...fragments that retain antigen binding (Figure 2):  F(ab')2 - These fragments are produced by proteolytic...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...multiplexed super-resolution microscopy. Cell Rep Methods 2(10):100301. https://doi.org/10.1016/j.crmeth.2022.100301...

... step of the series dilutes by 1:2 for a series that ranges from 1:2–1:32. The specific dilution series...series ranging from 1:2 to 1:32. Each individual step of the series is consistent at 1:2. When preparing a...of the series diluted by the same factor. For example, Figure 1 depicts a 2-fold dilution series. Each ...the unknown sample based on its measured response. An example of this is shown in Figure 2.   ...accuracy of the curve, avoid pipetting small volumes (< 2 µL) or volumes too large for a standard micropipette... Figure 2: The concentration of a serially diluted standard is plotted against its OD560 measurements...molecule in an unknown sample. To do this, you serially dilute a control sample of known concentration...

...recruits transcriptional activators such as VP64, SAM, or SunTag to specific ncRNA loci to enhance or upregulate...You’ve probably heard that only 2% of our genome is made of protein-coding genes, and you might be wondering...insertions or deletions in the DNA sequence. This same approach is effective to target short ncRNAs, such...useful for targeting thousands of long ncRNAs at the same time (Liu et al. 2018). However, removing large ...

...arePharmacologically Selective Actuator Modules (PSAMs, pronounced SAMs). PSAMs are engineered α7 nicotinic acetylcholine...Figure 3: PSAM4-based ligand-gated ion channels, their effect, and outcome in neurons. Table 2. Descriptions...muscarinic receptor and has not been used in vivo . Figure 2: DREADDs, their ligands, and signaling properties.... Reference Rq(R165L) Human M3 muscarinic Arrestin-2/-3 CNO* Increase Arrestin translocation Arrestin signalling...hM1Dq hM5Dq Human M3 muscarinic G αq CNO* Increase Ca 2+ Neuronal burst firing Armbruster et al., 2007 rM3D...Forbes SL, Liggett SB (2001). Modification of the beta 2-adrenergic receptor to engineer a receptor-effector...varenicline. This PSAM carries mutations at L131G, Q139L, and Y217F and is termed PSAM4 (or PSAM 4 ). Additional...

...sequence YFP Thorben Dammeyer 54520 mCherry-Peroxisomes-2 Peroxisome Peroximal Targeting Signal 1 (PTS1) mCherry...Centrin2 Centrioles (dependent on cell cycle) Centrin-2 EGFP Erich Nigg 41151 pEGFP Cep170 C-term Centrioles...can assess whether your protein is targeted to the same structures as these well-characterized proteins....

...status of MEK1/2 was tracked at 5 minute intervals via Western blot. Phosphorylation of MEK1/2 peaks at just... phosphorylated MEK1/2 levels, suggesting PP1/PP2A is responsible for this MEK1/2 negative feedback. ...PubMed PMID: 28232577. Figures 2-4 were modified from this reference. 2. Regot, Sergi, Jacob J. Hughey...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...hypodermis and gut cells of C. elegans causes the same phenotype. Activation of the Raf-MEK-ERK signaling...

... the 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... when scientists talk about their precious RNA samples. RNA is inherently less stable than most macromolecules...CRISPR-Cas9 experiments – the “gRNA” – suffers from the same issues as your experimental RNA. To solve this problem...protein and can increase on-target efficiency. In the same vein, locked nucleic acids or bridged nucleic acids...

...   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...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...components present in the Cascade complex. Figure 2: Schematic of a Cascade complex (blue subunits) with...

....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 ...