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Showing: 241 - 260 of 862 results
  1. Viral Vectors 101: Inverted Terminal Repeats

    Type
    Blog Post
    Published
    Oct. 19, 2023, 1:15 p.m.
    ...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...efficiency (Shitik et al. 2023). Transgene expression can be altered by using ITR sequences from different AAV...Most ITR sequences are from AAV2 because they demonstrate high promoter activity (Earley et al. 2020), ...
  2. Optimizing Donor DNA for Enhanced CRISPR Genome Editing

    Type
    Blog Post
    Published
    March 24, 2016, 2:30 p.m.
    ... of the four strands of the cleaved duplex, while the fourth strand (the released strand in Figure 1 below...discovered that single stranded donor DNA: Complementary to the released strand, 127bp in length, With...single or double stranded donor DNA with other design parameters. Example single stranded donor DNA and ...biological process in detail often suggests new strategies to manipulate that process. We began our research...investigations into the release of DNA post-cut. Using substrate DNA labeled on both sides of the break, we determined...presented in Figure 2. Figure 2: Single-stranded donor DNA interaction with the Cas9-DNA duplex...replacement without cutting Our in vitro results also demonstrated that catalytically inactive dCas9 produced a...
  3. A Conference By Postdocs For Postdocs: Future of Research

    Type
    Blog Post
    Published
    Sept. 2, 2014, 3:05 p.m.
    ...of scientist training in the US and around the world. There are rumors that we are training too many scientists...few of these trainees are sufficiently prepared during their 6-12+ (!) years of training to get jobs. ...developing transferable skills to enable pursuit of these diverse opportunities after training. One of the... examples of science trainees taking a proactive role in their non-bench training. Grad students at Washington...academic administrators who are finding ways to provide new types of career preparedness training for their...the way we view the graduate school and postdoc training years. There is no doubt that there are too many...academia. Certainly funding for academic research and training is getting tighter and competition is fierce. ...
  4. MXS Chaining

    Type
    Blog Post
    Published
    Feb. 7, 2017, 3:30 p.m.
    ...constructs to visualize cell cycle dynamics, titrate inducible transgene expression, or a variety of other clever...throughput cloning strategies There are several high-throughput cloning strategies available for assembling...PubMed PMID: 25909630. PubMed Central PMCID: PMC4409215. 7. Swartz MN, Trautner TA, Kornberg A. Enzymatic ...incorporate each element into the final construct. This strategy can be used to build vectors with diverse functions...containing a unique fluorescent protein with minimal spectral overlap between them (Table 1). In each construct...expression) and a polyA signal (to terminate transcription) and the four constructs were then combined ...suited for particular downstream applications. The tradeoffs between various cloning methods are listed in ...
  5. Fluorescent Proteins 101: Green Fluorescent Protein (GFP)

    Type
    Blog Post
    Published
    May 15, 2014, 3:33 p.m.
    ...detect a variety of intracellular conditions, including ion (such as Ca2+) concentrations and pH, using a ...Developmental/transgenic uses: Because of its stability, GFP can be used in lineage tracking capacities ...reporter for DNA double strand break repair, and to label pathogenic intracellular microbes to visualize...spontaneously and without additional co-factors, substrates, or enzymatic activity – it only requires the...folding at 37C, reduces aggregation at high concentrations T203Y Red-shifts the wavelength (yellow derivatives...K26R, Q80R, N146H, H231L, (and probably others) Neutral mutations    A multitude of applications Due...backbones for constructing fluorescent fusions. Transcription Reporter: Placing GFP under the control of a...
  6. Viral Vectors 101: Optogenetic Tools

    Type
    Blog Post
    Published
    June 27, 2023, 1:15 p.m.
    ...control than is achieved by traditional pharmacologic methods. A number of strategies have been developed for... in the extracellular domain which activates the native signaling cascade of the intracellular part of...and Ca++ to passively enter the cell with the concentration gradient to depolarize it (Nagel et al., 2003...pumps that pass ions (Cl-, H+, Na+) against the concentration gradient and hyperpolarize the cell (Mattis ...activation by light showing ions flowing with the concentration gradient, and of activation inhibitory (ArCH...ArCH) proton pump passing ions against the concentration gradient. Created with BioRender.com.   Opto-G-protein...GPCR) regulate cellular function through multiple intra-cellular signaling cascades. Optical methods for...
  7. Plasmids 101: Dimers and Multimers

    Type
    Blog Post
    Published
    Jan. 10, 2023, 2:15 p.m.
    ...size, multimers may exhibit reduced transformation and transfection efficiency compared to the monomeric...1981). E. coli strains such as DH5α, HB101, NEB Stable, Stbl3, etc., are recA- mutant strains, and therefore... You can then gel extract the linearized band, ligate the plasmid, and re-transform the ligated plasmid... Elfinger M, Hartl D, Rudolph C. Transgene expression of transfected supercoiled plasmid DNA concatemers...multimeric forms (e.g. concatemers, dimers, trimers, tetramers). Since then, multimerization has been observed...the repeated plasmid sequence, giving greater concentration of cut DNA without changing the size. As a result...   Grow plasmids in recombinase-deficient strains Since plasmid multimerization is caused by homologous...
  8. Viral Vectors 101: Viruses as Biological Tools

