We narrowed to 801 results for: Ran
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TypeBlog PostPublishedOct. 8, 2024, 1:15 p.m....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...
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Synthetic promoter AAVs for cell-type specific expression in retinal cells
TypeBlog PostPublishedMarch 12, 2020, 1:15 p.m....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... -
Selecting Your Plasmid Purification Kit
TypeBlog PostPublishedMay 27, 2025, 1:15 p.m....BioRender.com. Transformation Grade DNA (low quality/low quantity) – Bacterial transformation protocols require...highest-competency cells you will still struggle to get transformants if the plasmid you are using is completely degraded...important reactions like PCR or restriction digests. Transfection Grade DNA (high quality/high quantity) – Depending...Depending on the experiment, mammalian cell transfections can require quite large amounts of DNA (easily...carry-over into the eluate, while other kits are guaranteed to yield endotoxin-free DNA. Once you know the...kits are designed to accommodate specific volume ranges of culture as their input (Table 1). When you feel...addition to standard purification kits, there’s a range of specialty kits available for plasmid purification... -
Deep Dive: Fixing and Permeabilizing for Immunofluorescence
TypeBlog PostPublishedAug. 30, 2022, 1:15 p.m....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... -
New Optimized Genome-wide CRISPRko, CRISPRi, and CRISPRa Libraries
TypeBlog PostPublishedOct. 4, 2018, 12:44 p.m....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... -
CRISPR 101: Cytosine and Adenine Base Editors
TypeBlog PostPublishedFeb. 13, 2025, 2:15 p.m....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... -
The MTA at Addgene
TypeBlog PostPublishedJuly 23, 2024, 2:17 p.m....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... -
Hot Plasmids - November 2023
TypeBlog PostPublishedNov. 14, 2023, 3:35 a.m....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 ... -
Viral Production at Addgene
TypeBlog PostPublishedOct. 24, 2023, 1:15 p.m....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... -
Tips for Using FRET in Your Experiments
TypeBlog PostPublishedNov. 5, 2014, 3:41 p.m....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... -
An “elegans” Approach to Better CRISPR/Cas9 Editing Efficiency
TypeBlog PostPublishedDec. 17, 2020, 1:30 p.m.... technologies have transformed the palette of experiments possible in a wide range of organisms and cell...genomic locus (CRISPR-ChAP-MS) could further transform the range of experiments imaginable in C. elegans. ...Genome Editing with Short Single-Stranded and Long, Partially Single-Stranded DNA Donors in Caenorhabditis...at 25 ºC. This method resulted in efficiencies ranging from 11-100% of F1 animals carrying precise knock-ins...This stringent selection allowed me to optimize a range of editing parameters: oligo repair templates with...with homology arms of 35-80 bp, and DNA double-strand breaks up to 54 bp from the desired insertion site..., they devised guidelines for designing single-stranded repair templates (Farboud et al., 2019). The... -
FLEx Technology and Optogenetics: Flipping the switch on gene expression with high spatial and temporal resolution
TypeBlog PostPublishedOct. 17, 2019, 12:28 p.m....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 ... -
Protein Tagging with CRISPR/Cas9: A Conversation with Mendenhall and Myers
TypeBlog PostPublishedJuly 28, 2015, 2:30 p.m.... pair has focused considerable attention on transcription factors, starting with an established method... relies on antibodies to recognize and bind transcription factors directly, but that’s a slow-going process...ENCODE project is to look at all 1,500 or 1,600 transcription factors and figure out where they bind to the... ChIP-seq, but it’s really hard for lots of transcription factors. Our groups got together to adapt CRISPR...big difference. We can now look at many more transcription factors. Addgene: How does the system work? ...second plasmid to target an epitope tag onto the transcription factors. By the way, you can actually use this... in all kinds of different assays, not just transcription factors. The second vector is a homology directed... -
Plasmids 101: Cre-lox
TypeBlog PostPublishedJan. 13, 2015, 3:47 p.m....A double-strand DNA break occurs within the core spacer of each loxP site and the two strands are ligated...maintained). Translocation: If the sites are on separate DNA molecules, a translocation event is generated... expression – placing a series of transcriptional and translational termination features with loxP sites... pun) specific, targeted DNA modifications in transgenic animals, embryonic stem cells, and/or tissue-...that there is virtually no chance of it occurring randomly. Therefore, inserting loxP sites at deliberate...Inversion: If the loxP sites are on the same DNA strand and are in opposite orientations, recombination...research tool, especially in the field of mouse transgenics. A few of the most common uses are listed below... -
Hot Plasmids: Summer 2024
