We narrowed to 988 results for: Ran
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TypeBlog Post...systems efficiently transfer a range of protein sizes in minutes without any transfer buffer. These systems...proteins are: (1) separated by size, (2) transferred to a membrane, and (3) detected using antibodies. ...mixture of protein is separated in a gel, transferred to a membrane, stained with antibodies, and finally ...a broad size range to be separated on a single gel. Immobilizing proteins on a membrane Once separated...migrate out of the gel and attach to the membrane. In a wet transfer system the sandwich is completely submerged...filled with a transfer buffer formulated to conduct the electric current. The wet transfer process is very... very effective in transferring a broad range of protein sizes but takes hours to overnight. In contrast...
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Plasmids 101: Terminators and PolyA signals
TypeBlog Post...initiation step of gene transcription; today we'll provide an overview on how transcription stops, or termination...from the transcription machinery. Terminators are found downstream of the gene to be transcribed, and typically...generally serves to promote transcript longevity in eukaryotes and promote transcript degradation in prokaryotes...thought to destabilize the transcription complex, initiating cleavage of the transcript. Figure 1: ...Hepatitis Virus Posttranscriptional Regulatory Element Enhances Expression of Transgenes Delivered by ...terminators in the context of AAV transgene expression levels. Transcription Termination Rho-dependent termination...both prokaryotic and eukaryotic systems must be transcribed into RNA, which occurs in three phases: initiation... -
Minigenomes - a Safe Way to Study Dangerous Viruses Like the Ebola Virus
TypeBlog Post...gene transcription (6). The EBOV genome contains seven viral genes, each flanked by a transcription start...replicated and transcribed in the cell when the appropriate viral proteins are provided in trans (see Other...genes and the minigenome are transcribed (and the viral mRNAs are translated) by cellular machinery. NP ...altering the amount transfected (see Technical Tips). Minigenome replication and transcription In order to replicate...it will terminate transcription and polyadenylate the mRNA. These mRNAs are translated by cellular host... lines that are highly transfectable. The amounts of each plasmid transfected into cells are also extremely...interested in genome replication and transcription of negative strand RNA viruses. References 1. Buchholz... -
Technique: Probe Phage Genomes for Host Binding Proteins
TypeBlog Post...plates. Step 2: Express random phage DNA fragments in E. coli Now that random DNA fragments have been ...nitrocellulose membranes and exposed to IPTG in order to induce protein expression. Cells on the membranes will ...orientation of each membrane on its plate before moving on. Then peel each membrane off the plate (saving...high salt. To probe membranes with target bacterial cells, wash your membranes with PBST to remove salt... on the membrane to bind their target cells, pulling them out of solution. Wash your membranes well with...searches return no candidates. Our strategy: Express random fragments of the phage genome and probe with live...identified using this method. Step 1: Prepare a random fragment library of phage DNA This first step involves... -
Prime Editing: Adding Precision and Flexibility to CRISPR Editing
TypeBlog Post... non-edited strand, they can cause the cell to remake that strand using the edited strand as the template...the nicked target strand. The initial result is a heteroduplex, with overlapping strands of edited and unedited...Improving reverse transcriptase efficiency Building upon prior reverse transcriptase research, the Liu...the edit into one strand, there’s a mismatch between the original sequence on one strand and the edited ... the unedited strand away from the initial nick site (to avoid creating a double strand break), increasing...binds the edited strand, as in the PE3b system, guides nicking of the unedited strand only after editing...process and promote copying of the edited strand to the unedited strand (Chen et al., 2021). The team applied... -
Plasmids 101: Mammalian Vectors
TypeBlog Post... does not guarantee 100% transfection efficiency. Stable transfection A stable transfection is used to...process called transfection. Transfection is somewhat comparable to bacterial transformation (the introduction...the transfected plasmid to be expressed transiently. Since the DNA introduced in the transfection process...the genome to form a stable transfection. Unlike bacterial transformation, scientsts do not "select" for...fluorophore in a later post, so stay tuned! Transient transfection and the elusive "mammalian ORI" For many...plasmid depleted, but still want to use transient transfection methods. Since there are no "natural" mammalian...must be compatible with the cell type they are tranfected into – a bacterial origin of replication (ORI... -
Your Lentiviral Plasmid FAQs Answered
TypeBlog Post...considered. Q2: Can I use lentiviral transfer vectors for transient transfections? A2: Technically, yes. Will ...produced by co-transfecting three essential ingredients: the lentiviral packaging vector, a transfer vector including...specifically for transient expression (find some useful backbones here) or from viral transduction. While not...3rd-generation transfer vectors apart? A3: Addgene defines 2nd- or 3rd-generation transfer vectors based... Are transfer plasmids replication competent? What is SIN? A6: Most (if not all) Addgene transfer plasmids...enhancers and the transgene; such interactions can alter expression of not only the transgene but also that...which is rarely more than 30% of the transfer plasmid. Many transfer vectors are SIN. Packaging plasmid... -
