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  1. Antibodies 101: Immunoprecipitation

    Type
    Blog Post
    Published
    Dec. 7, 2021, 2:15 p.m.
    ...this versatile technique.  Immunoprecipitation Overview An immunoprecipitation reaction is typically carried...Immunoprecipitation (IP) uses immobilized antibodies, or immunoglobulins, to isolate a specific protein...primary antibody Immobilization is the key to immunoprecipitation and simply refers to the process of anchoring...
  2. Addgene Depositors Get More Citations

    Type
    Blog Post
    Published
    April 20, 2017, 2:30 p.m.
    ...Addgene plasmids get more citations So what do we find? Lots more citations for the papers with plasmids... difference in citations after controlling for journal. And so, while our quantitative analysis cannot...editing paper on CRISPR/Cas amassed nearly 2,400 citations in its first four years (1). In addition to publishing...associated with Addgene deposits accumulate more citations than those without Addgene deposits? Even more...network of articles to track the total number of citations the paper receives. From the database we pulled...papers published in other years also get many more citations This isn’t the whole story, though. It would ... great to know how much of that difference in citations is caused by depositing a plasmid with Addgene...
  3. Droplet Digital PCR for AAV Quantitation

    Type
    Blog Post
    Published
    Jan. 16, 2020, 2:18 p.m.
    ...producing AAV vector preparations, we have used quantitative PCR to evaluate the physical titer of our preps...digital PCR (ddPCR) comes in. AAV titering using quantitative PCR Before we dive into the details of ddPCR...ddPCR, we should first note that quantitative PCR (qPCR) has been a powerful tool for quantifying AAV for...
  4. Deep Dive: Statistical Tests (Comparisons)

    Type
    Blog Post
    Published
    March 7, 2023, 2:15 p.m.
    ... you. Statistics – The basics Statistical analysis is what determines if there is statistical significance... several core factors of statistics relevant for many downstream statistical tests.   Independent variables...are statistically different. They are classic parametric tests and one of the simplest statistical tests...described above. Violated assumptions and statistics Statistical power, the ability to correctly identify... non-parametric statistical tests! Adding it all up  There are many, many statistical tests beyond the...your friendly neighborhood biostatistician happy by making your statistical analysis plan when you design...Wissing, Dennis R., and Timm, Donna. Statistics for the nonstatistician: Part I. South Med J., 105(3): 126...
  5. The Golden Stopwatch Award: Recognizing Facilitators of Research

    Type
    Blog Post
    Published
    Sept. 5, 2019, 1:06 p.m.
    ...the plasmid here yet? A quick look at your order status on addgene.org identifies the hold-up. Your Material...possible new awardees, and we’re happy to share stats and strategies with tech transfer offices. Drop ...Sloan-Kettering Cancer Center  Monash University  Montana State University  National Institute of Diabetes & Digestive...
  6. Capturing a Moment with Marc Zimmer’s “The State of Science”

    Type
    Blog Post
    Published
    July 30, 2020, 1:15 p.m.
    ... Marc Zimmer’s recent book, The State of Science: What the Future Holds and the Scientists Making It ... ago. Teaching by example No examination of the state of science would be complete without the inclusion... last decade. He describes the detection of gravitational waves--a story I was much less familiar with...to. The problems and challenges described in The State of Science have not changed in “COVID times,” but...next week.   A stepping stone When I discussed The State of Science with the five Addgene colleagues who ... learn everything about one specific topic, The State of Science could be a jumping off point to explore...
  7. DIY DNA Ladders from Penn State University

    Type
    Blog Post
    Published
    July 14, 2017, 2:30 p.m.
    ... Commercial DNA Ladder Penn State Ladder: Homemade Plasmid Prep Penn State Ladder: Commercial Plasmid ...undergraduate students led by Dr. Song Tan at Penn State developed the plasmids, pPSU1 and pPSU2. When restriction...$200-$500 for 1000 lanes worth of ladder. The Penn State ladders are significantly cheaper. When using a ...
  8. Deep Mutational Scanning with One Pot Saturation Mutagenesis

    Type
    Blog Post
    Published
    Feb. 22, 2017, 3:30 p.m.
    ...ready for deep mutational scanning.     3 reasons to be interested in deep mutational scanning Hundreds...effect of multiple mutations in combination and possibly discover unexpected epistatic changes in protein...combination of library coverage, mutational efficiency, control over where mutations are introduced, and scalability...still work if the orientation of the BbvCI site(s) of the gene are in the same orientation as those in the...Scientists use deep mutational scanning to simultaneously test how multiple amino acid changes affect...link genotype to phenotype that can be used with mutational scanning: ligand binding assays, phage display...mutagenesis Several methods can be used to create mutational scanning libraries. While each of these methods...
  9. A new platform for fast functional characterization of potentially cancerous mutations

