...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...

...: 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, ...

... 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...

...   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...

...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...

...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...

...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....

...   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...

...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...

...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...

...the resulting fraction is reported. Figure 2: Normalization with loading controls. Under each lane...control band is weaker in condition 1 than condition 2, the normalized values for the two conditions are ...opposite change in your loading control. Assumption #2: The loading control can be accurately quantified ...significantly lighter in “condition 1” than “condition 2.” By eye, the loading control appears about the same...) are smaller than the analogous green “condition 2” points by the exact same value. For the two solid...consider a different loading control. Assumption #2: The loading control can be accurately quantified ...factors we’ve covered in our previous blog posts (1, 2) on western blotting. If the abundance of your POI...

...electrocompetent cells is minimal (picogram range). It can be extracted from small bacterial cultures (i.e. 2-3 ml...ratios measured at 260 and 280 nm should fall ~1.8 - 2 and give scientists an indication of purity versus...contaminants. The 260 and 230 nm ratios should fall ~2 - 2.2, and provide an indication of purity versus ...hydrochloride used during plasmid extraction. Figure 2: Use cloning grade DNA for direct cloning of your ...lipopolysaccharide of the cell wall of Gram negative bacteria like E. coli that affects tissue culture cell line viability...introduces transformation grade plasmids into a bacterial cell. Transformation grade DNA  Transformation is ...Figure 3: Need to introduce plasmids into mammalian cells? Use transfection grade DNA. Transfection is ...

...GEVIs (called ASAP 1 and 2), they found an indicator that is optimized for 2-photon imaging of voltages...challenges in 2-photon in-vivo imaging of voltage fluctuations. Image credit: Liu Z, et al. Cell. 2022.  ...suitable for in vivo optogenetic use.   Fig. 2: A) HcKCR1 is highly selective for K+ over other Na...slice of HcKCR1-EYFP and tdTomato expressed layer 2/3 neurons in mouse. C) Action potential frequencies...two-photon microscopy. Cell, 18, 3408 - 3425.e29. (2022). https://doi.org/10.1016/j.cell.2022.07.013.   ...specific for human c-myc proto-oncogene product. Mol Cell Biol. Dec;5(12):3610-6.(1985). doi: 10.1128/mcb.5.12.3610...

...Table 2 for more details on the effect of pH on the fluorescent properties of Rosella.   Table 2: Effect...in yeast. Autophagy,4(2), 205-213. doi:10.4161/auto.5331. PubMed PMID: 18094608 2. Sargsyan, A., Cai, J...environment like the vacuole or lysosome. See Table 2 for a summary of what color fluorescence Rosella emits...fluorescence accumulates in the vacuole. See Figure 2 for an example of what fluorescence looks like for... Mammalian Autophagy Research. Cell,140(3), 313-326. doi:10.1016/j.cell.2010.01.028. PubMed PMID: 20144757...analyzing autophagy of cytosol and organelles in yeast cells. Autophagy (Greek for “self-eating”) is induced ...radio-labeled long-lived proteins as a proxy for autophagy. Cells are cultured with isotope-labeled amino acids for...

...Journal of Cell Biology. PubMed PMID: 29263082 Find plasmids from this publication at Addgene. 2. Bates,...antibody has an antigen binding site for a total of 2 binding sites per antibody. C) IgG’s are big enough...enough that multiple labels (green circles in figure 2 below) can be attached to each antibody. But being...displacement Require separate incubation of 1° and 2° Must use different species and/or different IgG ...Greater resolution due to lower label displacement 2° incubation can be skipped by pre-binding to 1° ...a fluorescent tag and the target antigen to about 2 nm, which can lead to higher resolution for super-...subclass.   Express the Nanobody In Bacteria: Table 2 also has a link to the plasmid you’ll need to express...

...different steps and materials required for each [1, 2]. This protocol [3] provides, in exquisite detail,...stimulation         In the video above, Channelrhodopsin 2 (Chr2) has been expressed in the motor cortex of a...lasers are relatively cheap and will run you about $2-3,000/laser. However, an important caveat is that ... the light-gated cation channel, Channelrhodopsin 2 (ChR2), exists in several states: closed/light receptive...PMID: 21628464; PubMed Central PMCID: PMC3138296. 2. Sparta DR, et al. Construction of implantable optical...board, Jacqueline N Crawley  [et al]. 2012;Chapter 2:Unit2 16. doi: 10.1002/0471142301.ns0216s58. PubMed...Pharmacology and Optogenetics. Cell 162.3 (2015): 662-674. doi: 10.1016/j.cell.2015.06.058. Pubmed PMID: 26189679...

...eGFP tag, and 2) gRNAs Number of loci targeted One Many Sample type(s) Cell lines Cell lines, primary...Expression system Stable cell line expressing 1) FLAG-biotin-tagged dCas9, 2) BirA, and 3) one or more...Originally published Dec 7, 2017 and updated Jul 2, 2020. Promoters may be the star of gene regulation...sequence targeted in the experiment. Figure 2: Comparing CAPTURE and CAPTURE 2.0.     Original...identified and the level of on-target enrichment. 2. Determining the spatial and hierarchical organization...Cytogenetics, 11. https://doi.org/10.1186/s13039-018-0368-2  Liu X, Zhang Y, Chen Y, Li M, Zhou F, Li K, Cao H... of cells (~5x107). Together, these two requirements prevent the use of CAPTURE with primary cells or ...

...for the 2+ million DHS sites. See below for further details. DNA is a 3D Fractal Figure 2: DNA compaction... we identified in step 2. The result is a heterogenous population of stem cells, usually housed in a single...: 1. Find Enhancers that have NANOG binding sites 2. Design a CRISPR screen to target and disrupt the ...NANOG enhancers 3. CRISPR out the enhancers from step 2. See which ESCs die or differentiate Step 3 reveals...expression for NANOG enhancers, we’re ready for step 2: design a CRISPR screen to disrupt these enhancers... for stem cells, or metastasized tumor cells, or alzheimers-affected neurons, or [your cell line of interest...critical to stem cell survival. Knowing which genes influence the survival of our cell culture is the foundation...

...that have been developed into retroviral vectors and 2.) a subclass of retroviruses called the lentiviruses...effectively. Retroviral structure   Figure 2: Structure of a retrovirus. Image re-used from Dong...Dong & Kantor, 2021 under CC-BY license. Figure 2 gives a detailed view of the structure of a retroviral...transfer of RT, which would actually occur in step 2 during uncoating. After uncoating, reverse transcription...one of the two strands’ DNA counterparts from step 2 will be integrated by the viral integrase protein ... Air. Environmental Science & Technology Letters, 2(4), 84. https://doi.org/10.1021/ACS.ESTLETT.5B00050...synthesized inside of what is called the “target cell” (or host cell) by the viral protein reverse transcriptase...

...reviewed in 2, 5). The minigenome is capable of being replicated and transcribed in the cell when the appropriate...study aspects of the EBOV replication cycle under BSL-2 conditions (4). What is a minigenome?   The EBOV ...nonsegmented negative sense RNA viruses (reviewed in 2, 3). Other important components of the Zaire ebola...as it would for a full-length viral genome (Figure 2). While it is technically possible to encode all four...500 ng NP, 500 ng VP35, 100 ng VP30, 100 ng L, and 2 μg minigenome plasmid per well (in a 6 well plate ...PubMed PMID: 9847328. PubMed Central PMCID: PMC103829. 2. Conzelmann, K. K. "Reverse genetics of mononegavirales...choose cell lines that are highly transfectable.  The amounts of each plasmid transfected into cells are ...