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  1. Technologies Enabled by NanoLuc® Luciferase

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    ...GpNLuc and OgNLuc are available through Addgene (Cat.# 70185 and 70186, respectively). Antares Chu, J...construct for Antares is available through Addgene (Cat. # 74279). Enhanced Nano-Lanterns  Suzuki, K., et...furimazine by Promega’s Chemistry group is a good story (1). From a deep sea shrimp to a compact powerhouse of...cellular analysis products at Promega.     References 1. Hall, M.P., et al. (2012) Engineered luciferase reporter...et al (2). In this post, I’ll cover two great applications of the NLuc technology. The first couples NLuc...fluorescence. The paper reports a wide variety of applications of the Enhanced Nano-Lanterns including monitoring...2017) Genetically encoded bioluminescent voltage indicator for multi-purpose use in wide range of bioimaging...
  2. Better Dyeing Through Chemistry & Small Molecule Fluorophores

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    ...environments such as live cells and tissues (Figure 1). These flexible strategies give you the best of both...majority of in-cell labeling strategies have two parts: (1) a genetically encoded “tag” expressed as a fusion...Follow him on twitter @rhodamine110.   References 1. Liu, Zhe, Luke D. Lavis, and Eric Betzig. "Imaging...Subsequent advances in fluorescent proteins have replicated many of the properties once exclusive to small-molecules...phosphopantetheinyltransferase) – These enzymes catalyze the covalent attachment of a fluorophore ligand...labels for fixed-cell imaging, not for live-cell applications. Thus, these fluorophores are often bulky and...the Addgene Blog Learn About Other Protein Tags Catch Up on Your Fluorescent Protein Background Which ...
  3. Don’t FRET: Bimolecular Fluorescence Complementation Makes Visualizing Protein-Protein Interactions Easy

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    ...tethered to bring them into close proximity (Figure 1). Formation of the complete FP results in a fluorescent...detected by fluorescence microscopy. Figure 1: How BiFC works. A split FP (e.g., yellow fluorescent... protein interactions in living cells. Nat Protoc 1:1278–1286. https://doi.org/10.1038/nprot.2006.201 ...PIPs, resulting in a fluorescent readout.   Applications for bimolecular fluorescence complementation...resulting from the assayed PPI. This high-throughput application is much more straightforward to carry out because...protein construction, cellular expression, and quantification (Kerppola, 2006, 2013). These are described... supraphysiological expression levels. BiFC quantification This is where BiFC outshines FRET — BiFC experiments...
  4. Tips for Screening with Yeast Two Hybrid Systems

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    ... fusions that retain their individual activities (1). Researchers also discovered the modular format of...systems could be combined effectively (3). In Figure 1 for instance, the DBD of the fusion protein shown ...ubiquitin system has been devised (8). References 1. Casadaban M.J., Martinez-Arias A., Shapira S.K., ... can often be accounted for using appropriate replicates and controls (see Tips below), and by validating...two-hybrid screening Minimizing false positives: Run replicates of the experiment to reduce the likelihood of...expression and correct folding, post-translational modification, protein degradation, access to the nucleus ...co-expression of the enzyme responsible for the modification in the assay host strain can help. In order...
  5. 27 Hot Plasmids from 2016

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    ...a rate of up to 1 per 500-1000 bp. In comparison, the DNA replication error rate is 1 per 109 bp. Unlike...variety of biological applications. First, GMAP-compatible backbones for lentivirus LV 1-5 and retrovirus ...Transcriptional Output-TANGO (PRESTO-TANGO) to screen the NCC-1 library of approved drugs against the entire kit; ...generated 5 common 30bp overlap sequences (Sites #1-5). Each overlap site encodes a unique restriction...is multiplex automated genome engineering (MAGE) (1). MAGE uses recombineering (2) to simultaneously incorporate...of GFP (SEP) by a 9 amino-acid linker (see Figure 1). The key to the biosensor lies in pH: DsRed is relatively...inactivate SEP and leave only DsRed to fluoresce (1). With variants that can be targeted to specific cellular...
  6. CrispyCrunch: High-throughput Design and Analysis of CRISPR+HDR Experiments

