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Showing: 21 - 40 of 705 results
  1. 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...
  2. 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...
  3. 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 ...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. 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...
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
Showing: 21 - 40 of 705 results