescent protein when using 2-photon microscopy as this hasn't been well reported...PMID: 18703742. PubMed Central PMCID: PMC2606057. 2. Chtanova, Tatyana, et al. "Dynamics of neutrophil...labeling T cells, B cells, and antigen presenting cells, scientists have been able to decypher cellular dynamics...tracked by cell sorter giving immunologists the ability to count cells and statistically analyze cell movements...fast T cells could jump from one antigen presenting cell to another. Indeed, we now know that T cells are...2016)? How do dendritic cells migrate to lymph nodes to activate T cells (Celli et al 2008, Kitano et al...
  19. A New Generation of Adenine Base Editors Improves Editing in Primary Human Cells

    Type
    Blog Post
    Published
    May 7, 2020, 1:15 p.m.
    ...NGG-3′ (“N” can be any nucleotide base, followed by 2 guanines). This limits the use of ABEs as DNA sites... in the promoter region of gamma hemoglobin (HGB1/2) leads to continuous expression of fetal hemoglobin...primary human cells  Cell therapy approaches can use base editors to correct mutations in stem cells and return...primary human cell editing, the researchers tested ABE8 in CD34+ hematopoietic stem cells. ABE8 efficiently... In addition to stem cells the authors targeted 6 genes in primary human T cells using 8 selected ABE8s...to edit primary human T cells efficiently makes it a promising tool for T cell therapy development.  Reducing...be introduced into cells as a plasmid or as mRNA constructs. In primary human cells mRNA delivery of ABEs...
  20. pCXLE toolkit: Efficient episomal plasmid-based method to reprogram peripheral blood cells to iPSCs

    Type
    Blog Post
    Published
    Dec. 14, 2017, 2:08 p.m.
    ...PMC5118044. 2. Kim, Y., et al., The Generation of Human Induced Pluripotent Stem Cells from Blood Cells: An Efficient...blood are reprogrammed immediately after collection [2]. PBMCs display unique epigenetic signatures that ...human-induced pluripotent stem cells from cord blood and peripheral blood cells. Stem Cells, 2013. 31(3): p. 458...possible to reprogram differentiated cells into induced pluripotent stem cells (iPSCs) by the addition of reprogramming... somatic cells that are otherwise difficult to obtain. These can then be used to perform cell therapy ...in vitro. Find stem cell plasmids at Addgene Many sources of adult somatic cells have been probed for...Using Serial Plating of Reprogrammed Cells by Centrifugation. Stem Cells Int, 2016. 2016: p. 1329459. PubMed...
  21. Stem Cell Models for Disease & Open Science: Interview with Darrell Kotton

    Type
    Blog Post
    Published
    July 7, 2017, 1:32 p.m.
    ...develop therapies to treat disease in the lung. Chapter 2: Balancing research with medical practice as an MD...engineered cells in therapy. The lungs are difficult, but other tissues like the retina have cell-based therapies...Chapter 9: Using stem cells as in-vitro models of disease. How Darrell is using stem cells from patients to...sharing reagents, cell lines, data, and knowledge without exclusivity. Chapter 11: The Stem Cell Bank (CReM ...the lungs, and, among other projects, using stem cells to develop in vitro models for lung disease. Darrell...what drives him as a praticing physician and stem cell researcher. Darrell's ultimate goal - to develop...means to treat disease through tissue repair, stem cells, gene therapy, and tissue engineering. How the multidisciplinary...
  22. X-CHIME: Context Dependent Germline Knockout in Immune Cells

    Type
    Blog Post
    Published
    Jan. 16, 2024, 6:13 p.m.
    ...), 1668. https://doi.org/10.1038/s41467-019-09656-2 More resources on the Addgene blog CRISPR101: Validating...hematopoietic stem cells with a lentiviral vector containing a gRNA. These transduced stem cells can be implanted...Annotation of genes in immune cells typically involves the creation of germline knockout mice, which ...CRISPR-based systems enable gene knockout in immune cells in a high-throughput manner, but these systems have..., ubiquitous knockout of single genes in immune cells in vivo (LaFleur et al., 2019a and LaFleur et al...many genes have different functions in different cell types, at different times, and in combination with... L-CHIME Knocks out a single gene in defined cell types (lineage-based) pXPR_070 Violet-excited...
  23. Genetically-encoded Sparse Cell Labeling - A SPARC of Innovation

