Skip to main content
Addgene
Showing: 301 - 320 of 986 results
  1. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

    Type
    Blog Post
    ...the zeptomolar range while One-step-SHERLOCK has a sensitivity in the femto-aptomolar range. For more details...are designed, each binding to one strand of the reverse-transcribed target sequence that are present close...reverse transcription. This is then amplified by PCR using Taq Polymerase and then transcribed to provide...LED and an orange filter to detect fluorescence upon cleavage. Highlights: Reverse-transcribed RNA samples... Suresh from Iowa State University. Since its appearance, SARS-CoV-2 has spread to almost every part of... milliliter can be detected – in the zeptomolar range Time: ~1 hour Equipment required: 37°C water bath...amplified. RPA reactions also contain reverse transcriptase to produce cDNA. Isothermal amplification is...
  2. Tips for a 1st time AAV user (by a Rookie AAV user)

    Type
    Blog Post
    ...proteins to process a double-stranded intermediate into the single-stranded genome that's then packaged...viral replication; and 3) the transfer plasmid which encodes a transgene of interest that’s packaged into...XmaI restriction sites). Another way is to transform AAV transfer plasmids into bacterial strains, like NEB...Overview: The first step in packaging AAV is transfecting HEK293 cells with AAV packaging plasmids. The... into the virus. Two to five days after transfection, the AAV-containing cells and media are harvested...more details. Pro tips I’m not going to lie, AAV transfer plasmids are kind of a pain to work with. These...structures that are prone to deletion from the transfer plasmid. The good news is there’s a few simple...
  3. Viral Vectors 101: Inverted Terminal Repeats

    Type
    Blog Post
    ...containing transcription factor binding sites can increase transgene expression and transduction efficiency...as the gene that they package. In a transfer plasmid, the transgene is flanked by two ITRs, and the ITRs...modifications can drastically affect gene transfer efficiency and transgene expression (Zhou et al. 2017). For...these mutations can affect transduction efficiency and subsequent transgene expression. Replacing the ...nucleotide sequences that flank the ends of the single stranded DNA genome of AAV in the native virus. In an AAV... the feature its characteristic T-shape. The arrangement of the B-B’ and C-C’ palindromic sequences determines...efficiency (Shitik et al. 2023). Transgene expression can be altered by using ITR sequences from different AAV...
  4. Multiplexed Overexpression of Regulatory Factors (MORF) collection

    Type
    Blog Post
    ...Transcription factors (TFs) act as the gate keepers for gene expression, turning transcription on and... regulatory network. The transcription atlas and library The transcription factor library The human...lentiviral particles and used to transduce human embryonic stem cells. Transduced stem cells were differentiated...approximately 1,800 TFs, with >3,500 unique isoforms transcribed from these sites. The Zhang lab generated a comprehensive... contribute to differentiation, the Zhang lab transduced human embryonic stem cells with the viral TF ...differentiation outcomes as well as global transcriptional changes. Using this road map, and what was ... uncharacterized TFs is a useful finding. Transcriptional program changes from this screen successfully...
  5. Viral Vectors 101: The AAV Retrograde Serotype

    Type
    Blog Post
    ...neurons! Neurons are really cool because they can transmit information, for example, from one of the 180 ...associated virus (AAV) shows relatively low retrograde transport efficiency in most serotypes. Some viruses (e....e.g., rabies) naturally exhibit retrograde transport and can therefore perform retrograde tracing, but...efficiently infects neurons, directs high-level transgene expression, and has retrograde functionality to...genetically controlled function. By using AAVrg in Cre transgenic mouse lines, you can access and manipulate an...from the hippocampus to Broca’s area would be transduced (Fig 3B). These specific neurons could then be...requires high titers for efficient retrograde transport. For recombinase-dependent vectors, this can cause...
  6. Plasmids 101: Sequence and Ligation Independent Cloning (SLIC)

    Type
    Blog Post
    ...through transformation, so the cloned vector must be ligated. But in LIC, longer single-stranded overhangs...T4 polymerase (left branch); by annealing two separate PCR products (middle branch); or by incomplete ...step to retain products with single-stranded overhangs (right branch). The mixed PCR and incomplete PCR...overlapping regions of single-stranded DNA. But as long as the double-stranded region is long enough to hold...nicks easily repairable by the bacteria after transformation. LIC is a reliable cloning method, but it is... sequences (20–60 bp) on either end and single-stranded 5′ overhangs… but it doesn’t really matter if ...recombination intermediate to bacteria, so it can be transformed as-is into cells. The cells then get to work ...
  7. New Acoustic Reporter Genes: Ultrasound Imaging of Gene Expression

    Type
    Blog Post
    ...the transient cotransfection of the mARG plamsids into HEK293T cells using a chemical transfection reagent... These plasmids can be used directly in transient transfection in rtTA+ cell lines (such as HEK293-TETOn...into the genome by cotransfecting them with a plasmid expressing PiggyBac transposase. In rtTA-cell lines...engineering a cell line, cotransfect the mARG cassettes 2:1 (A:N-V) with PiggyBac transposase and outgrow the ... of replication (p15A) worked best under a wide range of inducer concentrations (0.1-1% L-arabinose) without...proteins. Excess gvpA plasmid added into the transfection mixture in HEK293T cells gave drastic improvement...improvement in expression. Stabilizing the gvpA transcript with WPRE reduced the number of copies of gvpA ...
  8. Advanced Uses of Cre-lox and Flp-FRT - A Neuroscientist’s View