    Type
    Blog Post
    Published
    May 7, 2019, 12:39 p.m.
    ...Collection for “Functional Annotation of Somatic Mutations in Cancer.” Of all the mutations and fusions represented...attempting to characterize mutations in a pooled cell population, as mutations with strong phenotypic effects...types of mutations they identified included gene amplifications and fusions, missense mutations, and indels...assay allows first-time functional annotation of thousands of mutations The researchers used the collection...Kwok-Shing, et al. "Systematic functional annotation of somatic mutations in cancer." Cancer Cell 33.3 (2018)...Thousands of mutations have been implicated in cancer. Yet, the majority of them remain uncharacterized...moderate throughput functional genomic platform to annotate genetic perturbations that may play significant...
  10. Increasing Your Work's Visibility with Addgene: Citation, Search, and Collections

    Type
    Blog Post
    Published
    March 10, 2016, 3:30 p.m.
    ...your research interests. We do this by promoting citation, supporting sophisticated search, and curating...reference for its original publication. To help facilitate this process, we explain how to cite plasmids...Addgene right on our plasmid pages and provide a citation that you can put straight into your reference ...visibility of both you and the original depositor. Our citations feature makes it so that, when you cite a plasmid...quick note -  While it is tempting to rely on the citation number when comparing two plasmids, we recommend...Impact Are Evolving Check out the Blog Post on Our Citations Feature Browse More Inside Addgene Posts Additional... citation...
  11. Recombinase-based State Machines Enable Order-dependent Logic in vivo

    Type
    Blog Post
    Published
    July 28, 2016, 2:30 p.m.
    ...Recombinase-based state machines (RSMs), which take on a particular DNA-sequence configuration (state) based on...effects on the state cannot be undone and also limit the set of possible downstream states that can be achieved...order of inputs results in only one final state, then the state of the RSM will tell you precisely what ...might one read the state of an RSM? The most straightforward way to read the state of an RSM is to sequence...is to interrogate state with qPCR. The re-arrangement of DNA segments in each state of a register enables...certain states of interest. For example, in Figure 2 below we present a two-input, five-state GRSM register...green fluorescent proteins in each state. The three methods of state interrogation mentioned above (Sanger...
  12. Don’t FRET: Bimolecular Fluorescence Complementation Makes Visualizing Protein-Protein Interactions Easy

    Type
    Blog Post
    Published
    Aug. 27, 2020, 1:15 p.m.
    ...Bimolecular Fluorescence Complementation (BiFC). What is bimolecular fluorescence complementation? Bimolecular fluorescence... TK (2006) Design and implementation of bimolecular fluorescence complementation (BiFC) assays for the... fluorescence complementation is a method for detecting protein-protein interactions that uses split fluorescent...  Applications for bimolecular fluorescence complementation BiFC has been used to directly visualize PPIs...success of BiFC experiments. The ideal control is a mutated variant of one or both of your PIPs in which the...Living Cells Using Bimolecular Fluorescence Complementation. Molecular Cell 9:789–798. https://doi.org/...Kerppola TK (2013) Bimolecular Fluorescence Complementation (BiFC) Analysis of Protein Interactions in ...
  13. Your Lentiviral Plasmid FAQs Answered

    Type
    Blog Post
    Published
    April 23, 2014, 1:08 p.m.
    ...wildtype 5'LTR, which requires the presence of the Tat protein to work, while 3rd-generation transfer plasmids...chimeric 5'LTR removes the requirement for the HIV Tat protein, thus decreasing the probability of creating...plasmid encoding HIV proteins gag, pol, rev, and tat. 3rd generation systems require an envelope plasmid...transfer plasmid to eliminate the need for the HIV Tat protein and consequently are considered safer. Second-generation...system because the wildtype 5'LTR promoter requires Tat to function. Third-generation plasmids can be packaged...Second-generation contains those three genes plus tat. The envelope plasmid provides a heterologous envelope...biosafety available for the technology. The minor limitation in using the 3rd-generation system is that it...
  14. Lentiviral Vector Uses and Overview