Antibodies 101: Stripping and Reprobing Western Blots
TypeBlog Post... your gel and membrane transfer as normal. Immediately after transfer, dry the membrane to maximize protein...you from having to run a whole new gel and membrane transfer. Let’s get started! Before you begin In the...manufacturer’s instructions for the membrane you are using. Dry nitrocellulose membranes are brittle, so proceed ... as normal! Stripping your membrane Alright, so you’ve dried your membrane and returned it to buffer, ...’ll want to: Rinse the membrane in water or fresh buffer. Cover the membrane in stripping solution and...a fume hood. Rinse the membrane in water or fresh buffer. Cover the membrane in stripping solution and...you need to start a whole new blot? Never fear: membrane stripping is here! Rather than start over, you... -
Viral Vectors 101: Gamma-Retroviral Packaging Systems
TypeBlog Post...γ-Retroviral transfer plasmid encoding a transgene, sgRNA, or shRNA of interest: The transgene sequence is...packaging and transduction are not encoded by the transfer plasmid, but instead are provided in trans by other...integrated into the host genome upon viral transduction. Most transfer plasmids available from Addgene were ...packaging, and transfer) are supplied by three types of plasmids, which are cotransfected into the 293T...cell line. γ-Retroviruses can transduce target cells, but the transduced target cell does not produce ...protein containing Reverse Transcriptase and Integrase components. Transfer cPPT Central polypurine...proviral DNA synthesis. Increases transduction efficiency and transgene expression. Psi (Ψ) RNA target... -
Important Considerations When Using AAVs
TypeBlog Post...their efficiency at transducing different brain regions. Although AAV2 can transduce many tissue types,...Axonal Transport It has been demonstrated that certain serotypes can undergo axoplasmic transport. These...of neurons (retrograde transport) or towards the synapse (anterograde transport), which is a possible ...retrograde and anterograde transport, but they also have similar transport characteristics (velocities...strong CNS tropism (4). If axonal transport is not desirable, transport can be reduced by injecting a smaller...scAAV) (7). As single stranded DNA viruses, AAVs normally require second strand synthesis before gene ...Simon Rumpel. "Analysis of transduction efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5... -
Deep Mutational Scanning with One Pot Saturation Mutagenesis
TypeBlog Post... by the bottom strand versus nicking the bottom strand first followed by the top strand. Both produced...complementary mutant strand (step 2 and 3). Then the uracil-labeled template strand is degraded by uracil...present on both strands of the plasmid. The ssDNA template is generated by transforming a backbone phagemid...ExoI then fully degrades the nicked strand. Synthesize mutant strand: A mix of degenerate primers and the...synthesized DNA strand. Each degenerate primer set contains three consecutive randomized bases (NNN) at...Degrade wild-type template strand: Next, the opposite wild-type DNA strand is nicked by the BbvCI variant...step 1. Then this strand is degraded with ExoIII and ExoI. Synthesize 2nd mutant strand: The second mutant... -
Plasmids 101: Repressible Promoters
TypeBlog Post... polymerase and transcription factors. Since the promoter region drives transcription of a target gene...repressor then prevents transcription from occurring, which means that transcription is now OFF. We’ll...tetracycline-controlled transactivator (tTA). They fused TetR with the transcriptional activation domain VP16...other. For example, the GAL4 transcription factor cannot drive transcription from the QUAS promoter, and...and the QF transcription factor cannot drive transcription from the UAS promoter. This is important because...Repressible: An activator protein is bound, turning transcription ON. When a repressor binds the activator protein...cannot bind the promoter sequence anymore and transcription is turned OFF. Negative Repressible: A repressor... -
Multiplex Genome Editing with CRISPR-Cpf1
TypeBlog Post...the usual transfection drawbacks: transient expression and needing to work with a transfectable cell line...Cassettes transfection gRNAs expressed from a polycistronic transcript Requires co-transfection of Cas9...Cassettes transfection gRNAs expressed from a polycistronic transcript Requires co-transfection of Cas9 ...expression platforms: transfection, lentiviral transduction, and AAV transduction. In most of Zetsche ... rely on transfection of more than one vector to express the gRNAs and Cas9. Co-transfections can lead... GFP tag were transfected on a single plasmid. This is versus 2.4% of cells transfected with a pool of...multiple applications (in vitro, in vivo, transfection, viral transduction) for simultaneous multi-gene editing... -
All in a Twist: dsRNA
TypeBlog Post...Transcription, translation, and prone to degradation – those are the words that describe RNA! Double ...in our cells in the single strand form, but double stranded RNA and RNA:DNA hybrid molecules both exist...arise from a ssRNA engaging one strand of a dsDNA molecule; the 3-stranded structure produced is known as...intermediates in the process. These transcription-coupled R-loops are transient in nature and will dissociate...dissociate when gene transcription is complete. However, transcription of thousands of genes is constantly occurring...engages one strand of a dsDNA molecule, it does so at the expense of the unpaired DNA strand. A ssDNA molecule...Double stranded? Well, that’s just for DNA – right? RNA performs almost all of its biological functions in... -
AAVs CREATed for Gene Delivery to the CNS and PNS
TypeBlog Post...that increase transduction efficiency, none allow for simple and efficient transduction of both the CNS...capsids were packed with a GFP transgene and GFP intensity and transduction efficiency of neurons were measured... Table 1: Transduction efficiency of AAV-PHP.B versus AAV-PHP.eB in the CNS. A GFP transgene was packaged... Table 2: Transduction efficiency of AAV.9 versus AAV.PHP.S in the PNS. A GFP transgene was packaged...the generation of a transgenic mouse. 2. Cell-type-specific restricted transgene expression in the CNS...introduce a transgene into a specific cell type in the brain, you needed to make a transgenic mouse. Combining...AAV) vectors are the most frequently used gene-transfer tools in the study of the brain and spinal cord... -
Overcoming the Challenges of Lentiviral Production
TypeBlog Post...changing transfection ratios can affect transfection efficiency. For some transgenes, transfection optimization...containing structural genes and a transfer plasmid carrying the transfer gene. By dividing the viral elements... structural elements, envelope, and transfer gene are transfected into a packaging cell line, usually ...may not translate to the target cell line. To overcome this issue, we recommend using a range of doses...systems such that it no longer requires the viral transactivator, Tat. For more information on the different...requirement for additional DNA can impact the transfection efficiency of the packaging cell line and thereby...recommended that you try a few different ratios of transfer, envelope, and packaging plasmids in order to ... -
Hassle-free 96-well Format Epitope Tagging Using Cas9 Ribonucleoprotein
TypeBlog Post...binding to the template strand (strand used by RNA polymerase II for transcription) are more effective for...complex. This complete transfection mix, i.e. csRNP plus ssODN, is then transfected into stem cells. Cells... were transfected in 96-well format using an Amaxa Shuttle device; 5 days after the transfection, the ...template strand. Therefore, I suggest that picking a crRNA complementary to the template strand could increase...Prepare cells for transfection, add csRNP and ssODN to the cell suspension, transfect and let cells recover...selection of transfection buffer and electroporation pulse program to achieve high transfection efficiency... contact me at Pooran.Dewari@ed.ac.uk. Keep pipetting and happy genome editing! Pooran Dewari is a postdoc... -
Viral Vectors 101: AAV Variables That Matter
TypeBlog Post...., 2017), axonal transport (Murlidharan et al., 2014), and postsynaptic transmission (Oh et al., 2020... S. (2013). Analysis of Transduction Efficiency, Tropism and Axonal Transport of AAV Serotypes 1, 2, 5...Tetracycline-Dependent Transactivator Correlates with Long-Term Doxycycline-Regulated Transgene Expression in ...Specificity of gfaABC1D-Driven Transgene Expression in AAV-Mediated Gene Transfer. Molecular Therapy - Nucleic...great in a GABA neuron, for instance, may not transduce the adjacent norepinephrine neuron at all. There... more than one serotype that will efficiently transduce your cells. In fact, we usually recommend testing...primate. Likewise, in vitro efficacy doesn’t always translate to in vivo efficacy. You’ll therefore need to ... -
Mobile-CRISPRi: Bringing CRISPRi to Diverse Bacteria
TypeBlog Post...protocols can transfer CRISPRi into a single bacterial strain, such as a B. subtilis, or a narrow range of bacterial...can be introduced into a broader range of bacteria. Once transferred, Mobile-CRISPRi stably integrates...bacterial Tn7 transposon system. This system has two parts: a plasmid expressing the Tn7 transposition genes ...chromosomal copy of the RP4 transfer machinery mobilize these plasmids for transfer to recipient cells during...: A Tn7 transposon containing the CRISPRi components and a plasmid with the Tn7 transposition genes are...disease. However, the rate of transfer was variable. They measured transfer rates by comparing the number... P. mirabilis, had only ~1 transfer per 1,000,000 colonies. Higher transfer rates are better suited for... -
Hot Plasmids April 2018 - Protein Degradation, Nanoscopy, FIRE-Cas9, and Yeast Expression Tools
TypeBlog Post...expression, Aranda-Díaz et al transformed yeast with both a GAL4/estradiol controlled transcription factor ... a broad pH range. The four biometric probes successfully targeted endosomes under a range of pH conditions...ligand binding domains and the MSN2 transactivation domain. Transcription factor activation via the appropriate...progesterone controlled transcription factor as well as reporters specific to each transcription factor. They then...together. Aranda-Diaz et al additionally show that it is possible to use synthetic transcription factors... levels. That is, if transcription factor 1 controls expression of transcription factor 2, which directly...by modulating the induction of transcription factors 1 and 2. See Aranda-Díaz et al. for more information...