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    ...This gives each guide a score ranging between 0 and 1. The cutting frequency determination (CFD score) is...converted to a weight (which ranges between 0 and 1) so that they can be used in the rank equation above...converted to a weight (which ranges between 0 and 1) (shown in the graph below) so that it can be used...HDR. Optimal mutation in-depth One the most sophisticated features of CrispyCrunch is how it mutates guide...
  7. Light Sheet Fluorescence Microscopy

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    ...microscopic resolution for studying colloidal gold (1).  The method was based on using a thin plane (sheet...Siedentopf, and R,. Zsigmondy.  (1902) Ann. Phys.  315, 1 – 39.
 A. H. Voie, D. H. Burns, F. A. Spelman. (1993...microscopy/en_de/products/imaging-systems/lightsheet-z-1.html ...of LSFM microscopes (3,4). After this initial application, Stelzer’s group described the single-plane or...brightness with increasing depth caused by light scattering and absorption.  Finally, the photomultipliers...
  8. Hot Plasmids - October 2022

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    ...the predecessor GEVIs (called ASAP 1 and 2), they found an indicator that is optimized for 2-photon imaging...several other constructs in plasmid form. Fig. 1: Summary of the approach and outcomes of the screen...what you'll find in this post: Improved voltage indicator: JEDI-2P Novel class of light-gated potassium...-Myc [9E10] now available! Improved voltage indicator: JEDI-2P  by: Brian O'Neill  The François St-Pierre...have successfully developed an improved voltage indicator (GEVI) called JEDI-2P. Using a custom, high-throughput...screen for improved genetically-encoded voltage indicators (GEVIs) based on the ASAP sensors. The resultant...Sustained deep-tissue voltage recording using a fast indicator evolved for two-photon microscopy. Cell, 18, 3408...
  9. Summer SciComm: Science Storytelling

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    .... In literary terms, conflict can be defined as (1) the struggle between two opposing forces or (2) the...journey even when they know the ending.    Fig. 1: We all know that the superheroes win in the end. ...formal scientific communications, they are fantastic fodder for science communication. The trick is to ... is far from the only way to communication science. Science communicators also use the hero’s journey,...this small glimpse into the world of science communication and can use what you've learned to share your...Finding Conflict in Science  In all science communication, what you are doing is telling a (nonfiction...details often aren’t included in scientific communications, but they’re firmly part of the story to the...
  10. Genetically-encoded Sparse Cell Labeling - A SPARC of Innovation

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    ... Figure 1: SPARC and SPARC2 use the GAL4-UAS system along with precisely truncated attP sites to... several common genetic tools in Drosophila (Fig. 1):  GAL4-UAS, a transcription factor binding site....of PhiC31. In the SPARC system, attP sites are located on either side of a stop cassette, upstream of ...amount of labeling, you can alter the attP site. Truncating the attP site upstream of the stop cassette results...population is directly correlated to the length of the truncated attP site. The three SPARC variants, based on ...intermediate (d), and sparse (e) labeling of the calcium indicator, GCaMP6f, in the Drosophila optic lobe. Image ...Image from Isaacman-Beck et al., 2019. Applications for SPARC SPARC technology is versatile and can be ...
  11. Polymerase Chain Reaction Overview and Applications

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    ...target DNA quickly and accurately.  Figure 1: Steps in PCR reaction   This process of denaturation...extension is repeated 25-35 times to exponentially replicate the target DNA of interest. This entire reaction...have been developed for different scientific applications. These PCR methods all use the same basic PCR...the final cycles which would slow or stop PCR amplification. Other times, the PCR reaction may not be 100%...quantified by qPCR. qPCR is used in a variety of applications including gene expression profiling, studying...concentration, unlike qPCR where results can vary across replicates. ddPCR can be used to quantify DNA sequences ...droplet contains the material required for PCR amplification. Following the PCR reactions each droplet is...
  12. Plasmids 101: Antibiotic Resistance Genes

