...Components of CRISPR  xCas9: Engineering a CRISPR Variant with PAM Flexibility Cas9 vs the Other Cases Further...the basic parts of the Cas9 enzyme.   Figure 1: A cartoon depiction of Cas9’s two major lobes, REC...   Unbound Cas9 Now that we know what we’re looking at, let’s peek at unbound—“apo”—Cas9 from Streptococcus...residues in this loop to produce SuperFi-Cas9, a high-fidelity variant that still retains high cleavage efficiency...Figure 8: Comparison of Cas9:RNA crystal structure (left, PDB ID 4ZT0) with Cas9:RNA:DNA electron microscopy... with a nearby protospacer-adjacent motif (PAM)? Cas9 is becoming an ever more ubiquitous tool for genome... bridge helix. Created with BioRender.com.   Cas9 has two major lobes, called NUC (for nuclease) and...

...Expanding the base editing scope in rice by using Cas9 variants." Plant biotechnology journal (2018). PubMed...by tethering cytosine deaminase with Cas9 nickase (nCas9). nCas9 creates a nick in the DNA by cutting ...Nickase Cas9 (D10A) Deaminase PAM requirements Reference CBE SpCas9 rAPOBEC1 NGG 6 SpCas9 Target-AID...target genomic locus/loci, choose a base editor variant from Table 1 depending on the PAM sequence. Avoid...Bastian Minkenberg, and Yinong Yang. "Boosting CRISPR/Cas9 multiplex editing capability with the endogenous...Targeted base editing in rice and tomato using a CRISPR-Cas9 cytidine deaminase fusion." Nature biotechnology...Precise base editing in rice, wheat and maize with a Cas9-cytidine deaminase fusion." Nature biotechnology...

.... Repair of Cas9-induced breaks by NHEJ As illustrated below, NHEJ-mediated repair of Cas9-generated breaks... 2020). NHEJ can also be engaged by variants of the canonical Cas9 approach. A pair of CRISPR guides that...Cas system for genome engineering is the fact that Cas9 can be easily programmed to make a DNA double strand...discuss NHEJ, and how it impacts what happens to Cas9-mediated DSBs in the genome. Non-homologous end...consequently the principal means by which CRISPR/Cas9-introduced breaks are repaired. The following factors...introduce indels. Given the end structure of the Cas9 DSB (blunt or near-blunt ends without nucleotide...population of cells constitutively expressing a targeted Cas9 should possess indels in the majority of their chromosomes...

...fully functional Cas9 upon dimerization. Splitting wild-type Cas9 into n-terminal (Cas9(N)-2xNLS) and c-terminal... can write a blog post about it! Split Cas9 system The Cas9 protein is composed of an n-terminal DNA... the bi-lobed architecture of Cas9 to engineer a series of "split" cas9 molecules that cannot function...activation, the c-terminal cas9 fragment was fused with FK 506 binding protein 12 (Cas9(C)-FKBP-2xNLS) and the... the n-terminal cas9 fragment with FKBP rapamycin binding domain of mTor (Cas9(N)-FRB-NES) resulting in...rapamycin-inducible Cas9 for genome editing. Without rapamycin treatment, the Cas9(N)-FRB-NES fragment...sequence. Treatment with rapamycin induces Cas9(N)-FRB-NES and Cas9(C)-FKBP-2xNLS dimerization and net influx...

...enzyme, the development of SaCas9, NmeCas9, Cas12a enzymes, and engineered variants thereof offers additional... capacity of a locus. When using S. pyogenes Cas9 (SpCas9), potential target sites are both [5’-20nt-NGG... (inhibition) technologies – a nuclease-dead Cas9 (dCas9) is directed near the promoter of a target gene...with CRISPR technology is usually accomplished by Cas9-mediated dsDNA breaks: following a cut, the error-prone...to the intended edit rather than some passenger variant that came along with the single cell clone (although...even more exquisite for the so-called base editor Cas9, which makes DNA changes in the absence of dsDNA...2019) Agreement between two large pan-cancer CRISPR-Cas9 gene dependency data sets. Nat Commun 10: . https...

...continuation of that work, they have found at least two variants that display increased neuronal expression in ...side effects, by allowing the user to select for variants that infect the CNS while selecting against those...of up to 20%, comparable to commonly used CRISPR/Cas9 methods for large inserts. However, this system ...in comparison to the 62-90% error rate seen with Cas9 editors. The lab believes that this system could...inactive dCas9 and microbial SSAPs (dCas9-SSAP) which insert genes in a cleavage free manner. The dCas9-SSAP...cleavage-free dCas9-based gene editor using microbial SSAPs. Image from Wang, et al, 2022.  Find dCas9-SSAP...Cre-mediated AAV Targeted Evolution method (M-CREATE) dCas9-SSAP with reduced error rate for long sequence knock-ins...

...using CRISPR and Wednesday will highlight some Cas9 variants. Next, we’ll look at various CRISPR applications...