    Type
    Blog Post
    Published
    May 19, 2016, 2:30 p.m.
    ...virus. Second, Tat is eliminated through the addition of a chimeric 5’ LTR containing a Tat-independent ...polymerase), Tat (viral transactivator for transcriptional activation from the 5’ LTR) and Rev (facilitates nuclear...transfer plasmids. The packaging plasmid carried a mutated HIV-1 provirus that couldn’t package itself due...envelope plasmid contained a viral envelope to dictate the tropism, or types of cells the vector could...flanked by HIV-1 long terminal repeats (LTRs) that facilitate viral packaging and host genome integration. ...
  15. Quick Guide to All Things Lentivirus

    Type
    Blog Post
    Published
    March 21, 2017, 2:30 p.m.
    ...for the production of a viral particle (Gag, Pol, Tat, Rev and Env) and the transfer plasmid encoding the... a clinical setting. In this generation, the HIV Tat gene (previously used to drive expression from the... has been inserted in this LTR so you don’t need Tat to transcribe the viral genome in producing cells...the LTRs) has been removed, Rev (which facilitates nuclear export) is expressed from a separate plasmid...active area of research due to the possibility that mutation or recombination with human retroviruses could... In this case, your gene is repressed in steady state and is expressed when Dox is added to the culture...centrifuge the culture supernatant in order to precipitate the viral particles. Some protocols suggest adding...
  16. Another Pathway into Cells: iTOP

    Type
    Blog Post
    Published
    June 23, 2015, 8:37 p.m.
    .... One such CPP was discovered in the HIV protein Tat. Although CPP fusions can translocate a cell membrane...toxin, indicating a 70% frequency of biallelic mutations. Importantly, hESCs retained their stemness, indicating... remove the risk of viral integration causing mutations and gene expression changes elsewhere in the genome..., working directly with proteins removes the limitations of packaging size associated with viral vectors...
  17. Overcoming the Challenges of Lentiviral Production

    Type
    Blog Post
    Published
    Aug. 7, 2018, 12:31 p.m.
    ...longer requires the viral transactivator, Tat. For more information on the different generations of lentiviral...promoter of the 5’ long terminal repeat (LTR) is mutated in third generation systems such that it no longer...spin columns, and polyethylene glycol (PEG) precipitation. All of these methods ultimately isolate the...downstream applications. For example, while the PEG precipitation method is relatively inexpensive and does not...not require an ultracentrifuge, PEG will precipitate all proteins in a solution, not just the lentivirus...
  18. Hot Plasmids February 2024

    Type
    Blog Post
    Published
    Feb. 20, 2024, 2:45 p.m.
    ...Figure 1: A) Cell-penetrating Cas9, fused to HIV TAT, Myc and SV40 Nuclear Localization Signals, and GFP...co-incubate it with an “assist peptide” that facilitates endosomal escape. Combining Cas9-PAGE with lentiviral...Balasubramanian and colleagues showed the single mutation E138D is sufficient to disrupt dimerization while...
  19. Four Base Editing Reporters to Monitor and Enrich Editing in Real-time

    Type
    Blog Post
    Published
    July 7, 2020, 1:15 p.m.
    ...by a ‘CAC’ codon that is converted to a ‘TAC’ or ‘TAT’ after a C-to-T base editing event. This edit changes...Base editors create specific point mutations in the genome, but they’re inefficient compared to CRISPR... is a bicistronic construct that consists of a mutated mCherry and a downstream constitutively active ...the eGFP reporters the Harris lab individually mutated three codons in eGFP to eliminate fluorescence....eGFP reporters rely on the correction of point mutations in eGFP that results in the restoration of fluorescence...GFP construct, that contains an ACG start codon mutation, and integrated it into human and mouse cells ...events in vivo. As GO relies on the correction of a mutated start codon to initiate protein expression, it ...
  20. Viral Vectors 101: Integrase-Deficient Lentiviral Vectors

    Type
    Blog Post
    Published
    May 13, 2025, 1:15 p.m.
    ...The packaging plasmid contains Gag, Pol, Rev, and Tat genes. Specifically for our knowledge here, the Pol...by long terminal repeat (LTR) sequences, which facilitate integration of this portion into the host genome...vesicular stomatitis virus G protein (VSV-G), which facilitates viral entry into the host cell.  Transfecting...(see Figure 2).  Figure 2: Schematic representation of integration process and episomal forms of...Addgene: psPAX2-D64V. This construct has the D64V mutation, a single amino acid change (from aspartic acid...detecting vector particle components or performing quantitative PCR titration of vector DNA in samples harvested...Insertional mutagenesis combined with acquired somatic mutations causes leukemogenesis following gene therapy of...
  21. 3 Tips to Improve HDR Efficiency for CRISPR Editing in Human Cells