    Type
    Blog Post
    ...concentration of FLEx vectors guarantees that most cells are transfected with all labeling plasmids and...PMCID: PMC2593125. 2. Buchholz, F, P O Angrand, and A. Francis Stewart. 1998. “Improved Properties of ... sites can lead to excision, inversion, and translocation of DNA in a similar fashion as between loxP ... has a temperature optimum of 37 °C (Buchholz, Angrand, and Stewart 1998). FLPe’s performance was further...in FLPO, which shows similar efficiency to Cre (Kranz et al. 2010). These differences in recombinase efficiency...-LDB domains of the fusions allowing Cre/FLP translocate to the nucleus where they exert their recombinase...brain? Cells of a specific brain area can be transfected by in utero electroporation. To achieve sparse...
  9. To Codon Optimize or Not: That is the Question

    Type
    Blog Post
    ...is codon usage important? Translation and protein synthesis relies on transfer RNAs (tRNAs). tRNAs bind...rate of translation and thus protein expression. In fact studies have shown that translational efficiency...on an organisms codon usage bias to increase translational efficiency and thus protein expression without...mammalian cells. This was the first codon optimized membrane protein expressed in mammalian cells. In this ...conformation, folding and stability, change post-translational modification sites and even affect protein function...Mauro and Chappell, 2014). Different rates of translation by different tRNAs, including those that exhibit...actually be critical for determining the rate of translation. The ribosome may slow and pause during elongation...
  10. Viral Vectors 101: An Introduction to AAV

    Type
    Blog Post
    ...therapies and in vivo laboratory experiments ranging from transient gene expression in a particular cell type... Figure 2: DNA rescue and transduction of a conventional single-stranded AAV (ssAAV) and a self-complementary...genome conversion in the transduced cell nucleus, the single-to-double stranded conversion of the DNA goes...structure can readily fold into transcriptionally active double-stranded form through intra-molecular annealing...Adeno-associated virus (AAV) is a single stranded, Parvoviridae DNA virus, packaged in a non-enveloped...hijack host cell machinery, and synthesize a second strand of DNA before expression of their cargo can begin...integrate into the host genome and therefore the transduced gene is episomal and does not divide and replicate...
  11. Plasmid Tools for Microbiome Studies

    Type
    Blog Post
    ...for broad or narrow range of microbial species. These also contain the RP4 transfer origin as well as a..., the ability to detect mRNA transcripts of toxins and other transcripts of interest is a benefit of this...the organisms present while sequencing of all transcripts gives clues into what the microbes are doing....followed by a reporter gene. The hairpin blocks translation by sequestering the RBS, but binding of the “...microbial community) reveals the RBS and allows translation of the reporter gene resulting in GFP signal....lacks genetic tools is the bee microbiome. Nancy Moran’s and Jeffrey Barrick’s labs at The University of... RSF1010 origin, an IncQ origin with broad host-range (Meyer, 2009). The vector retains the oriT for delivery...
  12. Rabies and Neuronal Tracing

    Type
    Blog Post
    ...generally are not transmitted to adjacent neurons via synapses (i.e., transmitted transsynaptically). This is ...retrograde transmission (Etessami et al., 2000, Wickersham et al., 2007). Thus, RABV transsynaptic spread ...replicate. Modified Rabies Virus: Converting a transsynaptic neuronal tracer into a monosynaptic (first order...subsequent cycles of viral replication and retrograde transmission occur, spreading the virus through higher and...higher order neural connections. While this transsynaptic spread is useful for neuronal tracing, it has...-dependent TVA to Cre-expressing neurons in a transgenic mouse line. By doing this, RABV expressing the...necessarily express EnvA unless it is supplied in trans. Monosynaptic RABV spread can be achieved by modifying...
  13. Mouse Modeling, Part 1: Genetically Engineered Mice

    Type
    Blog Post
    ...inducible gene expression. Transgenic and knockin mice As the name suggests, transgenic and knockin mice contain...their genome. While transgenic mice have the new gene construct incorporated randomly into the genome, knockin...Conversely, outbred strains were originally derived from random crosses between mice of uncharacterized backgrounds...several types of genetically engineered mice: transgenic mice, knockout mice, and mice with conditional...construct inserted at a specific site. To generate a transgenic mouse, microinjection of DNA or infection with...Non-homologous recombination incorporates this DNA randomly into the mouse genome. In contrast, knockin strains...animal for gestation. Nucleases that induce double-stranded DNA breaks, such as ZFN and TALEN, can used to...
  14. Viral Vectors 101: Voltage Indicators