    Type
    Blog Post
    Published
    May 21, 2020, 1:15 p.m.
    ...(I), or sparse (S) labeling of the cell population. Figure 2: Dense (c), intermediate (d), and sparse...single genetically-defined subset of cells. By labeling fewer cells in a population, it’s easier to visualize...non-overlapping cells. While transgenic animals are commonly used to specifically manipulate a cell type of interest...expressed. In cells where the stop cassette remains, the effector is not expressed and the cells are not labeled...sparse labeling of the cell population that expresses SPARC and the fraction of cells that will be labeled... interest in an organism, all cells of that type are affected. Previous tools to overcome this restraint... of the gene construct. A predictable number of cells will express the effector or retain the stop cassette...
  24. A Look Back at One Year of Plasmid Sharing for COVID-19 Research

    Type
    Blog Post
    Published
    July 12, 2021, 1:15 p.m.
    ...SARS-CoV-2 spike pseudotyping, visit the SARS-CoV-2 Pseudotyped Virus collection page. SARS-CoV-2 detection...of SARS-CoV-2 entry and become upregulated during viral infection.  Expression of SARS-CoV-2 viral proteins...pseudotyping The SARS-CoV-2 virus depends on its spike protein to bind ACE2, the host cellular receptor. To more...point for SARS-CoV-2 researchers to investigate how the virus interacts with human cells. Addgene’s mammalian...genes are important for SARS-CoV-2 entry into human lung epithelial cells (Biering et al., 2021). In their...Wesemann DR (2021) Memory B cell repertoire for recognition of evolving SARS-CoV-2 spike bioRxiv. https://...labs in over 75 countries. Figure 1: SARS-CoV-2 proteins and other components. Image from Maya Kostman...
  25. Reagent Repositories Are Speeding up Science During the Pandemic

    Type
    Blog Post
    Published
    Aug. 4, 2020, 1:15 p.m.
    ...Everyone. Case study 1: Cell lines Many of the reagents used to investigate SARS-CoV-2 were developed for ...different organisms to SARS-CoV-2 (Chu et al., 2020). An additional cell line used in this study came from...tropism, replication kinetics, and cell damage profiling of SARS-CoV-2 and SARS-CoV with implications for...fast access to the tools required to study SARS-CoV-2, but with many academic research labs closed during...biobanks, are crucial for the advancement of SARS-CoV-2 research because they provide rapid access to validated...that science is truly a global endeavor. Case study 2: Plasmids Another example of reagents that have broad...applications but have proven useful to the study of SARS-CoV-2 are the lentiviral production and packaging vectors...
  26. AAVs CREATed for Gene Delivery to the CNS and PNS

    Type
    Blog Post
    Published
    Sept. 28, 2017, 2:01 p.m.
    ....9 (parental) 46 +/- 0.7% AAV.PHP.S 82 +/- 2% Table 2: Transduction efficiency of AAV.9 versus AAV.PHP.S...figure 2) to allow for efficient IV delivery of virus to the CNS or PNS (figure32, tables 1 & 2). These...that cells are labeled with their own unique color; and 2) low levels of labeling so that a cell’s projections...in tables 1 and 2, with a cell-type specific promoter or enhancer now allows for cell-type-restricted ... overall (GFP+ cells that also stained for a neuronal marker). Check out tables 1 and 2 below for a summary...high dose to maximize the number of cells that are labeled. Part 2: An AAV expressing the inducer (i.e...require the generation of a transgenic mouse. 2. Cell-type-specific restricted transgene expression in...
  27. New and Upcoming Viral Vectors - May 2020