    Type
    Blog Post
    Published
    Sept. 5, 2017, 1:58 p.m.
    ...blocking mutation. Despite the fact that both the blocking mutation and our intended mutation were on ...or heterozygous mutations. 1. Increasing HDR accuracy with CRISPR/Cas-blocking mutations After genome editing...sequence. The idea was that these “blocking mutationsmutations prevent CRISPR from re-cutting the target...blocking mutations? This depends entirely on the locus you are editing, and if the blocking mutation needs...intended mutation while taking advantage of the improved efficiency provided by blocking mutations. Essentially...cut site to mutation distance and editing efficiency.   3. Optimizing "cut-to-mutation distance" for... Alzheimer mutations we study are heterozygous in patients. As the probability of mutation incorporation...
  22. Site Directed Mutagenesis by PCR

    Type
    Blog Post
    Published
    Aug. 2, 2016, 2:30 p.m.
    ...applies to plasmids, but may also facilitate genome editing. Tailored mutations are commonly introduced to endogeneous...brief, point-mutations can be introduced to plasmids using primers (with the desired mutation) in a PCR ...mutagenesis vastly facilitates the subsequent process of screening for succesfully mutated clones. Forward...introduction of specifically designed mutations (not limited to frame shift mutations). Consequently, site directed...restriction sites), in mapping of regulatory elements (to mutate promoters/enhancers in reporter constructs), in...high homology to the endogenous target, yet to facilitate the repair, the template should be resistant ...template, site-directed mutagenesis can be used to mutate the PAM sequence (an NGG sequence critical for ...
  23. Fluorescent Proteins 101: Photoactivatable Fluorescent Proteins

    Type
    Blog Post
    Published
    April 25, 2017, 2:30 p.m.
    ...photoswitched from a dark state to a bright fluorescent state (“kindling”), and from a bright state to a dark non-...be activated from low fluorescent states to high fluorescence states, they can change from one fluorescent...switched on from a state of dim or no fluorescence, to a brighter fluorescent state by exposure to a specific...Padron is photoconverted from a dark state, to an activated state, emitting bright green fluorescence.... and ability to switch from a dark state to a red fluorescent state make them useful for 2-color imaging...from Jellyfish (Aequorea victoria) GFP (wtGFP) by mutating Threonine 203 to Histidine (T203H) (1). wtGFP ...chromophore which contribute to the 2 peaks of wtGFP’s excitation spectrum- a major 397 nm peak and minor 475 nm...
  24. Antibodies 101: Designing Your First Flow Panel

    Type
    Blog Post
    Published
    May 28, 2024, 1:45 p.m.
    ...within atoms to a higher energy state. This process is called excitation. After a short period, the electrons...lower energy state, whereby a photon is emitted. This step is called emission. During excitation, some of ...speak of excitation and emission spectra. Both spectra possess clear maxima where excitation and emission... to the global maximum of PE's excitation spectrum where the excitation efficiency is much greater. As...signal.   Figure 2: Excitation and emission spectra for PE. The excitation spectrum shows two maxima...While APC's global excitation maximum lies around 650 nm, APC-Cy7's global excitation maximum is about ... Figure 3: Excitation and emission spectra for APC and APC-Cy7. While the excitation spectra of both...
  25. Targeted Mutagenesis with EvolvR

    Type
    Blog Post
    Published
    Feb. 21, 2019, 1:15 p.m.
    ...culture, so bacteria must be grown in a turbidostat. Only mutate particular types of nucleotides. Both...rate was 2.5 x 10-6 mutations per nucleotide per generation vs. 10 x 10-10 mutations per nucleotide per...increase the mutation rate and extend the editing window of EvolvR: (1) two additional mutations to PolI3M...many known spectinomycin resistance mutations, several new mutations were identified by targeting EvolvR...to generate specific mutations in your plasmids Use REPLACER Mutagenesis to mutate your plasmid Resources... sequence can help scientists identify and/or facilitate the evolution of new phenotypes, and forward ...bacterial growth conditions in order to maximize the mutation rate. For example the Phage Assisted Continuous...
  26. Screening for Successful Genome Editing with Digital PCR

    Type
    Blog Post
    Published
    March 30, 2017, 2:30 p.m.
    ...Surveyor® or T7E1) for mutation detection. While these methods paved the way for mutation validation, we found...individual target molecules based on their mutation status. The drop-off probe is designed to perfectly...and is not capable of binding a mutated target. The amount of both mutated and wild type target in each ...samples with mono-allelic mutations versus those with the bi-allelic mutations typically desired when screening... comes time to (hopefully) validate successful mutation of your favourite gene, there are several different... to help guide you through the rough waters of mutation validation, such as this "CRISPR 101" post. Next-generation...Since there are many thousands of partitions, statistical modelling can be used to determine the actual...
  27. Choosing the B(right)est Fluorescent Protein: Photostability