    Type
    Blog Post
    Published
    March 21, 2023, 1:15 p.m.
    ...RNA cargo into their targets makes them attractive and tractable tools for genome engineering. Scientists... Packaging Capacity (>8kb) High Transduction Efficiency Transient Gene Expression High Immunogenecity...alternatives? Well, for one they have a high transduction efficiency and can effectively infect a wide...of cell types that are typically ‘difficult to transfect’, such as primary cells. They can also be directly...organisms. Finally, viral delivery is typically straightforward across applications, while electroporation ...derived from viruses that infect people in nature, extra safety measures, like replication incompetent viral...through nuclear localization signals which can traffic their viral particles inside the nucleus, without...
  9. Fluorescent Proteins 101: Aptamer Fluorophores

    Type
    Blog Post
    Published
    April 11, 2017, 2:30 p.m.
    ...fluor. Transcribing and translating a protein fluorophore also takes time - bypassing translation altogether...expression strategies.” Chem Biol. 2015 May 21;22(5):649-60. PubMed PMID: 26000751. PubMed Central PMCID: ... PubMed Central PMCID: PMC3279232. 10. Song, Shiping, et al. “Aptamer-based biosensors.” TrAC Trends in...have used antibodies for diagnostics know how frustrating it can be to get a “bad batch”); Customizable...help reduce such background, thereby improving traditional visualization techniques. In addition, their ...biosensors. Aptabeacons Fluorescence resonance energy transfer (FRET) technology has been studied and used in...fluorescence-activated cell sorting (FACS) of E. coli transformed with aptamer libraries, the Jaffrey group selected...
  10. CRISPR-mediated Plant Base Editors

    Type
    Blog Post
    Published
    Jan. 3, 2019, 1:35 p.m.
    ...72 hours post-transformation/transfection in a transient assay. For stable transformation, regenerated ...Agrobacterium-mediated transformation. We also constructed smaller vectors suitable for transient assays using ...double-stranded DNA cleavage." Nature 533.7603 (2016): 420. PubMed PMID: 27096365. PubMed Central PMCID...creates a nick in the DNA by cutting only a single strand, dramatically reducing the likelihood of detrimental...of the desired T-A base pair. Figure 1: Transition mutation (C>T, G>A, A>G, and T>C) installation...deaminases (ecTadA), fused it with dCas9, and transformed it into E. coli harboring the defective CamR ...TadA*) that satisfactorily accepts DNA as its substrate (see figure 2).          The artificially evolved...
  11. Four Base Editing Reporters to Monitor and Enrich Editing in Real-time

    Type
    Blog Post
    Published
    July 7, 2020, 1:15 p.m.
    ...reporter of transfection, which only report the efficiency of plasmid delivery to a cell. In contrast, TREE ... affecting protein translation of different reporter proteins. Protein translation requires the start ...compared to CRISPR/Cas9 edits that rely on double strand DNA breaks. Due to this inefficiency it is crucial...At the same time Cas9n cleaves the opposing DNA strain which results in two DSBs that can be repaired ...constitutively expressed to identify successfully transfected cells. C-to-T editing by the APOBEC-Cas9 editosome...that results in the restoration of fluorescence. Transient reporter for editing enrichment (TREE) The Wang...Wang and Brafman lab developed a transient reporter for editing enrichment (TREE) to purify single base...
  12. Hot Plasmids Spring 2024

    Type
    Blog Post
    Published
    May 23, 2024, 1:15 p.m.
    ...RNA polymerase III transcript, the sgRNAs were encoded on the lentiviral minus strand in the 3’ LTR. These... Figure 6: Illustration of split fluorophore assay to test reconstitution via mRNA trans-splicing. A ... with tRNAs, which are cleaved out of the RNA transcript by endogenous processing enzymes (Figure 1). ...including modifications to the Cas9 or reverse transcriptase enzymes, inhibition of host cell proteins, and...(Figure 3).      Figure 3: HeLa cells transduced with SARS-CoV-2 nucleocapsid protein (Plasmid...modification of microglial immune cells is critical for central nervous system research; however, microglia are...are notoriously resistant to viral transduction. Through in vivo screening of human promoters, the Zhang...
  13. Important Considerations in Optogenetics Behavioral Experiments