    Type
    Blog Post
    Published
    May 28, 2020, 1:15 p.m.
    ...pLVX-EF1alpha-SARS-CoV-2-N-2xStrep-IRES-Puro: Expression of the SARS-CoV-2 N protein  pLVX-EF1alpha-SARS-CoV-2-M-2xStrep-IRES-Puro...SARS-CoV-2 M protein pLVX-EF1alpha-SARS-CoV-2-orf3a-2xStrep-IRES-Puro: Expression of the SARS-CoV-2 ORF3a... SARS-CoV-2 protein expression The Krogan lab quickly shared plasmids expressing SARS-CoV-2 proteins at...pLVX-EF1alpha-SARS-CoV-2-E-2xStrep-IRES-Puro) and NSP2 (pLVX-EF1alpha-SARS-CoV-2-nsp2-2xStrep-IRES-Puro...months: Lentiviral preps for expressing SARS-CoV-2 proteins ChR2 for targeted expression DREADDs GFP ...Serotype Name 83899 AAVrg pAAV-mDlx-GCaMP6f-Fishell-2  Additional resources on the Addgene blog Read... results, but also confirm expression in target cells. While the various AAV serotypes can be used to ...
  28. Which Fluorescence Microscopy Techniques is Best for Me?

    Type
    Blog Post
    Published
    Oct. 10, 2017, 1:57 p.m.
    ...the image can be acquired more quickly. 2-Photon Microscopy 2-Photon Microscopy attempts to solve two ...Fluorescence microscopy. Nature methods 2, 910-919 (2005). PubMed PMID: 16299476. 2. Conchello JA, Lichtman JW. Optical...provide a 2-10 fold increase in resolution, down to 10s of nanometers. Thick dynamic samples Ex: 3D cell cultures...enhance spatial contrast (i.e. optical sectioning (2) or super-resolution (3). Fluorescence microscopy...photobleaching and a reduction in signal intensity. 2-Photon microscopes restrict excitation (and bleaching...can be seen exiting through the tissue. Therefore, 2-photon allows for deeper imaging into thick tissues...imaging objective that collects fluorescence. Like 2-photon microscopy, only a single focal plane of the...
  29. Hot Plasmids Spring 2024

    Type
    Blog Post
    Published
    May 23, 2024, 1:15 p.m.
    ...Anti-SARS-CoV-2 Nucleocapsid Protein [mBG86], target distinct epitopes on the SARS-CoV-2 nucelocapsid protein...repository of tools for SAR-CoV-2 research. Two new antibodies, Anti-SARS-CoV-2 Nucleocapsid Protein [mBG17...Anti-SARS-CoV-2 Antibodies here! Terry, J.S., et al. (2021). Development of a SARS-CoV-2 nucleocapsid ...domain, PE7 (Figure 2).  PE7 shows enhanced editing efficiencies in a number of cell types at different...Figure 3).      Figure 3: HeLa cells transduced with SARS-CoV-2 nucleocapsid protein (Plasmid #141391...prime editor PE7 Antibodies to facilitate SARS-CoV-2 research New viral vector preps of Voltron2 voltage...editor. Find PE7 plasmids here!     Figure 2: PE7 improves prime editing. A) Schematic of PE7 prime...
  30. Hot Plasmids and Viral Preps - May 2021

    Type
    Blog Post
    Published
    May 18, 2021, 1:15 p.m.
    ...SARS-CoV-2 infects host cells through binding the human angiotensin converting enzyme 2 (ACE2) cell-surface...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus may acquire mutations to escape ...Figure 1. (A) SARS-CoV-2 RBD DMS Library generation and sequencing. From Starr et al Cell., 2020. (B) Mapping...designed so that the SARS-CoV-2 spike RBD is displayed on the yeast cell’s surface. The Bloom lab used ...Pooled library to study antibody escape in SARS-CoV-2 Recombinant antibodies for aminoacyl tRNA synthetases...viral preps Mapping antibody escape in SARS-CoV-2 by mutational scanning By Seth Kasowitz As multiple... binding ACE2 is the target of most anti-SARS-CoV-2 antibodies. In the library, each plasmid encodes the...
  31. Gendered Innovations: Why Does Sex of the Cell Matter?