    Type
    Blog Post
    Published
    June 8, 2017, 2:30 p.m.
    ...fluorophore primarily depends on the excitation power and the excitation wavelength. A fluorophore is less...absorb the excitation light less efficiently. Similarly, decreasing the power of the excitation light reduces...acquired at low excitation powers. Note, however, that, at a 14-fold higher excitation power, the photostability...lightbulb or exchanging excitation filters). This avoids substantial changes in excitation power and will help...reduces the number of excitation/emission cycles per unit of time, decreasing the likelihood that a fluorophore...story. The photobleaching rate does not depend on excitation power in a linear fashion. This implies that ...Cranfill et al, 2016). This non-linear dependence on excitation power is important since different fluorescence...
  28. Illuminating Choices: A Guide to Selecting Fluorescent Dyes and Ligands

    Type
    Blog Post
    Published
    March 21, 2024, 1:15 p.m.
    ... electrons are elevated from a ground state to an excited state through the absorption of photons. After... elevation in this excited state, the electron returns to its ground state by emitting a photon with slightly...10nm) and overlap of excitation profiles is vital for the accurate interpretation of FRET-based experiments... or the difference in wavelength between peak excitation spectrum and emission spectrum. Fluorescent dyes...chemical structure, leading to differences in their excitation and emission wavelengths, which are pivotal in...dye is fluorescein isothiocyanate (FITC), with excitation/emission peak at 495/517 nm. FITC binds to an...this include coupling to an antibody, whereby excitation of blue light will indicate where FITC is bound...
  29. Plasmids 101: FLEx Vectors

    Type
    Blog Post
    Published
    April 28, 2016, 2:30 p.m.
    ... same orientation, the SSR will excise the DNA fragment. By manipulating the number, orientation, and ...the sense orientation, followed by the mCherry coding sequence in the antisense orientation (Figure 1,...Introduction of a conditional point mutation or functional mutation in vivo: Similar to a conditional rescue...-specific recombination events, and that the orientation of the flanking loxP sites directs the Cre recombinase...recombination. The FLEx switch takes advantage of the orientation specificity of the site-specific recombinases...flanked by target sites (floxed) in opposing orientations, a SSR will invert the DNA sequence between ...wild-type pair (loxP, black arrowheads) and one mutated pair (for example- lox511, white arrowheads). It...
  30. Which Fluorescence Microscopy Techniques is Best for Me?

    Type
    Blog Post
    Published
    Oct. 10, 2017, 1:57 p.m.
    ...metal disk containing a number of holes rotates through the excitation light path. Each hole corresponds to...traditional confocal due to limitations in light penetration mentioned above (5). Thick static samples Ex: Fixed...detector or restricting fluorescence to specific excitation volumes to enhance spatial contrast (i.e. optical...microscopy. Collimated (non-converging or diverging) excitation light exits the microscope objective evenly illuminating... CT scanner. This is accomplished by focusing excitation light to a point in the sample and raster scanning...First, widefield and confocal microscopy project excitation light through the entire axial volume of a sample...signal intensity. 2-Photon microscopes restrict excitation (and bleaching) to a single focal point. This...
  31. REPLACR Mutagenesis: Replacing In Vitro Recombination Methods

    Type
    Blog Post
    Published
    Feb. 10, 2016, 3:30 p.m.
    ...Types of Mutations Insertions, deletions, point mutations Insertions, deletions, point mutations Insertions...inactivating/activating mutations. In biomedical research, modeling patient mutations using SDM can help determine... make a point mutation, you design two oligonucleotide primers with the desired mutation, then use those...Insertions, deletions, point mutations Insertions, deletions, point mutations PCR Reactions 1 1 1 per fragment...commercial kits are available for making small point mutations, large deletions/insertions require complicated...PCR amplify the template plasmid. The parental, nonmutated DNA is digested with methylated DNA-specific ...express phage recombination machinery, which facilitates easy genetic modification by homologous recombination...
  32. Plasmids 101: Common Lab E. coli Strains