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    ...into E. coli is a fairly inefficient process– just 1 out of 10,000 cells on average! Without some means...down especially fast and plates should be used witin 1 month for optimal efficiency. Beware of satellite ... perspective – a plasmid-containing cell must replicate the plasmid in addition to its own chromosomal...fully synthetic compounds. Antibiotics can be categorized based on whether they directly kill bacteria ...bacteriostatic); however, the distinction between the two categories may be a bit of a gray area as some bacteriostatic...Blocks 50S ribosomal subunit; inhibits aminoacyl translocation Bacteriostatic 50-100 ug/mL in EtOH Polymyxin...Binds 50S ribosomal subunit; inhibits peptidyl translocation Bacteriostatic 5-25 ug/mL in EtOH *In prokaryotes...
  13. Viral Vectors 101: Parts of the AAV Transfer Plasmid

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    ...and take a look at each of its parts. Figure 1: Parts of an AAV transfer plasmid. Parts shown in ..., ubiquitous expression, while the human synapsin 1 promoter is neuronal specific (Haery et al., 2019)...contains the proteins needed for the virus to replicate,  and the transfer plasmid which contains the ... by the AAV. On a plasmid map, its sequence is located between the ITRs. It can be anything you like as...expression of your transgene to a specific species or location. Promoters can also drive different levels of ...sequences that can flank the transgene and are located between the ITRs. Transfer plasmids often have ... the expression of your transgene. The WPRE is located at the end of the AAV genome, just upstream of ...
  14. Early Career Researcher Toolbox: Free Online Molecular Biology Tools

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    ...more tools for plasmid mapping and design (Figure 1). Benchling: While you might think of Benchling as...Davis from the University of Utah.   Figure 1: A plasmid map created in SnapGene of Blue Flame plasmid...tackling these particular tasks, but they tend to be scattered about the internet. To help you keep your virtual...: Find sequences for plasmids assembled from publications and commercially available sources, as well ... as expression patterns, post-translational modifications and polymorphisms Codon optimization tool: To...making it ready to copy and paste into other applications Primer design tools Many of the above-listed... well as primer design for different cloning applications. Primer3 and Primer3Plus: For general primer...
  15. Year of the Camelid: Antibody Style

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    ... similar antibodies in llamas and alpacas (Figure 1). At the time, researchers were already on a quest...nanobodies (Arbabi-Ghahroudi, 2017)!      Figure 1: Comparison of a heavy-chain only antibody and single-domain...composed of camels, llamas, and alpacas (and their undomesticated counterparts) - not exactly species that jump...to sdAbs becoming valuable tools for diverse applications. For example, RANbodies can be used as an alternative... excitement around using sdAbs in diagnostic applications. For example, fluorescently and radioactively...heavy-chain only antibodies. (A) Overview of genetic modifications made to generate the nanomouse. (VHH = variable...inspired this versatile family of tools, the applications they have already enabled, and the discoveries...
  16. Allen Institute for Brain Science AAV Enhancer Collection

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    ...Tools Atlas (Link opens in a new window) . Figure 1: Selection, prep, and testing of AAV enhancers in ...Brain Science AAV Enhancer Collection Plasmids Publications Resources Enhancer AAV plasmids are plasmids...= Substantial non-specific labeling observed Publications Ben-Simon, Y., Hooper, M., Narayan, S., Daigle...
  17. Comparing Cas9 to NgAgo: Can the Argonautes Best CRISPR?

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    ...removing 1-20 nucleotides from the cleavage site specified by the gDNA. Depending on your application, this...About NgAgo User's First Impressions Here References 1. Gao, Feng, Xiao Z. Shen, Feng Jiang, Yongqiang Wu...template is supplied. Find Plasmids from the NgAgo Publication at Addgene Cas9 and NgAgo head to head NgAgo ...differences in cleavage efficiency. If this finding is replicated in larger studies, it will represent a key advantage...PubMed PMID: 27136078. Find plasmids from this publication at Addgene. 2. Swarts, Daan C., et al.  “DNA-... PMCID: PMC4697943. Find plasmids from this publication at Addgene. 3. Swarts, Daan C., et al. “Argonaute...
  18. Natural or synthetic? How Addgene’s dataset reveals trends in biological innovation

