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  1. Lab to Office Culture Shock

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    Blog Post
    ...opportunity to discover and evolve your transferable skills. Transferable skills are the non-technical skills...employee who's coming directly from grad school. The transition has been a bit rough for her (3 weeks in and ...there are any resources that can help with the transition.” The lab-to-desk-job culture shock is a real...scientist colleagues have as well. Making the transition from the bench can be jarring for the unprepared...resources out there for scientists making this transition. In this installment of the Addgene career guide...brief period of time, the only, person to know a brand new fact is often enough to keep a scientist going...formulate hypotheses and conduct experiments. You transfer liquids between tubes, look through microscopes...
  2. Bacterial Toxin-antitoxin Systems as Molecular Biology Tools

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    Blog Post
    ...required for hok translation. Here, Mok and Hok translation is coupled. Translation from the Shine-Dalgarno...more stable than the methyltransferase. When a plasmid is lost, the methyltransferase is degraded and/or...systems have been used as biological tools for a wide range of applications in molecular biology or in vivo ...ccdB gene die off and a higher percentage of transformants contain the ccdB-less construct. Other toxin-antitoxin...composed of restriction endonucleases and methyltransferases. Restriction endonucleases cleave DNA at ...specific nucleotide sequences. To counter this, methyltransferases add methyl groups to bases at specific nucleotide...or diluted as the cell grows resulting in the appearance of unmethylated sites in the chromosome. The ...
  3. GPCRs: How Do They Work and How Do We Study Them?

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    Blog Post
    ...different ligands, including hormones, neurotransmitters, photons or odorants, to elicit downstream signaling...seven-(pass)-transmembrane domain receptors, due to the seven alpha helices that transverse the cellular...cell membrane. Heterotrimeric G proteins are important molecular switches in signal transduction pathways...fusion to a receptor-transcription factor fusion. TEV protease cleave the transcription factor from the receptor...initiating signaling pathways in inflammation, and neurotransmission. These receptors can be activated by an array...cellular membrane. The receptor recognizes the appropriate ligand to activate the G proteins. It is estimated...parallel receptorome expression and screening via transcriptional output - TANGO) (Kroeze et al., 2015). PRESTO-TANGO...
  4. Enhancing CRISPR Targeting Specificity with eSpCas9, SpCas9-HF1, & HypaCas9

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    Blog Post
    ...increases when target DNA strand separation is stabilized (2,3). Stable strand separation is maintained...and therefore destabilize basal strand separation. This decreased strand separation combined with the weak... Figure 1: Strand separation and target DNA binding to the Cas9 nuclease. Stable strand separation is...the non-target strand and the HNH/RuvC groove, and interactions between the target strand and the gRNA....interactions : 1. Interactions between the non-target strand and a positively charged groove formed by the Cas9...nuclease domains 2. Interactions between the target strand and the gRNA (see figure below) Because off-target...by a technique for detecting genome-wide double strand breaks (BLESS), revealed that these mutants do ...
  5. Hot Biosensors 2022: Year-End Roundup

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    Blog Post
    ...new class of sensors for neuropeptides and neurotransmitters. Motivated to develop a biosensor for oxytocin...devised a “Modular fluorescence unit fused with TRansmembrane region-to-IntrAcellular loop linkers” (MTRIA...sensors based on GPCRs recognizing various neurotransmitters, neuropeptides and other ligands - almost ...kinetics and localization for imaging synaptic transmission. bioRxiv 2022.02.13.480251. doi: 10.1101/2022.02.13.480251...2022.02.13.480251 JEDI-2P voltage sensor The François St-Pierre lab and colleagues have developed a new...they observe fluorescence localizes to the plasma membrane only when the RTK is activated and the ITAM phosphorylated...relies on a change in localization to the cell membrane and not a direct change in the fluorescent properties...
  6. Antibodies 101: Normalization and Loading Controls for Western Blots

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    Blog Post
    ...errors like uneven pipetting or irregular membrane transfer. Figure 1: A loading control is a type...lies the linear detection range. Figure 4: The linear detection range of the assay is between the.... No pipetter is perfect, and proteins may not transfer precisely evenly across the entire blot. So how...directly correlate to protein abundance on your membrane, which would be directly reported by band intensity... in the loading control are due to loading and transfer errors — not to any factors from before the proteins...control points are outside of the linear detection range. As a result, they have almost the same value on...computational quantification. Outside the linear detection range, band intensity measurements become extremely susceptible...
  7. The Fluorescent Vegetables in Aptamer Soup

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    Blog Post
    ...quantify RNA transcription by RNA Polymerase III. By expressing Corn under promoters for transcripts uniquely... and orange fluorescent aptamers Corn was described in the same study as Red Broccoli and Orange Broccoli...fluoresce in the red and orange channels, respectively. Both Red Broccoli and Orange Broccoli are derived ...multiple derivatives of thiazole orange (TO) and fluoresces in the orange or red channel, depending on the...aptamers are used to track cellular processes by transforming cells with plasmids encoding aptamer-tagged ...tagging RNA sequences with an aptamer and RNA transcription by placing the aptamer downstream of a known...hydroxybenzylidene imidazolinone (DFHBI). DFHBI is membrane permeable and non toxic to cells. Because it rapidly...
  8. Plasmids 101: The Wide World of Natural Plasmids