    Type
    Blog Post
    Published
    Nov. 7, 2014, 2:56 p.m.
    ...uptake, iron uptake receptor mutation. T1/T5 Phage resistance gal Mutation in galactose metabolism pathway...DNA, preparing unmethylated DNA, and more. Many mutations that make these features possible are present ...present in most commercial strains, especially mutations that make major improvements such as those that increase...found in E. coli strains. Table 1: Common gene mutations found in E.coli strains Gene(s) Description...Functional Consequence dam DNA adenine methylase mutation (GATC) Preparing unmethylated DNA, important when...ex: ClaI or XbaI) dcm DNA cytosine methylase mutation (CCWGG) Preparing unmethylated DNA, important ...enzymes that are methylation sensitive. dnaJ Mutation in a chaperonin gene Increases the stability of...
  33. Fluorescent Proteins 101: Green Fluorescent Protein (GFP)

    Type
    Blog Post
    Published
    May 15, 2014, 3:33 p.m.
    ...wildtype protein and facilitating its widespread use in research. Many other mutations have since been introduced... and their mutations relative to wildtype GFP. Although not listed here, many permutations within each... and the mutation definitions found in Table 2 may not apply. Table 1: The specific mutations comprising...2: Functional role of specific mutations in GFP derivatives Mutation Known Function S65T Increased...little truncation is tolerated, however, point mutations are acceptable. GFP's main advantage over conventional...In 1995, Roger Y. Tsien described an S65T point mutation that increased the fluorescence intensity and ...photostability of GFP. This also shifted its major excitation peak from 395 nm to 488 nm, effectively ameliorating...
  34. Mouse Modeling, Part 2: Breeding and Crossing Mice

    Type
    Blog Post
    Published
    Aug. 6, 2019, 12:55 p.m.
    ...commonly used to introduce multiple mutations. This is because as more mutations are introduced into a single...arise when crossing mice with multiple mutations is if the mutations are on the same chromosome. Homologous...engineering should be used to separately introduce each mutation independently into different mice, and then these...production of offspring that have a combination of the mutations engineered into each of their parents. Here’s ...mice that are each homozygous for one of the two mutations that you want combined in your offspring. Genotyping...producing mice with your desired combination of mutations. Assuming your parental mice were all homozygous... to a mouse that is homozygous for a different mutation, the F1 offspring will be either hemizygous or...
  35. Plasmids 101: Colony PCR

    Type
    Blog Post
    Published
    May 12, 2016, 2:30 p.m.
    ... about the orientation of the insert Orientation-Specific Tells you the orientation of the insert... provide information about the orientation of the insert. Orientation-specific primers: If you need ...information about insert orientation, then you might consider designing orientation-specific primers. Blunt...primers, 2) backbone-specific primers, and 3) orientation-specific primers.       Insert-specific primers...insert is present but not if it’s in the correct orientation or even if it’s in your plasmid backbone. Backbone-specific...an example of when you might want to know the orientation of the insert. One member of this type of primer...or no" test results Doesn't tell you the orientation of your insert or if the insert is in your plasmid...
  36. An “elegans” Approach to Better CRISPR/Cas9 Editing Efficiency

    Type
    Blog Post
    Published
    Dec. 17, 2020, 1:30 p.m.
    ...dominant mutation, known as co-conversion (Arribere et al., 2014). In both cases, the selected mutation must...repair of a lethal mutation should remove much of the unedited “haystack”, facilitating recovery of edited... of lethal mutation co-selection. Only animals rescued for the conditional lethal mutation survive the...determined optimal PAM orientation for editing using two Cas9 targets. An orientation where the 5’ ends of...Cas9 allows us to delete sequences and introduce mutations and epitopes with unprecedented ease. These new... homozygous, outcrossed knock-in ready for experimentation. In 2014, several manuscripts published in ...approach relying on repair of a conditional-lethal mutation to identify edits with minimal screening effort...
  37. Treating Muscular Dystrophy with CRISPR Gene Editing

    Type
    Blog Post
    Published
    Jan. 26, 2016, 3:30 p.m.
    ...models with mutations in human-relevant exons 45-55, rather than in the traditional exon 23-mutated mouse model... genetic diseases, the mutational landscape is broad and varied, necessitating the development of many...modification, to repair or add in disease-causing mutations, but, until recently it hadn’t been used to treat... males. DMD is caused primarily by frameshift mutations in dystrophin, a protein essential for proper ...sequence appears to be nonessential. Within the mutational hotspot for dystrophin, exons 45-55, there are...partially functional protein. Individuals with these mutations are often asymptomatic, or have only mild symptoms... oligonucleotide exon skipping (OEN) to remove mutated exons from the dystrophin transcript. Unfortunately...
  38. CrispyCrunch: High-throughput Design and Analysis of CRISPR+HDR Experiments

