...editing machinery such as CRISPR-Cas. Figure 1: Schematic of targeted gene knock-out (left) and targeted...AdV-mediated transduction of gRNA:Cas9 ribonucleoprotein complexes into transformed and non-transformed cells...(right) are transduced to target cells. Within target cells, Cas9 machinery is transiently expressed and... viruses. Adenoviruses are non-enveloped double-strand DNA viruses with a genome of around 36 kb in size...left), a fragment is deleted from two homologous strands of DNA through error-prone non-homologous end joining...other viral vectors, AdVs can provide a large transgene packaging capacity. For instance, with a packaging...disruption frequencies in the various cell types ranged from 18% to 65% (Maggio et al., 2014). An alternative...

...Figure 1: A schematic illustration of CRISPR/Cas9-based approaches to study ncRNAs. (A) Transcription start...signal downstream of the transcription start site will terminate transcription of most of the ncRNA (Figure... coming, right? Non-coding RNAs (ncRNAs) are transcribed but do not encode proteins. They play important...Using a single guide RNA (sgRNA) to create a double-strand break works well because very small deletions and...sequence can completely disrupt expression of the transcribed ncRNA (Jiang et al. 2014).  Simple knock-out ...lncRNA regulatory elements that are crucial for transcription and downstream function. Rather than attempting...the lncRNA locus, scientists can mutate the transcription start site, splice sites, exons, and/or promoters...

...how the brain operates. References 1. Callaway EM. Transneuronal Circuit Tracing with Neurotropic Viruses...generally are not transmitted to adjacent neurons via synapses (i.e., transmitted transsynaptically). This is ...retrograde transmission (Etessami et al., 2000, Wickersham et al., 2007). Thus, RABV transsynaptic spread ...replicate. Modified Rabies Virus: Converting a transsynaptic neuronal tracer into a monosynaptic (first order...subsequent cycles of viral replication and retrograde transmission occur, spreading the virus through higher and...higher order neural connections. While this transsynaptic spread is useful for neuronal tracing, it has...-dependent TVA to Cre-expressing neurons in a transgenic mouse line. By doing this, RABV expressing the...

...genome engineering and microbiology.     References 1. Chen, Sean, et al. "Highly efficient mouse genome...:     Cells must be amenable to transfection or viral transduction     Appropriate promoters must be...expression     The requirement for Cas9 transcription and translation delays editing What are Cas9-gRNA ... studies in cells that are difficult to transfect or transduce. While using Cas9-gRNA RNPs may require...site of interest. This is commonly performed by transfecting cells with a plasmid, such as PX459, which encodes... often be used in cells that are difficult to transfect, such as primary cells. Using RNPs can also alleviate... are detectable at high levels shortly after transfection, and are quickly cleared from the cell via protein...

... NGT PAM GAA PAM GAT PAM xCas9 3.7 41 (1) 32 (1.6) 13 (2.1) 38 (4.5) 7.2 (5.2) ...xCas9 for transcriptional regulation and base editing Hu et al. also engineered transcriptional activators...activating transcription. Sites containing NG, GAA, or GAT PAMs averaged 56-91% transcriptional activation... to create xCas9, an enzyme recognizing a broad range of PAMs like NG, GAA, and GAT, but also displaying...subunit ω. This construct is designed to activate transcription from the accessory plasmid (AP) encoding phage...could recognize a library PAM, it would induce transcription of gene III, permitting phage propagation and...spectinomycin resistance. xCas9 3.7 showed the broadest PAM range, recognizing NG, NNG, GAT, and CAA PAMs, while xCas9...

...target DNA quickly and accurately.  Figure 1: Steps in PCR reaction   This process of denaturation...separation of the two DNA strands.  Annealing- The temperature is then dropped to a range in which the forward...the primers can anneal to the single stranded DNA template strands. DNA polymerase is also stable at this...template DNA to amplify from and unique single stranded DNA primers that bind upstream (5’) and downstream... process as DNA polymerases require an existing strand of DNA to add nucleotides to.  Using these reagents...reaction:  Denaturation- To amplify DNA, the two strands of the template DNA first have to be separated....used to quantitate RNA levels using reverse transcription-qPCR (RT-qPCR). The first step of this process...

...in restraint. The very first subheading in Chapter 1 asks “What is science?” That’s a very big question... that may have warranted their own chapters, and certainly chapters that could warrant their own books..., and he wisely makes no such attempt. He is transparent about his own biases--many of which will be shared...non-scientists, Zimmer’s observations will likely range from mildly surprising to genuinely shocking. Mainstream...he describes the now infamous tale of Rosalind Franklin and her essential-but-unlauded role in the identification...within this section. The GFP story has its own Franklin in Doug Prasher, who originally isolated the GFP...science produced by the quieter, more reserved Franklins and Prashers will find it increasingly difficult...

...(RBD) of the viral spike protein.   Figure 1. (A) SARS-CoV-2 RBD DMS Library generation and sequencing... lab has created a novel nanocompartment for transporting proteins in yeast by using murine polyomavirus...2A-Synaptophysin-mRuby from Liqun Luo’s lab expresses membrane tethered GFP to enhance axonal labeling and synaptophysin-tagged...expressing GCaMP6f with this promoter. Image calcium transients in PV interneurons with AAV-S5E2-GCaMP6f are ...

...understand these strange results by digging deeply into their data.     Fig. 1: Genomic fraction...Samples are divided into those of African ancestry(orange) and those of other ancestry groups (grey). ...): 250-252. Carlson J, Henn BM, Al-Hindi DR, Ramachandran S. Counter the weaponization of genetics research...

...before you can start transducing your virus. Let’s start there!     Figure 1: Flowchart showing...optimized your transduction conditions, you’re ready to transduce! Addgene has a transduction protocol you... the pooled library is transformed into E. coli for amplification. Transformed E. coli are allowed to ...functional titering and optimize transduction efficiency. Transduction efficiency can vary with titer, ...cells to transduce, you may want to consider spinfection. Spinfection is the process of transducing cells...this post, I’ll walk you through how to prep and transduce your pooled library.  Pooled libraries Scientists...sequencing to confirm library representation. Transfection of the DNA pooled library and appropriate packaging...

...mammalian expression from human elongation factor 1 alpha Constitutive  Tends to give consistent expression...tetracycline operators. Transcription can be turned on or off depending on what tet transactivator is used. UAS...for in vitro transcription, the promoter drives either the sense OR antisense transcript depending on ...This element is responsible for initiating the transcription of your insert into RNA. In practice, the term...controls the binding of the RNA polymerase and transcription factors, therefore promoters play a large role...

...necessary.   Tips for barcoding and tracking samples 1. Start with the tube - Barcoded tubes come in many...packages have spent days to weeks in transit and some have been transported across oceans and continents. Each... treated to easily take in plasmids (transformation). Transformed bacteria are then grown up on antibiotics...received is immediately transformed and stored. Some samples need to be transformed with a micropulser using... performs an average of 140 transformations. The lab typically transforms newly deposited samples from...delivered by a mail courier and then the journey of transformation and storage begins. Some samples are submitted...long-term storage in our facilities, every sample is transferred to a 2D barcoded tube (see next section) and ...

... such a popular model organism? Zebrafish (Figure 1) were initially recognized as a useful vertebrate ...strategy uses a transposon called Tol2 to randomly integrate foreign DNA into the genome. Non-random integration...et al., 2019). Generating zebrafish transgenics Creating transgenic organisms by introducing foreign DNA...Danio rerio) have been used since the 1930’s in a range of biological studies, including investigations ... to produce abundant, externally fertilized, transparent progeny (Figure 2). These features give it a ...individual to maintain. Also in contrast to mice, the transparent zebrafish embryo develops outside of the mother...sequenced genome also permits “whole-genome/transcriptome” studies, in which, for example, the activity...

...impacts of neural circuits on behavior. Figure 1: An overview of the chemogenetics system. Why use...approved drugs so that your results are viable for translation to human patients. Picking receptors The receptor... specifically designed Gi-coupled receptor in transgenic mice. Nature Biotechnology 17:165–169 . https...

...inclusion bodies and is folding properly. References 1. Angov, Evelina, et al. "Heterologous protein expression...structures in RNA transcripts Effects on transcription (remember, it’s not all about translation - e.g. codon... you cannot choose among the possible codons at random and expect your sequence to express well in any...therefore may need fewer resources for the entire translation process. For example, during high growth rate... tRNAs. For example Tuller et al. found that translation efficiency is well correlated with codon bias...tRNAs, different regions of the protein may be translated at different rates. The ribosome will move quickly...the ribosome stalls, this may give the swiftly translated regions a chance to fold properly. For example...

... education and scientific writing.     References 1. Martz, Colin A., et al. "Systematic identification...’s group at the University of California, San Francisco, is approaching the Ras problem by exploiting ...lines. Further, for each plasmid in the kit, the transcript most commonly found across all TCGA tumor samples...

...plasmids are passed down through generations (Figure 1). These so called “plasmid addiction systems” require...required for hok translation. Here, Mok and Hok translation is coupled. Translation from the Shine-Dalgarno...more stable than the methyltransferase. When a plasmid is lost, the methyltransferase is degraded and/or...systems have been used as biological tools for a wide range of applications in molecular biology or in vivo ...ccdB gene die off and a higher percentage of transformants contain the ccdB-less construct. Other toxin-antitoxin...composed of restriction endonucleases and methyltransferases. Restriction endonucleases cleave DNA at ...specific nucleotide sequences. To counter this, methyltransferases add methyl groups to bases at specific nucleotide...

...such as model systems and primary cells. References 1. Doench, John G., et al. "Rational design of highly...prevent efficient transcription from sgRNA targets. CRISPRi is effective in a narrow range around the transcription...two sets of sgRNAs; A, the top 3 ranked sgRNAs, and B, the next 3 ranked sgRNAs. Dolcetto was able to discriminate...Cas9 derivatives. Unmodified Cas9 causes double stranded DNA breaks that commonly result in a complete ... lab selected sgRNAs in this optimal window and ranked them based on their optimized sgRNA rules and potential...gene expression, dCas9 can also be used for transcriptional activation. Activation of specific genes allows... strategies have been developed to recruit transcriptional machinery to dCas9 and its RNA directed binding...

...determine purity of the AAV preparation. Figure 1: Silver staining of purified and non-purified AAV ...of Pennsylvania Vector Core. Transfections are performed using the transfer plasmid, a plasmid encoding...PCR with primers targeting the transfer plasmid used in the transfection. PCR products are analyzed by ...cell cultures are inspected for sterility. Transducibility Some viral vectors are tested in vitro and ...images).     Figure 2: AAV Pro cells were transduced with either pAAV-Ef1a-mCherry-IRES-Cre (55634...filtration through a 0.45 µm polyethersulfone (PES) membrane. The preparations are then aliquoted, frozen, ...from Wang et al., 2018). Briefly, 293T cells are transduced with serial dilutions of a lentiviral vector,...

...antibiotic selection. Essentially, this gene is a 2-in-1 providing both bacterial and eukaryotic selection,...in a plasmid. During the propagation and/or transformation process, some bacteria will either never receive... is nifty because the recovery period after transformation (the dreaded 60 minutes shaking at 37 degrees... available, cost-effective, timesaving for transformations. Cons: Prone to satellite colony formation ..., interchangeable with Amp, timesaving for transformations. Con: Expensive.   Kanamycin Kanamycin, or...selection gene. However, it does require a slower transformation recovery period than amp or carb (60 minutes...confers mammalian resistance to G418. Con: Slow transformation   Spectinomycin/streptomycin Spectinomycin...