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    Blog Post
    ...lateral”) gene transfer. Horizontal gene transfer can occur naturally through transformation (cellular uptake...? Plasmids 101: Transformation, Transduction, Bacterial Conjugation, and Transfection Resources on Addgene.org...environment), transduction (viral infection by bacteriophages), or conjugation (direct transfer from one cell...one popular method scientists use to promote transformation, but it isn’t just for lab specimens — there... evidence that lightning can also promote gene transfer in soil bacteria! (Demanèche et al., 2001) Beneficial...humans only noticed last century! Nevertheless, the transfer of plasmids carrying these genes between bacteria...plasmid are now used routinely in biotechnology to transform plant cells. Degradative plasmids: microbial hardiness...
  9. Adenoviral Vector Production and Troubleshooting

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    Blog Post
    ...produced at high titers, can accommodate large transgenes, transduce quiescent and dividing cells, and do not..., which results in the death of transduced cells and loss of transgene expression (Interestingly, the ...adenoviral genome. The genome itself is a linear double-stranded DNA of ~36kb, with inverted terminal repeats (...E3 regions and can accommodate up to 8.2 kb of transgene DNA. The second generation vectors are deficient...cloning capacity is limited to 8.2 kb, and in vivo transgene expression ceases relatively quickly due to immune... the E1 gene from the packaging cell line is transferred into the AdV by recombination. It is therefore...adenovirus is required to provide the viral proteins in trans. The Gutless AdV have generated high interest for...
  10. Synthetic promoter AAVs for cell-type specific expression in retinal cells

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    Blog Post
    ...mouse cell type specific transcription factor binding sites interspaced with random sequences.   Strategy...synthetic promoters. Legend: TSS: transcription start site. TFBS: transcription factor binding site. Image from...particular cell type is important not only for translational research, such as gene therapy, but also basic... using naturally occurring promoters to drive transgene expression, the Roska lab built synthetic promoters...conserved sequences that are upstream of the transcription initiation sites of at least two genes with ...designed using stretches of DNA that were transcriptionally active in retinal cell types in mice. ...synthetic promoter driving expression of the same transgene: an optogenetic reporter, channelrhodopsin, fused...
  11. Simple CRISPR-based Epigenetic Editing: dCas9-directed DNA Demethylation

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    Blog Post
    ...Tethering dCas9 to the histone acetyltransferase p300 or the DNA methyltransferase DNMT3A allows researchers...affect transcription independent of their enzymatic activity. They interact with transcriptional machinery...on DNA methyltransferase 1 (DNMT1) to copy methylation marks from parental to daughter strands of DNA....specifically edit methylation sites.  Step aside, transcriptionally active dioxygenase  When I started to work...by distinct proteins and result in unclear transcriptional consequences (Sprujit 2013). Enzymatic domains...in the genome and directly interacting with transcription machinery.   Well, I’ve got some good news...rounds of cell division, the original methylated strand is diluted to undetectable amounts: ergo, DNA demethylation...
  12. Antibodies 101: Flow Cytometry

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    Blog Post
    ...permeabilize the cell membrane to allow antibodies to pass through the cell membrane. Formaldehyde fixation...dye emits green, yellow and orange photons while PE emits yellow and orange photons. If FITC and PE were...sources that allow users to assess a cell’s size, granularity, and target protein composition. It is used for...target protein expression levels, assessing post-translational modifications, determining cell health, analyzing...a pressurized buffer called sheath fluid and transported through tubes or capillaries to a laser. As the...degree of internal complexity such as extensive membranes produces a greater SSC.  Protein expression, measured...targets, measured by fixing and permeabilizing membranes For intracellular protein targets, users must ...
  13. Deep Dive: Fixing and Permeabilizing for Immunofluorescence

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    Blog Post
    ...and membrane integrity (Fig. 2). For example, saponin interacts with cholesterol in cell membranes and...can lose membrane-associated proteins, but it is better at permeabilizing organellar membranes. Created...red lines), which maintains structural epitopes (orange region), but it can block epitopes hidden within...proteins that need a little help crossing cell membranes as they are not able to diffuse across natively...Permeabilization essentially punches holes in the cell membranes of your sample to allow antibodies better access...target is already on the extracellular side of the membrane, then this step may not be necessary. In fact,...and leaves many membrane-associated proteins in place. In contrast, Triton X-100 and Tween-20 are examples...
  14. New Optimized Genome-wide CRISPRko, CRISPRi, and CRISPRa Libraries

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    Blog Post
    ...prevent efficient transcription from sgRNA targets. CRISPRi is effective in a narrow range around the transcription...two sets of sgRNAs; A, the top 3 ranked sgRNAs, and B, the next 3 ranked sgRNAs. Dolcetto was able to discriminate...Cas9 derivatives. Unmodified Cas9 causes double stranded DNA breaks that commonly result in a complete ... lab selected sgRNAs in this optimal window and ranked them based on their optimized sgRNA rules and potential...gene expression, dCas9 can also be used for transcriptional activation. Activation of specific genes allows... strategies have been developed to recruit transcriptional machinery to dCas9 and its RNA directed binding...include RNA domains that recruit additional transcription factors. The Root and Doench labs utilized tracrRNAs...
  15. CRISPR 101: Cytosine and Adenine Base Editors