    Type
    Blog Post
    Published
    July 21, 2016, 2:30 p.m.
    ...state-of-the-art methods of sex and gender analysis and 2) provides case studies with concrete examples of how...never considered the sex of their cells. For one thing, cells and cell lines degenerate over time—and sex... effects of using all female cells and tissues, specifically in stem cell therapies. Let’s go back to ...therapeutic capacity of stem cells. Yet, very few researchers consider the sex of their cells when doing experiments—which...sexes in basic research is excellent design), but they used all female stem cells—this was an unconscious... stem cells. Nor did they detect important differences in function between male and female cells. The ...experiment. In the case of stem cells, these factors may include cell type, the disease being treated,...
  32. Hot Plasmids - June 2020 - Barcoded CRISPR Library, Sparse Cell Labeling, Calcineurin Reporter, and DNA Staining Dye Alternative

    Type
    Blog Post
    Published
    June 2, 2020, 1:15 p.m.
    ...interest in the cells you are studying. Read our SPARC blog post for more details. Figure 2: Dense (c... rising intracellular calcium levels within the cell. When levels of Ca2+ are high in the cell, calcineurin...infection (MOI) during cell library construction to ensure that the majority of cells receive one gRNA. The... of a genetically-defined subset of cells. By labeling fewer cells in a population, it’s easier to visualize...lengths, the density of cells that are labeled can be altered to dense (45% of cells labeled), intermediate...or aging cell populations. Figure 3: Micrographs of wild type (top panels) and cells with high...barcodes (iBARs) in their loop region. After infecting cells with sgRNAiBAR library containing lentiviral vectors...
  33. Antibody Neutralization Response Against Pseudoviruses Expressing SARS-CoV-2 Spike Protein Variants

    Type
    Blog Post
    Published
    June 22, 2021, 1:15 p.m.
    ...Multiple SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity. Cell 184:2372-2383...months, we’ve seen the emergence of several SARS-CoV-2 variants coincide with increased vaccination efforts...They were able to tweak this assay to study SARS-CoV-2 spike variants. “We created a series of spike expressing...relative ability to neutralize.”   Figure 2: Sera used in the study came from individuals who ...This sera was used in the high-throughput SARS-CoV-2 pseudovirus neutralization assay. Neutralization was...viruses are quite genetically distinct from SARS-CoV-2 and its variants. Yet, the B.1.351 variant, which ...effectiveness of current vaccines against SARS-CoV-2 variants, this study was the first to compare so many...
  34. Synthesized by Ginkgo Bioworks, Shared by Addgene: SARS-CoV-2 Plasmids for Many Expression Systems

    Type
    Blog Post
    Published
    May 19, 2020, 1:15 p.m.
    ...Illustration of SARS-CoV-2 from Philippa Steinberg for the IGI.   What SARS-CoV-2 plasmids from Ginkgo ...share over 1,850 SARS-CoV-2 plasmids to help academic and industrial labs accelerate research and to help ...request? Currently, plasmids containing all SARS-CoV-2 protein coding genes in E. coli and S. cerevisiae ...bacterial expression systems, Ginkgo synthesized SARS-CoV-2 expression plasmids in a high copy backbone with a...high level expression and purification of SARS-CoV-2 proteins for downstream experiments and offer flexibility...optimized, full length and truncated versions of SARS-CoV-2 S (spike protein) cloned into a CMV driven expression...first deposited set of plasmids containing SARS-CoV-2 protein coding genes in E. coli and S. cerevisiae ...
  35. Scientists Map the SARS-CoV-2-Human Interaction Network