    Type
    Blog Post
    Published
    Oct. 1, 2015, 2:30 p.m.
    ...examples I’m personally interested in include: intracranial self-stimulation (ICSS) and place preference... a behavioral experiment in which an animal is trained to “freeze” upon anticipation of a mild electric...(viral expression, efficiency of laser light transmission to the target neurons, appropriate stimulation...mistakes. The easiest way to learn optogenetics is straight through the source - find a lab within your own...optogenetics is performed in this species. However, transgenic rat technology is improving and may one day reach... reach the sophistication of mouse transgenics. Everything that has been described is intended for the...References 1. Stuber, Garret D., et al. "Excitatory transmission from the amygdala to nucleus accumbens facilitates...
  14. Enhancing CRISPR Targeting Specificity with eSpCas9, SpCas9-HF1, & HypaCas9

    Type
    Blog Post
    Published
    Dec. 16, 2015, 3:30 p.m.
    ...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 ...
  15. Three Key Considerations for Precise Neuronal Targeting Using AAV Technologies

    Type
    Blog Post
    Published
    Nov. 27, 2019, 2:03 p.m.
    ... cell types. Specific transgene expression can be also achieved in nontransgenic animals by using cis ...population.  Combinatorial strategies can also be used for retrograde tracing: visualizing neurons that...delivery by increasing transgene cargo capacity, enhancing anterograde transport efficiency, and engineering...and Development workshop aimed at brainstorming strategies for using combinations of AAV-based molecular... cell of interest: AAV tropism and route of administration AAV tropism is defined by the viral capsid ...proteins that determine the AAV serotype. During transduction, the viral capsid proteins bind to the target...serotype used for a specific cell type. Find some transduction characteristics of select AAV serotypes in Table...
  16. Finding Your Science Policy Path

    Type
    Blog Post
    Published
    Sept. 22, 2020, 1:15 p.m.
    ...STPF) at the Veterans Health Administration, I could never get one straight answer about what science policy...early demonstrates not only your interest to future positions, but will also make your transition from ...Technology Policy Fellow at the Veterans Health Administration. “But, seriously, what even is science policy...first few decades of my life following a very straightforward conveyor belt from high school to college to...professionals that entered the field from a more traditional policy background, learning the science part ... or LinkedIn to learn more about their career trajectory. If there’s one thing everyone loves, it’s talking...through convening activities, formal lobbying, or strategy setting.  The “little p” policy is non-governmental...
  17. Fluorescent Proteins 101: Fluorescent Biosensors

    Type
    Blog Post
    Published
    May 18, 2017, 2:30 p.m.
    ...enzyme or transcriptional activation, conformational changes, translation, and protein translocation. Targeting...be expressed. Are you looking at an intracellular or extracellular molecule? By fusing a biosensor to ...biosensor, you first need to decide the best way to track or measure the process you’re interested in. Depending... reaction, you could measure consumption of a substrate OR production of a product OR enzyme activity....biosensors Addgene has many sensors that measure the concentration of small molecules like arabinose or hydrogen...fluorescent protein fused to a domain that senses the concentration of a given ion - we’ll use calcium biosensors...triggers CaM/M13 interaction that increases FRET transfer between the fluorescent proteins. FRET is highly...
  18. Plasmids for Endogenous Gene Tagging in Human Cells

    Type
    Blog Post
    Published
    April 6, 2017, 1:02 p.m.
    ...would be transcribed and translated. For an N-terminally tagged protein, we used the same strategy, inserting... copy. The coding sequence for GFP is transcribed and translated along with the gene, producing both a...destroyed by CRISPR/Cas9 during transfection. Making the double strand break and introducing the tag through...Science Plasmid Collection Fluorescent tagging strategy Figure 1: Gene editing is the addition ... plasmid Figure 2: Donor plasmid design strategy. A donor plasmid contains 1 kb homology arms matching...base pairs on each side, in fact. Later, when we transfect the cells, these large regions of homology enable...directed repair (HDR) process following the double strand break CRISPR/Cas9 makes at the target site. The...
  19. Quickest Way to Deposit Plasmids: The Deposit Spreadsheet

    Type
    Blog Post
    Published
    March 8, 2017, 3:15 p.m.
    ...any of these standard strains, choose other, indicate strain in the “Growth Strain Other” field, and contact...easy — our tech transfer team will communicate with your organization’s technology transfer office or other...room temperature. Growth Strain Please indicate which growth strain Addgene should propagate your...Survival strain. For plasmids that contain the R6Kγ origin of replication, choose the Pir1 strain. If your... you send your samples to Addgene pre-transformed in this strain. Hazardous If the plasmid will ... Send plasmid information to Addgene Material Transfer Agreement (MTA) approval  Send plasmids to Addgene...nourseothricin (clonNat), spectinomycin, streptomycin, tetracycline, combinations of the above, or other. High...
  20. CRISPR 101: Engineering the Plant Genome Using CRISPR/Cas9

    Type
    Blog Post
    Published
    Oct. 11, 2016, 2:30 p.m.
    ...certainly possible to select for desirable traits using traditional plant breeding approaches, these techniques... cells. In contrast to homology directed repair, these methods do not involve double strand break (DSB...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...
Showing: 241 - 260 of 862 results