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    Blog Post
    ...the opposite strand). ABEs make an A to G change (or a T to C change on the opposite strand). Both are ...place on the free strand of DNA and converts a C to U without producing a double strand break. UGI = uracil...repair (HDR), the pathway for resolving DNA double-strand breaks (DSBs) preferred by researchers. Compared...are base transition editors: converting one purine base to the other or one pyrimidine base to the other...other. Figure 1: Base transition editors catalyze purine-to-purine or pyrimidine-to-pyrimidine base... indicate the change introduced to the opposite strand following base editing and DNA repair. Black arrows...BioRender.com. How does base editing work? Base transition editing requires three elements. They are, broadly...
  16. The MTA at Addgene

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    Blog Post
    ...Biological Material Transfer Agreement (UBMTA) is one of the most commonly used ones for transfers between academic...for more information. Happy transferring!    Many thanks to our Tech Transfer team members Maura Coughlin...Addgene, then you’ve been involved in the material transfer agreement (MTA) process. Even though this process...curious about the hows and whys of the material transfer agreement, read on!  What is the MTA?  An MTA...the creation of a standardized agreement on the transfer of biological materials in 1995: the UBMTA. Because...most academic and nonprofit institutes, the Tech Transfer department is responsible for managing research...plasmid with Addgene, your organization’s tech transfer office is sent a deposit agreement. The One-Time...
  17. Hot Plasmids - November 2023

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    Blog Post
    ...also incorporated LOV-Turbo into TransitID experiments.  Find TransitID plasmids here! These two developments...genetic cargo Optogenetic proximity labeling and TransitID Tracking cellular history with protein ticker ...in vitro and in vivo. Incorporating reverse transcriptase (RT) variants, PE6a and PE6b are 500–800 bp ...be tethered on the viral surface, expanding the range of targetable cell types. DIRECTED is compatible...37612276.   Optogenetic proximity labeling and TransitID By Mike Lacy Proximity labeling can identify protein...plasmids here! Next, Qin and Cheah et al. described TransitID, where two proximity labeling enzymes, TurboID...catalyzing the biotinylation of nearby proteins. B) TransitID uses sequential labeling by TurboID and APEX2 ...
  18. Viral Production at Addgene

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    Blog Post
    ...of Pennsylvania Vector Core. Transfections are performed using the transfer plasmid, a plasmid encoding...PCR with primers targeting the transfer plasmid used in the transfection. PCR products are analyzed by ...cell cultures are inspected for sterility. Transducibility Some viral vectors are tested in vitro and ...images).     Figure 2: AAV Pro cells were transduced with either pAAV-Ef1a-mCherry-IRES-Cre (55634...filtration through a 0.45 µm polyethersulfone (PES) membrane. The preparations are then aliquoted, frozen, ...from Wang et al., 2018). Briefly, 293T cells are transduced with serial dilutions of a lentiviral vector,...taken offline and discarded. Confirmation of the transfer plasmid Addgene uses a rigorous barcode matching...
  19. Tips for Using FRET in Your Experiments

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    Blog Post
    ...fused to the N-terminus of LSSmOrange pLSSmOrange-C1 Orange Mammalian Express a gene of interest fused...GFP variant) commonly used with mRuby2 pLSSmOrange-N1 Orange Mammalian Express a gene of interest fused...Bioluminescence Resonance Energy Transfer CRET= Chemiluminescence Resonance Energy Transfer    Interesting Articles...FRET, aka Fluorescence (Förster) Resonance Energy Transfer, technique which allows the detection of molecules...distance-dependent physical process by which energy is transferred non-radiatively from an excited molecular fluorophore... (the acceptor) by means of intermolecular long-range dipole-dipole coupling." The emission of the acceptor...fused to the C-terminus of LSSmOrange mRuby2 Red Mammalian Expresses mRuby2 (a RFP variant) commonly used...
  20. FLEx Technology and Optogenetics: Flipping the switch on gene expression with high spatial and temporal resolution

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    Blog Post
    ...flow of electric charges across cell membranes and maintain membrane potential in response to visible light...across the axon's membrane: once a certain number of positive ions crosses the cell membrane, a threshold ...rhodopsins enable ions to flow across the axon’s membrane, thereby controlling neural activity (Bernstein...the opsin into the correct orientation to be transcribed (Figure 2) (Sharma and Zhu, 2014). How does FLEx... optogenetic FLEx vectors in combination with transgenic animals or rAAVs expressing Cre under a specific...the mechanisms of sleep and anesthesia. In Cre transgenic mice, they targeted the dopamine (DA) neurons... vectors combined with the use of several Cre transgenic mice targeting different brain areas enabled ...
Showing: 321 - 340 of 986 results