    Type
    Blog Post
    Published
    Feb. 7, 2019, 2:16 p.m.
    ...Optimal mutation in-depth One the most sophisticated features of CrispyCrunch is how it mutates guide sequences...region, the mutation may cause side-effects. Further, work by John Doench et al. shows that mutating a single... After each mutation, it will check the CFD score. If it is below 0.03, it stops mutating. (Note: the ... example, it ranks guides by CFD score, and it mutates HDR donor templates to avoid re-cutting when needed...for TagIn. HDR requires the additional step of mutating guide sequences in a way that prevents re-cutting...do it best. Scientists are typically advised to mutate the PAM to which the guide binds. However, if the...implemented the following algorithm for optimal mutation in CrispyCrunch: If the guide PAM resides outside...
  39. Using CRISPR/Cas9 to Edit Disease Out of the Genome

    Type
    Blog Post
    Published
    June 23, 2022, 1:15 p.m.
    ...developing anti-CRISPR proteins aid the limitation of these mutations, to control the CRISPR system activity...could be used to edit several autosomal-dominant mutations that have been connected to the early onset of... CRISPR/Cas9 corrects Alzheimer’s disease mutation in basal forebrain cholinergic neurons derived...Academy of Sciences found that mice with a dominant mutation in a gene that causes cataracts could be rescued...demonstration of use of genome editing to correct point mutations in two diseases with real phenotypic effect.” ...noted that CRISPR/Cas9 has been used to generate mutations in a wide range of organisms, but its potential...phase of crisis where they 'collect' a number of mutations.” Cystic fibrosis may not be the most likely candidate...
  40. Data Freedom: The Expansion of Data Sharing in Research Publications

    Type
    Blog Post
    Published
    Aug. 5, 2014, 6:51 p.m.
    ...inappropriate statistical methods, omission of some data, etc.  The firestorm that followed implementation of the...condensed into a statistically evaluated set of values.  However, to evaluate the interpretation of the experiment...Instead, selected images are said to be representative or the statistical variation is calculated and placed...overnight revelation, rather it was the result of consultations between researchers and publishers. Nonetheless.... The PLOS policy on data access is a formal statement that is already practiced or required by many ...means that supporting datasets must be logically annotated and arranged, as in an actual publication and ...efficient science. Improvements in our discipline for annotation and archiving of data are likely to improve research...
  41. Fluorescent Proteins 101: When GFP lets you down

    Type
    Blog Post
    Published
    Aug. 23, 2018, 12:05 p.m.
    ...number of limitations that you may run into if you choose to use it. Several of these limitations and possible...protonated and a deprotonated state (Tsien, 1998). The deprotonated state has an absorbance maximum around...protonated state, however, does not absorb light at 488 nm. The ratio between the two states is reflected...encoded probe, but there are limitations. Being aware of the limitations is important for the successful...mEGFP. This variant was made by introducing two mutations (F64L, S65T) in the original jellyfish GFP (AvGFP...with improved brightness (Tsien, 1998). Another mutation (A206K) is necessary to generate the strictly ...autofluorescence is less of a problem when the excitation wavelength is shifted to longer wavelengths. ...
  42. Harnessing Bacterial Toxins for Allelic Exchange

    Type
    Blog Post
    Published
    Aug. 15, 2019, 12:30 p.m.
    ...astounding number of ways to create chromosomal mutations in bacteria, so many that it may be difficult ...path to take. A quick and easy way to introduce a mutation in the chromosome is to disrupt expression of ...genes. However, there are ways to create scarless mutations, ones that don’t leave any undesired scars in ...technology has also aided in the creation of scarless mutations, both in stand-alone systems (Jiang et al., 2013...plasmid curing steps, and can generate off-target mutations. Modifying bacterial genomes using counter-selectable...is frequently called allelic exchange. Here, a mutated allele introduced from a conjugative plasmid replaces...versatile technique, and is less prone to off-target mutations. Ultimately, successful allelic exchange requires...
  43. Donations from Addgene to Yield Answers for Rare Disease Researchers

    Type
    Blog Post
    Published
    Sept. 15, 2015, 2:30 p.m.
    ...understand Lowe Syndrome, a devastating genetic disease caused by mutations in the OCRL1 gene that leads...different mutations in a gene called SOX10. To understand the functional role of those mutations, they now...to work to explore the effect of various OCRL1 mutations on cell behavior in greater detail. The goal is...sensitive to sunlight and prone to developing metastatic melanomas and other cancers. Joshua Wang (bottom...CRISPR-Cas9 constructs from Addgene to gene-edit mutations into XP genes and other genes involved in photosensitivity...plasmids to explore the functional differences among mutations responsible for the disease known as Alternating...the brain. McSweeney says they now think that mutations in the gene may prevent neurons from returning...
  44. How to Write a Scientific Review Article

    Type
    Blog Post
    Published
    Feb. 16, 2017, 3:30 p.m.
    ... mentioned, I also added citations in real time as I wrote, so each statement was referenced even in the...studies that reported mutations in that protein (including how frequently a mutation was found and the size...review Once you start reading, there will be a temptation to include every piece of information that was...review articles Whether submitting a review by invitation or by your own accord,  once you have these rules... write, meaning I use the software to add the citations in real time as I write. Things are going to get...from the beginning. I also recommend using the citation style of (Last name, Year) in the document while...experiments. Later, you can easily convert the citation style to whatever the journal requires. Using ...
  45. Rett Syndrome: A History of Research and Therapeutic Outlooks

    Type
    Blog Post
    Published
    Nov. 19, 2020, 2:15 p.m.
    ...Syndrome research. With a shared passion for facilitating research and discovery, Addgene and RSRT have...approaches. What is Rett Syndrome? Caused by a mutation in the methyl-CpG binding protein 2 (MECP2) gene...Zoghbi's lab discovered the first disease-causing mutations in the MECP2 gene leading to Rett Syndrome (Amir... regulate transcription (Baker et al., 2013). Mutations that affect this interaction to varying degrees...determine the clinical severity of different MECP2 mutations. More recently, the Bird lab found that only a... human MECP2 locus and MECP2 protein, showing mutations corrected by CRISPR/Cas9 in wild-type human iPSCs... exciting and promising results for repairing mutations in models of neurological disease. Klaus Rajewsky...
  46. Pushing the Limits of DNA Assembly

    Type
    Blog Post
    Published
    Sept. 6, 2017, 1:01 p.m.
    ...primers with your desired mutation, performing PCR to generate the mutation and linearizing your vector... limit to where the mutation can be placed. With other techniques, when mutations are spaced farther apart...multiple synthetic fragments, create multiple mutations in one or multiple fragments, and generate constructs... Generation of constructs with multiple point mutations Cloning sgRNAs Production of Yeast Expression ...Cassettes Generating constructs with multiple point mutations NEBuilder HiFi can simplify multi-position site-directed...assembling multiple fragments containing the desired mutations. This same process can be used simultaneously ...simultaneously for the generation of one or more mutations – it is as easy as obtaining a plasmid with the gene of ...
  47. Deep Dive: qPCR

    Type
    Blog Post
    Published
    Sept. 29, 2022, 1:15 p.m.
    ... differences of twofold or greater with good statistical significance (Taylor, 2017). With the right conditions...different efficacies DART-PCR No Raw Data Statistically defined log-linear phase   Table 2: ... them back before reporting the data!   Statistical analysis  Getting your RQ value isn’t the end...your analysis process. You’ll still need to do statistical analysis to determine if there are any significant... Yuan, 2006 has a good overview of different statistical analysis methods that pair well with slightly...step, remember we here at Addgene frown upon statistical laxness in all its forms. Reporting your data...provide you with the highest form of flattery - imitation! Use the MIQE guidelines (Bustin, 2009) to ensure...
  48. March for Science

    Type
    Blog Post
    Published
    April 21, 2017, 2:30 p.m.
    ...select your state. State Legislatures: To find the website to contact representatives at the state level you...based on our most accurate interpretation of the world, and this interpretation should not effected by claims...contact your representatives in case you would like to talk with them about science: Representatives: To find...contact information for your representative in the House of Representatives all you need to know is your...march in Washington, D.C., the seat of the United States government? Politics and science are intrinsically... you can click on your state in this map. Finally, the march is meant to inspire scientists to be more...Center: The Politics of Climate Change in the United States CNBC: Kellyanne Conway: “I”m not in the job of ...
  49. CRISPR 101: Making a Knock-In Cell Line

    Type
    Blog Post
    Published
    Dec. 22, 2022, 2:15 p.m.
    ...frameshift mutation. The majority of cellular repair events will generate these types of mutations, making...recognition sequence is destroyed via mutation. By introducing a mutation in either the PAM or the guide recognition...mishaps in this class of genome edit. Knock-in mutations and gene editing Targeted genome editing events... this is not the case for knock-ins. Knock-in mutations typically require an exact DNA sequence to be ...cells. It is important to know that HR is often mutated in cancer cells, specifically in breast and ovarian...recommended you check your cell lines for HR-related mutations before attempting knock-ins by HDR.   ... with some success (Yu et al., Nat Chem Biol). Mutate the PAM or sgRNA sequences Cas9 likely goes through...
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