....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...because: 1) their genomes are easy to manipulate, 2) they have long-term expression; and 3) they have ... On average, AAV.PHP.eB and AAV.PHP.S had 1.5- to 2-fold higher GFP intensity compared to the strains ...stained for a neuronal marker). Check out tables 1 and 2 below for a summary of the quantified transduction...cells are labeled with their own unique color; and 2) low levels of labeling so that a cell’s projections...maximize the number of cells that are labeled. Part 2: An AAV expressing the inducer (i.e. tet-off transactivator...

...repeated multiple times (2-4 rounds) at increasing scale over the course of 1-2 weeks. Each round of amplification...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...media will turn yellow. Do NOT change the media (add 2-3 mL of fresh media once a week), and do NOT harvest...it will result in very low titer. Amplification (1-2 weeks) - The rAdV-S is used to infect more HEK293 ...in a 10-100-fold increase in virus. Purification (2 days) - Purification is required if rAdV is to be ...

...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... viruses are more dangerous than others, and the same holds true for types of viruses generated in the...

... that results in a polymerase error rate of up to 2% per nucleotide position. The “sloppy” PCR reaction...modifications: 1) increased concentration of Taq polymerase, 2) increased PCR extension time, 3) increased concentration...to synthesize a complementary mutant strand (step 2 and 3). Then the uracil-labeled template strand is...restrict site matter? Most of the time no, but there are 2 instances where it does. 1) When the backbone vector...ExoIII. See the below figure for an example like this. 2) When your gene of interest has a BbvCI site(s). If...saturation mutagenesis method are 1) ease of use, 2) time savings, and 3) ability to perform single site...PMID: 23766324. PubMed Central PMCID: PMC4409680. 2. Mccullum, E. O., Williams, B. A., Zhang, J., & Chaput...

...and wild type target in each sample can be quickly calculated (details in [2]) and can be used to quantify...resulting from non-homologous end joining (NHEJ) (2-5), depending on your desired genome edit. Since exploitation... have been reported for mismatch nuclease assays (2, 6, 7). Ability to distinguish between mono-allelic...assays, in addition to testing their performance (2). Remember that although digital PCR is a great screening...PMID: 24509632. PubMed Central PMCID: PMC4063274. 2. Findlay, S. D., Vincent, K. M., Berman, J. R. & Postovit... PCR Digital PCR (dPCR) involves splitting up a sample into thousands of physically isolated partitions...of target DNA molecules present in the original sample with a great deal of precision. This means digital...

...to detect SARS-CoV-2 RNA. The test is started using RNA purified from patient samples and can be read using... can be used to diagnose the presence of SARS-CoV-2 RNA, but inadequate access to reagents and equipment...named this system SHERLOCKv2 for SHERLOCK version 2. Here are some of the improvements: SHERLOCKv2 uses...recently adapted the DETECTR platform to detect SARS-CoV-2 using a lateral flow strip format. They published ...CY (2020) CRISPR–Cas12-based detection of SARS-CoV-2. Nature Biotechnology. https://doi.org/10.1038/s41587... and Functional Characterization of Diverse Class 2 CRISPR-Cas Systems. Molecular Cell 60:385–397 . https...Cpf1 Is a Single RNA-Guided Endonuclease of a Class 2 CRISPR-Cas System. Cell 163:759–771 . https://doi....

... be extracted from small bacterial cultures (i.e. 2-3 ml) with or without commercially available kits ...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 ...Not all plasmid preps are the same. Before purifying a plasmid from a bacterial culture, it is important...nucleic acid and chemical contaminants, these DNA samples must also be entirely endotoxin free. Endotoxin...

...PubMed Central PMCID: PMC3640491. 2. Grimm, D., et al. "Titration of AAV-2 particles via a novel capsid ELISA...report the physical titer of a viral solution (Figure 2). Because physical titers are used for dosing purposes...mean and how they can be compared.   Figure 2: Label that comes on Addgene’s AAV aliquots. Our titer...of genomes can limit production of recombinant AAV-2." Gene therapy 6.7 (1999). PubMed PMID: 10455443. ...Characterization of a recombinant adeno-associated virus type 2 Reference Standard Material." Human gene therapy 21.10...each individual sample, this will reduce convenience and comparability because each sample with be quantified... low-concentration samples can also behave differently in PCR, even if both samples fall within the linear...

...digital PCR. Human Gene Therapy Methods, 25(2), Article 2. https://doi.org/10.1089/hgtb.2013.131 Lock,...Pawlita, M., Ferrari, F., Samulski, R., & Kleinschmidt, J. (1999). Titration of AAV-2 particles via a novel... virus Once you have transfected your cells, wait 2–5 days and then collect the supernatant and/or producer...quantification of adeno-associated virus serotype 2-derived inverted terminal repeat sequences. Human ...of 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...known titer on every qPCR run. Note that the rAAV sample has to be digested with DNase before undergoing...

...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... Find plasmids from this publication at Addgene. 2. Bates, M., Böhning, M.I., Chug, H., Görlich, D., ...

...safely. Recently, many SARS-CoV-2 researchers began pseudotyping the SARS-CoV-2 spike protein into a lower ...SARS-CoV-2 virus. Scientists have been using similar pseudotyping methods with other viruses in a BSL-2 lab... et a., 2018).   Figure 2: To pseudotype with the SARS-CoV-2 spike protein, scientists encode...production uses three plasmids: (1) The transfer plasmid, (2) the envelope plasmid, and (3) the packaging plasmid...example, production of vesicular stomatitis virus, HIV-2, and human foamy virus in cell lines expressing galactosyl...for Pseudotyping Lentiviral Particles with SARS-CoV-2 Spike Protein for Neutralization Assays. Viruses 12...Are Inactivated by Human Serum. Molecular Therapy 2:218–222 . https://doi.org/10.1006/mthe.2000.0116 Gutierrez-Guerrero...