TypeBlog PostPublishedAug. 27, 2024, 1:15 p.m....which ensures the editor will only be transiently present in transduced cells, limiting off-target editing... dCas9 fused to a DNA methyltransferase — that can drive lasting transcriptional silencing (Nuñez et al...virus-like particles (eVLPs) offers an option to transduce cells directly with ribonucleoprotein cargo. eVLPs...attB/P recombinase landing sites on opposite DNA strands. When the prime editor releases the DNA, the two.... (2024). Engineered virus-like particles for transient delivery of prime editor ribonucleoprotein complexes...Histone tail for Autoinhibition Release of Methyltransferase (CHARM), with several advantages over the ... Rather than overexpressing an exogenous methyltransferase for epigenetic silencing, which can be toxic... -
Fluorescent Proteins 101: GFP Fusion Proteins - Making the Right Connection
TypeBlog PostPublishedApril 9, 2019, 1:13 p.m....et al., 2018). Unbiased, random insertions can be generated with a transposon-based strategy (Sheridan...fluorescent fusion proteins: random insertion of GFP with an in vitro transposition reaction." BMC neuroscience... This type of interference is known as steric hindrance. For instance, GFP may occlude catalytic sites...sites or motifs that are necessary for post-translational modifications. Despite these potential issues...targeted to the endoplasmid reticulum based on the appearance of OSER whorls. This assay is quantitative and...various fluorescent proteins (Botman et al, 2018; Cranfill et al, 2016; Lambert, 2019). These characteristics...applications, many were concerned with steric hindrance by the fluorescent protein. Thus, scientist began... -
CRISPR 101: Engineering the Plant Genome Using CRISPR/Cas9
TypeBlog PostPublishedOct. 11, 2016, 2:30 p.m....variants (hereafter referred to as Cas9) and a single stranded guide RNA (gRNA) is sufficient to modify the genome...variants have been created in an effort to increase translation in a particular plant species or cell type (Belhaj...CRISPR components can be expressed stably or transiently depending on the delivery method and cell type...CRISPR components can be delivered and expressed transiently using a standard detergent, Polyethylene Glycol... More information on Agrobacterium-mediated transformation can be found in this blog post. The pDGE Dicot...Simplified schematic of agrobacterium-mediated transformation in plant cells. Agrobacterium tumefaciens can...plant genome. B) The Ti plasmid and helper are transformed into agrobacterium tumefaciens and exposed to... -
Evolution of Lab Techniques
TypeBlog PostPublishedJune 21, 2016, 2:30 p.m....into smaller pieces, run on a gel, and transferred to a membrane for analysis through hybridization of ...researchers generating transgenic animals may choose Southern blotting to screen founder transgenic animals for ...techniques used to generate transgenic mouse lines, such as BAC transgenic or traditional knockins/knockouts... control sample. Southern blotting applications range from confirming the results of cloning or knockout...for the inserted transgene because Southern blots have a lower false positive rate than real-time PCR (4...hydroxyl group required for the extension of a DNA strand (8). Adding a small amount of a single radiolabelled...regular nucleotides results in the synthesis of DNA strands of all possible lengths because extension is terminated... -
Evolution of Brainbow: Using Cre-lox for Multicolor Labeling of Neurons
TypeBlog PostPublishedApril 24, 2015, 2:39 p.m....proteins, which are directly trafficked to cell membranes. Membrane trafficking of farnesylated derivatives enables...Brainbow-3.0, but with mOrange2, EGFP and mKate2 as the fluorophores; mOrange2 is the default state. In... virus post-transcriptional regulatory element (WPRE), commonly used to increase transgene protein levels...fluorescent proteins: RFP (red), YFP (yellow) and M-CFP (membrane tethered cyan). Without Cre recombination, RFP...first fluorescent protein in the construct, OFP (orange), is expressed when Cre is absent; stochastic Cre...This system differs from Brainbow-1.0 in that transient Cre recombination is required to prevent constant... both fluorescence and sequence overlap (coral mOrange2, jellyfish EGFP, and sea anemone mKate2.) They... -
Fluorescent Proteins 101: Introduction to FRET
TypeBlog PostPublishedJune 27, 2017, 1:03 p.m....this FRET you speak of? Förster Resonance Energy Transfer (FRET) was originally described by Theodor Förster...alternative acronym Fluorescence Resonance Energy Transfer. Unlike the typical excitation and emission of...excited fluorophore, FRET involves a non-radiative transfer of energy (i.e. no emitted photons) from the excited...excitation by absorption of a photon 2. Energy transfer from the excited donor directly to the acceptor...the acceptor fluorophore. Otherwise the energy transferred from the donor will not be able to excite the...other and be oriented appropriately for energy transfer via dipole-dipole interaction. The efficiency ...biological processes occur within the typical FRET range, FRET efficiency is used to infer an interaction...