    Type
    Blog Post
    Published
    April 9, 2020, 1:15 p.m.
    ...comprehensive SARS-CoV-2 virus-human interaction network in which we expressed 26 of the 29 SARS-CoV-2 viral proteins...understanding how SARS-CoV-2 interacts with human proteins. For example, we used HEK293T cells in our first study...all became acutely aware of the threat of SARS-CoV-2. Like many in the science community, we’ve been motivated...identifying these potential human helpers of SARS-CoV-2 (especially the ones that are druggable) is a key ... joining in this worldwide fight against SARS-CoV-2. As we’ve all been affected in various ways by the...details. Our set of constructs comprises all SARS-CoV-2 viral proteins except for Nsp3 and Nsp16, and includes...is going on there!).  Find the Krogan Lab SARS-CoV-2 plasmids (Note: The Nsp6 construct is undergoing QC...
  36. Plasmids for Endogenous Gene Tagging in Human Cells

    Type
    Blog Post
    Published
    April 6, 2017, 1:02 p.m.
    ...this year. Designing the donor plasmid Figure 2: Donor plasmid design strategy. A donor plasmid contains...Institute for Cell Science. Learn more by visiting the Allen Cell Explorer at allencell.org and the Allen... hiPS cell lines generated using these plasmids, please visit the Cell Catalog on the Allen Cell Explorer... tagging to elucidate cellular structures. Overexpression methods flood the cell with protein, which can... in human cell lines. Furthermore, the quality control necessary to ensure the edited cells are behaving..., and the stem cell lines we’ve made using them are available as part of the Allen Cell Collection at ...
  37. Adenoviral Vector Production and Troubleshooting

    Type
    Blog Post
    Published
    June 14, 2018, 11:44 a.m.
    ...change the media (add 2-3 mL of fresh media once a week), and do NOT harvest the cells before at least 10...titer. Amplification (1-2 weeks) - The rAdV-S is used to infect more HEK293 cells and produce more rAdV ...infected cells show this “cytopathic effect.” Amplification can be repeated multiple times (2-4 rounds...creating adenoviral vector constructs. It consists of 2 plasmids: a shuttle vector (in which the transgene...Addgene’s Adenoviral Guide webpage, and references 1, 2.*Pro-Tip*: once the correct recombinant pAdV plasmid...sequenced to confirm its integrity. Initial production (2-3 weeks) - Here you’ll produce the primary recombinant...rounds) at increasing scale over the course of 1-2 weeks. Each round of amplification should result in a 10...
  38. Viral Vectors 101: Pseudotyping

    Type
    Blog Post
    Published
    April 20, 2021, 2:30 p.m.
    ...safely. Recently, many SARS-CoV-2 researchers began pseudotyping the SARS-CoV-2 spike protein into a lower ... et a., 2018).   Figure 2: To pseudotype with the SARS-CoV-2 spike protein, scientists encode...of vesicular stomatitis virus, HIV-2, and human foamy virus in cell lines expressing galactosyl(alpha1...spike protein’s role in infecting cell lines without using intact SARS-CoV-2 virus. Scientists have been using...Particles Produced in Human Cells Are Inactivated by Human Serum. Molecular Therapy 2:218–222 . https://doi....production uses three plasmids: (1) The transfer plasmid, (2) the envelope plasmid, and (3) the packaging plasmid... pseudotyping methods with other viruses in a BSL-2 lab instead of a BSL-3 or BSL-4 lab. For more details...
  39. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