...sequence targeted by the Cas9 nuclease. The Streptococcus pyogenes Cas9 (SpCas9) requires an NGG PAM to...range of CRISPRCas9 by engineering SpCas9 Article contributed by Shreya Vedantam CRISPR/Cas9 is widely...increased versatility of the engineered SpCas9-NG and its variants can be used to engineer specific sites...  The Kanemaki lab previously developed a CRISPR/Cas9 based method to tag endogenous proteins in HCT116...widely used genome editing tool. However, Cas9’s endonuclease activity can be limited by the need for a specific...recognize the target. Osamu Nureki’s lab engineered SpCas9 (SpCas9-NG) with relaxed preferences for the third ...NGG. In addition to the engineered SpCas9, they also fused the SpCas9-NG with the activation-induced cytidine...

...different strategies with CRISPR-Cas9. There are so many different variants and strategies out there. This...pluripotent stem cell (iPS) technology and CRISPR-Cas9 constructs from Addgene to gene-edit mutations into... of those mutations, they now plan to use CRISPR-Cas9 technology to create cell lines and/or mouse models...ve proposed to use plasmids with modified nickase Cas9 protein in order to target the specific gene region...

...populations that already express Cas9 from an unlinked locus, while a Cas9+sgRNA drive targeting a synthetic...residual sgRNAs and possibly cas9 gene). An immunizing reversal drive is a variant that also spreads through...School. Scientists making transgenic organisms with Cas9 should be aware of the potential hazards of creating...caution. Why does making transgenic organisms with Cas9 risk creating a gene drive? The simplest way to ...last year2, delivering a DNA cassette encoding the cas9 gene and single guide RNAs (sgRNAs) with appropriate...easiest: don't use a DNA vector that encodes both Cas9 and sgRNA. What if I want to work with gene drives...underlying advance enabling RNA-guided gene drives is Cas9 genome editing. Finally, gene drives are an inherently...

...Best Cas9 Variant for Your Next Experiment Find out More about Genome-wide Screens with CRISPR/Cas9 Learn...CRISPR/Cas9 is an enormously plastic tool and has taken the scientific world by storm. While Cas9 has been...required for Cas9-based activation. CRISPRa for genome-wide studies One of the best uses for Cas9 activators...context of the gene, Cas9 activators efficiently solve these problems.   Which Cas9 activator should I ...with AAV Resources on Addgene.org Find Cas9 Activators Find Cas9 Repressors Catch Up on Your CRISPR Background...there has also been significant work on constructing Cas9 transcriptional activators. These constructs allow...upregulation of essentially any gene by fusing mutants of Cas9 deficient in DNA cutting activity to a transcriptional...

...one AAV, Cas9 must be made smaller. Previous attempts to “shrink” Cas9 include the use of St1Cas9 (~3.3 ...amino acids in length, Cas9 from Campylobacter jejuni (CjCas9) is the smallest Cas9 ortholog characterized...vehicle for Cas9. However, to allow for more room for regulatory sequences while still fitting Cas9 and its...equally potent Cas9 protein, the Zhang lab took a different approach. They analyzed over 600 Cas9 orthologs...Resources on the Addgene Blog Learn more about Cas9 Variants and the Expanded CRISPR Toolbox Read about CRISPR... aureus Cas9 (SaCas9, 1053 amino acids) displayed cleavage activity in mammalian cells. SaCas9 produced...truncated Cas9. Unfortunately, certain drawbacks limit the utility of these systems: St1Cas9 requires ...

...efficiently, they’ve recently adapted the CRISPR/Cas9 system for protein tagging. We spoke with Mendenhall...context? Mendenhall: The benefits are two-fold: CRISPR/Cas9 offers high efficiency of inducing double strand...technologies. Generally speaking, anyone using CRISPR/Cas9 in the lab already should be able to run this protocol...be doing something similar. There may be other variants of this that are better for some experiments than... crispr/cas9... cas9...

...CRISPR-based genetic screening methods have primarily used Cas9 to knock out genes, researchers at the Genetic Pertubation... a single expression cassette is advantageous to Cas9’s larger expression requirements (Figure 1), but...optimizing enzyme activity using an enhanced Cas12a variant (enAsCas12a), minimizing off-target effects by ... guides. While two guides require two arrays for Cas9, two guides can be streamlined into a single array...-wide library capable of performing similarly to Cas9 screens in a compacted library. Overall, Cas12a’...CRISPR-Cas effectors and fusion proteins, such as Cas9 and Cas12a, creates challenges for in vivo delivery...529 amino acids, less than half the size of either Cas9 or Cas12a. Despite its small size, CasMINI is comparable...

...technology. Nano-lanterns contain a Renilla luciferase variant fused to an FP; when supplied with a luciferase...BRET). Photons emitted by a Renilla luciferase variant are used to excite the fused fluorescent protein... endogenous protein fusions created using CRISPR/Cas9. eNLs offer high luminescent signal for imaging ...Addgene. Suzuki, Kazushi, et al. “Five colour variants of bright luminescent protein for real-time multicolour...