    Type
    Blog Post
    .... They can be targeted to the plasma membrane to measure membrane potential and can also be directed to... the membrane), the voltage sensing component (i.e., rhodopsin naturally resides in the membrane), or ... of voltage gated ion channels all depend on transmitting and sensing electrical potential. Thankfully... want to monitor the voltage change across the membrane of cardiac cells. Similarly, neuronal signaling...propagated through multiple cells to do things like translate perceived signals to physical actions. Understanding...rhodopsin proteins were initially evolved for ion transport, not fluorescence, they are not nearly as bright...sensors contained a FP that localized to the plasma membrane due to the addition of several targeting domains...
  15. Plasmids 101: Multicistronic Vectors

    Type
    Blog Post
    ...discovered in positive single-stranded RNA viruses to allow for the efficient translation of multiple genes from...Elements Translation in eukaryotes usually begins at the 5’ cap so that only a single translation event ...scientists use a multitude of techniques including co-transfection of two or more plasmids, the use of multiple...Unlike promoters which will create unique mRNA transcripts for each gene that is expressed, multicistronic...your gene as they are both derived from the same transcript. Of course multicistronic vectors do not have...from a single transcript. The two strategies most widely incorporated into plasmids for research purposes...Entry Site (IRES) to allow for initiation of translation from an internal region of the mRNA. In the ...
  16. Rewiring Metabolic Circuitry with CRISPR RNA Scaffolds [Video]

    Type
    Blog Post
    ...recent paper, "Engineering Complex Synthetic Transcriptional Programs with CRISPR RNA Scaffolds." Adam has...visualize the concepts discussed in the paper. The transcriptional control of multiple loci is deftly coordinated...cerevisiae with few techniques that are easily transferrable across host species or metabolic pathways. A...CRISPR-based RNA scaffolds to mimic natural transcriptional programs on multiple genes. Modifying the ...synthetic RNA scaffolds that can recruit various transcriptional regulators (Zalatan et al. 2015).  These scaffolds...nucleotide sequence then subsequently recruit a transcriptional regulator to modulate expression at that locus...expression levels dependent upon the type of transcriptional regulator or the number of designed scaffold...
  17. CRISPR 101: Ribonucleoprotein (RNP) Delivery

    Type
    Blog Post
    ...:     Cells must be amenable to transfection or viral transduction     Appropriate promoters must be...expression     The requirement for Cas9 transcription and translation delays editing What are Cas9-gRNA ... studies in cells that are difficult to transfect or transduce. While using Cas9-gRNA RNPs may require...site of interest. This is commonly performed by transfecting cells with a plasmid, such as PX459, which encodes... often be used in cells that are difficult to transfect, such as primary cells. Using RNPs can also alleviate... are detectable at high levels shortly after transfection, and are quickly cleared from the cell via protein...from Alex Schier’s Lab. gRNAs can be in vitro transcribed from ssDNA, which can be generated by commercial...
  18. FlipGFP, a novel fluorescence protease reporter to study apoptosis

    Type
    Blog Post
    ...contains 11 β-strands and one central ɑ-helix that can be split into 3 parts: (1) β-strands 1-9 (β1-9) and... and the one ɑ-helix, (2) β-strand 10 (β10), and (3) β-strand 11 (β11). Each part contains components ...developed, such as the Forster resonance energy transfer (FRET)-based executioner caspase reporters. In...need a protease reporter that has a large dynamic range and high brightness. The Shu Lab from UCSF designed...However, the lab wanted to increase the fluorescence range to better study the spatio-temporal dynamics of ...GFP (GFP1-9 and GFP10-11) by flipping a single β-strand of GFP, hence the name FlipGFP. FlipGFP increases...from β1-9 they will rapidly recombine with β1-9 strands nearby resulting in fluorescence within tens of...
  19. CRISPR 101: Multiplex Expression of gRNAs

    Type
    Blog Post
    ...humanized wt Cas9, dCas9 (transcriptional repressor), and dCas9-VP64 (transcriptional activator)-containing...Multiplexing from a single transcript You can also multiplex gRNAs via a polycistronic transcript. Rather than being...being transcribed from different promoters, the gRNAs are transcribed together and are flanked by specific...simultaneously. Vectors for both transient expression and Agrobacterium-mediated transformation are available. For ...system for processing a continuous multi-gRNA transcript, each gRNA must be expressed from its own promoter.... But that doesn’t mean you have to clone and transfect multiple promoter-gRNA constructs in order to ... Cas9, D10A nickase mutant (Cas9n), dCas9 (transcriptional repression), and Fok1-dCas9 (dimeric nuclease...
  20. Sonic Hedgehog? Sleeping Beauty? Learn About the Genes Behind Addgene’s Conference Room Names

    Type
    Blog Post
    ...but also a biological transposon system. Sleeping Beauty is a synthetic transposon system that can be used...reconstructed a transposase system based on the naturally mutated and non-functional transposase gene found...resurrecting this transposon system? Scientists can use Sleeping Beauty transposons as a non-viral system...Addgene recently moved to our brand new location, with more space to grow and help scientists share resources...you can use to study these genes! Groucho, a transcriptional co-repressor The first conference room, that...Addgenies, was named after the protein Groucho, a transcriptional co-repressor important in development. Groucho.... It binds to a specific set of DNA-binding transcription factors to repress the expression of genes primarily...
Showing: 301 - 320 of 986 results