    Type
    Blog Post
    Published
    May 5, 2020, 1:15 p.m.
    ... State University. Since its appearance, SARS-CoV-2 has spread to almost every part of the world manifesting...Rapid detection of 2019 novel coronavirus SARS-CoV-2 using a CRISPR based DETECTR assay Sensitivity:10-...primers that target the E and the N2 gene of SARS-CoV-2. If the Cas12a-sgRNA complex binds to the target sequences... method has been optimized to detect the SARS-CoV-2 virus directly using saliva without having to perform...and visual detection of novel coronavirus SARS-CoV-2 Sensitivity: 4.6-11 copies/microliter of RNA targets...single-molecule sensitive. In the case of HIV-1 and SARS-CoV-2 detection, AIOD-CRISPR without preamplification was...easy-to-deploy, protocol for Cas13-based detection of SARS-CoV-2 genetic material (CREST) Sensitivity: 10 copies of...
  40. Viral Vectors 101: Virus Safety

    Type
    Blog Post
    Published
    June 22, 2023, 1:15 p.m.
    ...cancer. These viruses need to be handled in a BSL-2 (or BSL-2+) lab and require additional safety measures.... BSL-1. In BSL-2 labs, eye protection is required any time you have to work with BSL-2 materials, such...respiratory diseases in humans, earning this virus a BSL-2 classification. Lentivirus (a type of retrovirus) ...recommended or required in BSL-1 and required in BSL-2 labs. When working with lentivirus, many organizations...sprayed into the air. For lentivirus and other BSL-2 materials, you’ll need to use aerosol-tight caps, ...percentage of the decontaminate to be used for BSL-2 waste, and of course, if you are working with a substance...producer cell line, such as HEK-293T, production of viral particles, and transduction of a target cell line...
  41. 10 Basic tips for mammalian cell culture

    Type
    Blog Post
    Published
    July 12, 2018, 1:09 p.m.
    ...: 24901218. PubMed Central PMCID: PMC4047077. 2. Pagliara, Patrizia, et al. "Ostreopsis cf. ovata induces...times), depending on the cell line so old cells should be retired! Conversely, cells younger than the 3rd ...Make sure cells don't stay out too long While you’re preparing things, make sure your cells don’t stay...contaminants. Set up a routine to split cells Don’t be lazy about splitting cells, instead try to form a routine...’s best to split cells before the plates are more than 80-85% confluent because cells like their space...lactic acid (a by-product of cellular metabolism that is toxic to the cells), and need to be split very...numbers! When starting off with a new cell line, grow the cells, aliquot them into a number of vials, ...
  42. The Challenges of Cell Culture

    Type
    Blog Post
    Published
    May 5, 2016, 2:30 p.m.
    ... 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...
  43. Typing CRISPR Systems

    Type
    Blog Post
    Published
    March 18, 2025, 1:15 p.m.
    ...   Class 1 versus class 2 There are two CRISPR classes: Class 1 and Class 2. Class 1 CRISPR systems use...systems to carry out various functions. Class 2 Class 2 CRISPR systems rely on a single protein Cas effector...explore Class 2 CRISPR in more depth, the Jennifer Doudna lab maintains an encyclopedia of Class 2 CRISPR systems...systems: a burst of class 2 and derived variants. Nature Reviews Microbiology, 18(2), 67–83. https://doi.org...). 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...
  44. Plasmids 101: Knockout/Knock-In Plasmids

    Type
    Blog Post
    Published
    Dec. 1, 2016, 3:30 p.m.
    ...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...
  45. Addgene's Top Blog Posts from 2020

    Type
    Blog Post
    Published
    Dec. 29, 2020, 2:15 p.m.
    ...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...
  46. Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering

    Type
    Blog Post
    Published
    Dec. 15, 2016, 3:57 p.m.
    ...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....
  47. Tips for a 1st Time CRISPR User (by a 1st Time CRISPR User)

    Type
    Blog Post
    Published
    March 7, 2017, 3:30 p.m.
    ...   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...
  48. Antibodies 101: Fab Fragments

    Type
    Blog Post
    Published
    Sept. 5, 2024, 1:15 p.m.
    ...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...
  49. Viral Vectors 101: Producing Your rAAV

    Type
    Blog Post
    Published
    July 16, 2024, 1:15 p.m.
    ...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...
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