... Check out this post to see if an engineered Cas9 variant might work for your experiment. PITChing MMEJ...Corn’s lab describe how a better understanding of Cas9 biophysics can help enhance HDR. CRISPR 101: Ribonucleoprotein...tool to help you design, pick, and close guides for Cas9 and Cpf1. This tool supports over 250 genomes, and...The PAM Requirement and Expanding CRISPR Beyond SpCas9 The closer your edit is to the PAM site, the higher...

... a colorful Cas9 toolbox, Ma et al. turned to SpCas9 and its orthologs NmCas9 and St1Cas9. Each ortholog...locus, and to do so in vivo. Catalytically dead Cas9 (dCas9) cannot induce gene editing, but it retains its...the other orthologs. Ma et al. tested their dCas9 variants using gRNAs specific for telomeric sequences...success of Ma et al.’s approach, fluorescently labeled Cas9’s come with a number of limitations. Since color...by PAM sequence, each color requires a different Cas9 ortholog, and the target sequence must be located...genome editing. If used with catalytically active Cas9, the short, CRISPRainbow gRNA will permit labeling...publication at Addgene. 4. Kiani, Samira, et al. “Cas9 gRNA engineering for genome editing, activation ...

...pDGE Dicot Genome Editing Kit contains Cas9, Cas9 nickase, and Cas9 activator expressing plasmids that can...CRISPR-Cas9-based tool for targeting CpG methylation by fusing catalytically inactive Cas9 (dCas9) with...high-throughput CRISPR/Cas9 gene modification in Caenorhabditis elegans CRISPR/Cas9 technology has revolutionized...reported on a novel Cas9-based activator developed by the Church lab, termed “dCas9-VPR”, which facilitates...gRNA expressing cells were then transfected with a Cas9-expressing plasmid to generate a population of mutant...post entitled “Genome-wide Screening Using CRISPR/Cas9”. Detailed information regarding the Wu Lab library...gene was chosen to represent the primary splice variant in 38 types of human cancer. Many of the transcripts...

...Screening immune cell lineages in vivo using the CRISPR-Cas9 system CHIME Article contributed by Aliyah Weinstein...custom nucleases for each gene of interest. CRISPR-Cas9 tools have been used in immunology for in vitro ...Medical School developed a solution: CHIME, a CRISPR-Cas9 system that can edit genes in any immune lineage...in vivo, the non-immunogenic violet-excited GFP variant Vex. To understand the impact of this gene editing...expressed this construct in bone marrow stem cells from Cas9-expressing mice, and used the cells to reconstitute...

...CRISPR Antimicrobials Day 7: Multiplexing and Cas9 variants: CRISPR 101: Multiplex Expression of gRNAs and...Pooled libraries: Genome-Wide Screening Using CRISPR/Cas9 and Plasmids 101: NGS Quality Control for Pooled... CRISPR Targeting Specificity with eSpCas9, SpCas9-HF1, & HypaCas9 Day 10: Transcriptional regulation:...The PAM Requirement and Expanding CRISPR Beyond SpCas9 Day 8: Repair mechanisms: CRISPR 101: Non-homologous...

...the Addgene Blog Learn about High Fidelity Cas9 Variants How to Design Your gRNA Delivering CRISPR Ribonucleoproteins...at the Rockefeller University in NYC. The CRISPR/Cas9 system is a versatile tool for precise gene editing...organisms and model systems. We have used CRISPR/Cas9 extensively for the purpose of making sequence-specific...induced pluripotent stem cells (iPSCs). The CRISPR/Cas9 com­plex is very efficient at introducing double...Cas-blocking mutations After genome editing with CRISPR/Cas9 in human cells was described in 2013 (Cong et al...amounts of single cell clones. Furthermore, CRISPR/Cas9 editing is often bi-allelic, meaning that even if...systematically analyzed: introducing silent CRISPR/Cas9 blocking mutations in either the PAM (changing one...

...such as long or highly structured templates. Cas9 variants PE6e–g often had even higher editing efficiencies...vivo. Incorporating reverse transcriptase (RT) variants, PE6a and PE6b are 500–800 bp smaller than previous...PE6d are optimized for dual-AAV systems. These variants use different RT enzymes and performed large edits...edit.   Figure 1: Choosing the best PE6 variant for your application. Image reused form Doman and...

... activation CRISPR activation uses dCas9, a CRISPR protein variant lacking its endonuclease ability, to...J, Collins JJ, Church GM (2015) Highly efficient Cas9-mediated transcriptional programming. Nat Methods...Perrimon N, Collins JJ, Church G (2016) Comparison of Cas9 activators in multiple species. Nat Methods 13:563...transcriptional activation by an engineered CRISPR-Cas9 complex. Nature 517:583–588 . https://doi.org/10.1038...Gersbach CA (2013) RNA-guided gene activation by CRISPR-Cas9–based transcription factors. