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Showing: 41 - 60 of 340 results
  1. Prime Editing: Adding Precision and Flexibility to CRISPR Editing

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    Blog Post
    ...strand during mismatch repair   ✓   ✓ ~ ~ ~ Transiently co-express mismatch repair inhibitor...DNA. The heteroduplex is resolved by the cell’s mismatch repair system, and more recent prime editing innovations... innovations have improved the odds of mismatch repair favoring the edited strand. The first iteration...to PE1 (Anzalone et al., 2019). PE3: Resolving mismatched DNA to favor the edit Once the prime editor incorporates...incorporates the edit into one strand, there’s a mismatch between the original sequence on one strand and...relies on the PE2 enzyme. PE4 and PE5: Engineering mismatch repair Even in PE3 and PE3b, prime editing efficiency...CRISPRi screen, the Liu lab discovered that cellular mismatch repair contributed to a large number of unintended...
  2. 27 Hot Plasmids from 2016

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    Blog Post
    ...  Superglue proteins with SpyTag/SpyCatcher and SnoopTag/SnoopCatcher The development of recombinant DNA...alternating the use of the SnoopTag/SnoopCatcher and SpyTag/SpyCatcher pairs. In order to improve the ease...MBPx-SpyCatcher construct. This construct is used to produce a maltose binding protein/SpyCatcher fusion...of larger fusions through SpyTag/SpyCatcher and SnoopTag/SnoopCatcher linkages. Once all of the desired...and directional protein fusion, with a SpyCatcher-SnoopCatcher linker remaining between each protein unit...to be expressed and the native methyl-directed mismatch repair (MMR) system needs to be repressed in the...engineered a new peptide/protein pair, SnoopTag/SnoopCatcher, that can be used to irreversibly link desired...
  3. Genetic Code Expansion

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    Collection
    ...a previously established protocol, make sure to match the growth medium, ncAA concentration, and the cell...
  4. Plasmid Cloning by PCR

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    Blog Post
    ...Forward Primer will use the sequence 5'-ATGTGGCATATCTCGAAGTAC-3' for the region that binds the ORF and...primer, making our Forward Primer 5'-GAATTCATGTGGCATATCTCGAAGTAC-3'. Many restriction enzymes do not cut...final Forward Primer sequence of 5'-TAAGCAGAATTCATGTGGCATATCTCGAAGTAC-3'. For the Reverse Primer, the design...of the ORF, including the stop codon (5'-TGGCATATCTCGAAGTACTGA-3'), then adding NotI (GCGGCCGC) and then.... This gives us a sequence of 5'-TGGCATATCTCGAAGTACTGAGCGGCCGCTAAGCA-3' (30bp with 18bp of homology to...chose for our reverse primer (5’-TGGCATATCTCGAAGTACTGAGCGGCCGCTAAGCA-3’) into this calculator we get a...Addgene Blog Learn About Other Cloning Techniques Catch Up on All Things Plasmid with Our Plasmids 101 Series...
  5. Screening for Successful Genome Editing with Digital PCR

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    Blog Post
    ...projects. Most researchers instead turn to so-called “mismatch nuclease” assays (e.g. Surveyor® or T7E1) for ...technology. Digital PCR has several advantages over mismatch nuclease assays that will be elaborated below....several major advantages over the commonly employed mismatch nuclease assays. Sensitivity: Less than 20 ng...plate without prior quantification. Comparatively, mismatch assays require between 200 and 500 ng of purified...about 5% mutant targets have been reported for mismatch nuclease assays (2, 6, 7). Ability to distinguish...complete functional knockout of your target gene. Mismatch nuclease assays are completely “blind” to this.... & Pollet, N. Comparison of T7E1 and surveyor mismatch cleavage assays to detect mutations triggered ...
  6. Cpf1 Update: Comparison to Cas9 and NgAgo

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    Blog Post
    ...pair gRNA-target mismatches on modification by AsCpf1 (red) or LbCpf1 (blue). Mismatch positions are indicated...with single and double mismatches throughout the 23-base sequence. Double mismatches ablated Cpf1 activity...bases 19-23). Cpf1 is also sensitive to single mismatches, but variably so, with Kleinstiver et al. reporting...reporting that Cpf1 can tolerate mismatches at gRNA positions 1, 8, 9, and 19-23. Accordingly, the 3’ end...PubMed PMID: 26411297 Resources on the Addgene Blog Catch Up On Your Cpf1 Background Read About CRISPR Competitor...
  7. Controlling for Off-target Effects with a New Genome-wide CRISPR Screen Design

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    Blog Post
    ...exact or 1-bp mismatch off-targets had greater toxicity than guides that had zero mismatch off-targets....off-target activity: 1) mismatches closer to the PAM are less tolerated than mismatches more distal to the ...off-targets. Guides with 2-bp mismatch off-targets were only toxic if they had 5+ off-target sites. Results from...comparing the toxicity of guides that have 1-bp mismatch off-target sites, short guides had reduced toxicity...currently available from Addgene Other Resources Watch Dr. Michael Bassik’s lecture on “Multiplexing with...
  8. Antibodies 101: Conventional vs Spectral Flow Cytometry

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    Blog Post
    ...antibodies are from the same batch, to avoid unmixing issues from batch-to-batch variation. Tandem dyes (two...conjugated together) can be especially sensitive to batch effect. For example, when a PE molecule is conjugated... Cy7 molecules are added during that particular batch. This can present particular difficulty in unmixing...sample is stained with a PE/Cy7 antibody from a batch that is not the same as your single color control...
  9. Cpf1: A New Tool for CRISPR Genome Editing

    Type
    Blog Post
    ...with single and double mismatches throughout the 23-base sequence. Double mismatches ablated Cpf1 activity...pair gRNA-target mismatches on modification by AsCpf1 (red) or LbCpf1 (blue). Mismatch positions are indicated...bases 19-23). Cpf1 is also sensitive to single mismatches, but variably so, with Kleinstiver et al. reporting...reporting that Cpf1 can tolerate mismatches at gRNA positions 1, 8, 9, and 19-23. Accordingly, the 3’ end...
  10. CRISPR 101: Off-Target Effects

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    Blog Post
    ...“Off-target effects” a vague catch-all term for unintended consequences in an experiment. For CRISPR ...to select a Cas enzyme with low tolerance for mismatches within the gRNA sequence. Graphic courtesy... or mutated to be more specific for exact gRNA matches (Rabinowitz and Offen). Of note, most of these ...these optimized Cas enzymes prevent cutting at mismatched guide sites, but not necessarily binding to these... activity at those sites, especially when DNA mismatches are involved. Two other approaches have been ...non-targeting’ gRNA, a gRNA which doesn’t perfectly match any site in the genome. While this may effectively...
  11. Identifying Sequence Elements with SnapGene's Feature Database

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    Blog Post
    ...devising rules for identifying a feature even when the match is imperfect. SnapGene's feature database The source...detection algorithm that tolerates occasional mismatches or indels. Empirical tests indicated that a reasonable...to allow searches for a perfect protein sequence match even when the DNA sequence has changed. Identifying...database. Another limitation is that by tolerating mismatches, our algorithm could annotate a feature inaccurately... strain to newly sequenced strains through our mismatch tolerant detection algorithm and thereby speed...
  12. Antibody Guide

    Type
    Collection
    ...small aliquots of many different antibodies and do batch validation up front rather than risk delaying a ...
  13. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

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    Blog Post
    ...to the presence of mismatches within the DNA and the positions of these mismatches. To detect SARS-CoV...catalytically active in the presence of two or more mismatches in the cRNA:target duplex and will not give a...dCas9 complexes containing sgRNA that have no mismatches bind to the immobilised target sequences. Upon...making it an affinity-based method. Due to the mismatch sensitivity of FnCas9, this is also a good way...
  14. Tips for a 1st Time CRISPR User (by a 1st Time CRISPR User)

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    Blog Post
    ...cleaves double stranded DNA (dsDNA) at basepair mismatches. To use this tool to detect a BRAF gene edit,... control cells, which should contain basepair mismatches at the site of the edit. Using Surveyor nuclease...nuclease followed by gel electrophoresis, these mismatches are indicated by the presence of DNA cleavage ...isn’t in the middle of the PCR product. If the mismatch is in the middle of the PCR product, you would...cells. Surveyor nuclease was used to digest (+) mismatches in DNA duplexes (513 bp), as indicated by the...
  15. Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering

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    Blog Post
    ...methyl -directed mismatch repair (MMR) system. MMR’s job is to correct DNA mismatches that occur during...activation.  The first way is to introduce a C/C mismatch at or within 6 base pairs of the edit site. This...when activation of MMR is avoided Introduce C/C mismatches or silent changes in wobble codons to avoid MMR...Enhanced levels of λ Red-mediated recombinants in mismatch repair mutants. Proceedings of the National Academy...
  16. SpyLigase Irreversibly Locks Peptides Together for Efficient Cell Capture

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    Blog Post
    ..., just 13 amino acids, but SpyCatcher is a protein. You can fuse SpyCatcher onto things, but even better...particular. They recently introduced the SpyTag/SpyCatcher system, based on a protein isolated from Streptococcus...It came from our work in developing the SpyTag/SpyCatcher system, to be able to grab on to proteins irreversibly...
  17. Plasmids 101: How to Verify Your Plasmid Using a Restriction Digest Analysis

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    Blog Post
    ...construct, and verify that the plasmid you received matches the expected sequence. Here at Addgene, we use ... 3) produces bands at 6kb and 1.2kb (red box), matching the backbone and insert, respectively. The results...results on the gel correspond to the predicted sizes. Watch this video for a quick overview of how to analyze...the optimal working conditions for each enzyme. Watch out for methylation issues. Enzymes like XbaI and...
  18. Plasmids 101: Methylation and Restriction Enzymes

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    Blog Post
    ...role in regulating genome replication, repairing mismatched basepairs or small indels that occur during DNA... methylase adds a methyl group to the adenine of GATC stretches of DNA Dcm methylase adds a methyl group...and will therefore have methylated adenines in any GATC sequences found in the plasmid. When the PCR products...mutation (as these would also be deficient in mis-match repair functions of Dam), so these strains should...
  19. Career Coaching for Scientists: Why and Where Do I Find One?

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    Blog Post
    ...out there, so finding a good one that is a style match for your needs can take some research.  It helps...coaches and I can't tell you which one will be a match for your needs, but here are a number I have come...group is that sometimes this offers the option of matching with the best person in the group for your needs... PhD is in History, I think she would be a good match as a coach for many scientists.  Sometimes it can...
  20. Synthetic promoter AAVs for cell-type specific expression in retinal cells

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    Blog Post
    ..., the Roska lab built synthetic promoters from scratch and tested to see if they drove cell type specific...channelrhodopsin, fused to a fluorescent GFP marker (CatCH-GFP). The lab deposited AAV plasmids containing ...Synthetic promoters did, however, tend to loosely match the specificity of their source genes, i.e. if a...drive expression of a Cre-dependent fluorescent CatCH-GFP reporter. Expression of GFP will only result...
Showing: 41 - 60 of 340 results