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    ...from distantly related organisms. In 2006, less than 1% of the genes deposited at Addgene were synthetic....synthetic biology is expanding rapidly.  References 1. Kunjapur, Aditya M., Philipp Pfingstag, and Neil ...published their results in a paper in Nature Communications announcing a new bioinformatics tool that can...at its sequence. MIT collaboration for gene classification This inquiry started when Neil Thompson, a ...have generated robust tools that have practical applications in monitoring the accidental or intentional ...from farther away in the tree of life." Nature communications 9.1 (2018): 4425. PubMed PMID: 30356044. PubMed...the lab-of-origin of engineered DNA." Nature communications 9.1 (2018): 3135. PubMed PMID: 30087331. PubMed...
  19. Hot Plasmids and Viral Preps - July 2021

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    ...organoid model (Sun, et al. 2021).  Figure 1: Example schematic from the Organoid EasyTag system...without altering that of the internal control (Fig 1). Because this method relies on the fluorescence ratio...be used to generate organoid cultures with a modification of interest. While the authors optimized the...mechanisms related to morphogenesis, cell fate specification, and human disease.     Sun, et al. bioRxiv...protoplasts, the enzymatic biosensor retains its catalytic activity.  As SLs are also known to trigger seed...parasitization of cereal crops. As a result, agricultural applications of these novel biosensors could have a major...
  20. CRISPR Challenges: Standardization and Homology Directed Repair

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    ...B. Gurumurthy, and Masato Ohtsuka. Nat Protoc. 13(1) (2018):195-215. PubMed PMID: 29266098 Creating knock-in..., with protocols using dsDNA templates achieving ~1-10% efficiency. Easi-CRISPR uses a long ssDNA template...the gRNA design process and rules for various applications is necessary going forward. The standardization... I think I may have finally grasped just how complicated DNA repair pathways are. I fully admit to being...Alt-NHEJ), has been harnessed for CRISPR knock-in applications. CRISPR 101: Targeting RNA with Cas13a (C2c2...for CRISPR Genome Editing Other resources and publications CRISPOR gRNA design tool Researchers at the ...
  21. Illuminating Choices: A Guide to Selecting Fluorescent Dyes and Ligands

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    ...principles of fluorescent dyes/ligands Figure 1: Example structures of fluorophores, fluorescent dyes... dopamine D2/D3 receptors. Scientific Reports, 10(1), 21842. https://doi.org/10.1038/s41598-020-78827-...for bacterial imaging . Microbiology Spectrum, 12(1), e0369023. https://doi.org/10.1128/spectrum.03690...Biochimica et Biophysica Acta - Biomembranes, 1838(1), 15–33. https://doi.org/10.1016/j.bbamem.2013.09.005...emission wavelengths, which are pivotal in their application in biotechnology (Grimm & Lavis, 2022). These... substrates/peptides and antibodies. Example applications of this include coupling to an antibody, whereby...whereby excitation of blue light will indicate where FITC is bound through green light emission. Key considerations...
  22. Plasmids 101: Plasmid Incompatibility

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    ...antisense RNAs inhibit plasmid replication.   Figure 1: The replication problem. Iterons are repeated...actually does, and neither plasmid is maintained (Figure 1).  The partitioning problem Plasmid incompatibility...Agrobacterium tumefaciens. Genes & Genetic Systems 77:1–9 . https://doi.org/10.1266/ggs.77.1 Pubmed PMID: ...Origin of Replication? See our Plasmids 101: Origin of Replication blog).  The replication problem Plasmids...directly inhibit replication by binding to the origin of replication and blocking replication machinery (del... of microbial plasmids: classification and identification based on replication and transfer systems and...plasmid that contains the origin of replication and the replication control machinery (Need a refresher...
  23. Twenty Years of Sharing: Addgene's Viral Vector Service