...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...instructions in the same producer cells as the virus. Because it is made at the same time as the other ...

...identification.   Fig. 2: Gel image of Plasmid 61564: pBAMD1-2 (~4.7 kb) digested with SpeI and... at ~3.6 kb and ~1.1 kb (lane 3). Uncut DNA (lane 2) has a band at <3 kb, which corresponds to the supercoiled...formation of plasmid multimers. Cell. 1976 Dec;9(4 PT 2):707-16. doi: 10.1016/0092-8674(76)90134-3. PMID: ...dimers in Escherichia coli K-12. Plasmid. 1989 Mar;21(2):138-41. doi: 10.1016/0147-619x(89)90057-7. PMID: ...Plasmids and Chromosomes. Microbiol Spectr. 2014 Oct;2(5). doi: 10.1128/microbiolspec.PLAS-0025-2014. PMID...Behavior of Plasmid DNA. Microbiol Spectr. 2015 Apr;3(2):10.1128/microbiolspec.PLAS-0036-2014. doi: 10.1128...plasmid monomer from a plasmid sample, or if no monomers exist in your sample, you could try linearizing ...

...low expression, and everything in between (Figure 2). These smears tend to occur when you are looking ...based on your experiment. You can see from Figure 2 that determining where to place your gate based on...the dot plot would be complicated.  Figure 2: (A) a smeary dot plot showing a range of antibody...plot in Figure 4 compared to the dot plot in Figure 2. Quantification using MFI makes it easier to identify...105 signal intensity. If your samples and controls were processed the same way, the GFP- population should... control (left) or with the sample (right). Negative and positive samples are clearly distinguishable ...designed your first flow panel, you’ll load your samples into the cytometer and see one of two results for...

...University of Manitoba due to their Biosafety Level-2 or 2+. Please Note: Despite the fact that AAVs themselves...long and stable expression (up to 9 months in mice [2]). Low Immune Response: Compared to other viral vectors... location. Location (1): What tissue? Location (2): Where in the tissue/which cell type? Location (3...may be sufficient to overcome the transport issues. 2. Failure to plan (for storage) Is planning to fail...Find Ready-to-Use Retrograde AAV Preps at Addgene 2) Comparison of genetically engineered receptors (i.e...Therapy 15.10 (2007): 1740-1743. PubMed PMID: 17882145. 2. Zincarelli, Carmela, et al. "Analysis of AAV serotypes... tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain." PloS one 8.9 (...

...fluorescent state make them useful for 2-color imaging with green PA-FPs. Table 2: Properties of Selected Reversible... conventional FP imaging. PA-FPs are divided into 2 main categories - those with irreversible and reversible... forms of the chromophore which contribute to the 2 peaks of wtGFP’s excitation spectrum- a major 397 ... / N99K / S148L / I165V / Q167P / L169V / I203R) (2) and PA-mRFP1(S146H / I161V / I197H) (3) were derived...with two distinct wavelengths of light (see Table 2). The best known reversible PA-FP is the naturally... above background. The majority of PA-FPs come in 2 flavours- monomeric and tetrameric. Tetrameric PA-...most PA-FPs, but, in 2015, the Looger Lab designed 2 variants of EosFP that can withstand these conditions...

...illustrated in the schematic below.   Figure 2: gRNA target sequences (colored rectangles) are cloned... plasmids: This plasmid set allows you to express 2-4 gRNAs, with four being the ideal number. First you...the total number of gRNAs you wish to clone, from 2-7. For example, if you’re expressing 4 gRNAs, you’...gRNAs into spectinomycin-resistant plasmids pX330S-2 to pX330S-(last gRNA number). The 5’ most gRNA is ...Multiplexing Plasmids: These plasmids allow you to assemble 2-4 gRNAs through Golden Gate or Gibson Assembly. gRNAs...Multiplex Plasmids: These plasmids allow expression of 2-5 gRNAs in zebrafish. Custom destination vectors are...and a subsequent curing protocol that requires only 2-3 hours incubation. Kondo Lab multiplexed base editing...

.... To understand why that is, let's look at Figure 2. The blue laser excites at a wavelength of 488 nm ... of PE's excitation spectrum (dotted line, Figure 2). The yellow/green laser, however, excites at 561 ... stronger — or brighter — signal.   Figure 2: Excitation and emission spectra for PE. The excitation...this example, I will describe a basic panel (Table 2, Figure 5) for a hypothetical experiment in the lab...efficiency (eGFP expression).     The first item in Table 2 is a standard and should always be included—the live...from the other fluorophores to avoid bleeding and 2) BV421 is a very bright fluorophore, which makes it...case the CD45 expression turns out to be weak. Table 2: A simple flow panel to detect live, transduced, and...

...improving editing accuracy by preventing re-editing and (2) optimizing “cut-to-mutation distance”. Furthermore...also takes into account that HDR is rare, usually 2-5% of the edited cells in our hands, these combined...screen a few hundred clones to find the right one Step 2 – Edit the cells a second time using a repair template...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... events were corrupted by unwanted indels on the same allele, probably due to concomitant NHEJ repair....

...for the 2+ million DHS sites. See below for further details. DNA is a 3D Fractal Figure 2: DNA compaction...: 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...to CRISPR out the enhancers we identified in step 2. The result is a heterogenous population of stem cells...lentiviral vector, an attenuated retrovirus in the same family as HIV. By design, our lentivirii are genetically...very-sensitive-local -L 9 -N 1 -U GRNA_23MERS -S GRNA_HITS.sam Many thanks to our guest blogger, Aneesh Karve...