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    ...By the end of 2023, our catalog had grown to 879 viral catalog items (Figure 1). The service caught on...over 100,000 viral vector preps!   Figure 1: A) Cumulative AAV preps available in the Addgene ...Neuromethods, 195, 77–101. https://doi.org/10.1007/978-1-0716-2918-5_5 Haery, L., Deverman, B. E., Matho, K...repository. GCaMP, a calcium indicator (biosensor, by Addgene’s categorization) was first developed in 2001....   Figure 2: Numbers of AAV tools, by category, available from Addgene as of 2023. A large... calcium and voltage sensors, are the broadest category of viral vector tools, which may help explain ...number of requests for vectors in the “controls” category, which includes things like viral vectors that...
  24. Tips for arabidopsis transformation

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    ...with a single insertion because it will segregate 3:1 in the T2 generation. You also have no control over... transgenic plants in the process.     References 1. Emami, S., Yee, M. and Dinneny, J. R. (2013) ‘A robust...transformation’, Plant Methods. BioMed Central, 2(1), p. 19. doi: 10.1186/1746-4811-2-19. PubMed PMID:...Agrobacterium tDNA insertion likely precipitated domestication of sweet potatoes (Kyndt et al., 2015)! It sounds...
  25. A New Optogenetic Tool Based on AraC Controls Gene Expression with Blue Light

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    ...level of expression needed for most applications.   Figure 1: With blue light, the VVD domains of... that dimerizes upon exposure to blue light (Fig. 1). Another blue light-inducible dimerization domain...in @nchembio Title: Bye bye L-arabinose drive. Dedicated to Edo, Armin and @KhammashLab. I hope you all...
  26. Antibodies 101: Avoiding the Mouse on Mouse Mess in IHC

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    ...following three strategies might help!     Figure 1: Species on species staining can be a problem because...same host species as your secondary antibody since 1) your secondary should not recognize Fab fragments... “species on species”) immunochemistry (IHC) applications an issue? The culprits are endogenous IgGs in...Partridge TA (1998). A New Blocking Method for Application of Murine Monoclonal Antibody to Mouse Tissue...
  27. Designing Your Chalk Talk for the Academic Job Interview

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    ...acceptable. Aims should be mechanistic, doable by 1-3 people in 1-5 years, and contribute to resolving the overarching...possible, do at least two full length practices (~1 h) and get feedback. It’s also helpful to practice...anticipated outcome, and payoff for each aim. Learn to communicate your story with only the most salient details...
  28. CRISPR 101: Which Cas9 Do I Choose for My CRISPR Experiment?

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    ...guide RNA (sgRNA), provided it meets two conditions:  1) The sequence is unique compared to the rest of the...bystander bases” if you choose this system.  Fig. 1: Cytidine deamination takes place on the free strand...temperature-controlled genome editing. Nat. Commun. 2017 81 8, 1–9 (2017).Walton, R. T., Christie, K. A., Whittaker... than ever to make precise, targeted genome modifications. Cas9 has been modified to enable researchers...instead.  Choosing a Cas9 for site-specific modifications Site-specific deletions and knockouts Some experiments...mutation at a specific site e.g., deleting the catalytic residue of a protein or knocking out a very small...flexibility as to where your sgRNA needs to be located and there may not be a NGG PAM site anywhere to...
  29. CRISPR 101: Homology Directed Repair

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    ...oligodeoxynucleotides)) are commonly used for smaller modifications (~1-50 base pairs). Small edits require as little...Easi-CRISPR was shown to increasing editing efficiency from 1-10% with dsDNA to 25-50% with ssODNs in mouse models...ribonucleoproteins. Quadros RM, et al. Genome Biol. 18(1); (2017). PubMed.  Additional Resources on the Addgene...pathways of DSBs, with a focus on repair for genome modification purposes. How does homology directed repair...specific mutations into the damaged DNA if these modifications exist in the template DNA. There are several... genome engineering world and made targeted modifications feasible and even easy. This targeted-break ...that can be harnessed by researchers for many applications. Your favorite Cas enzyme, a guide RNA to your...
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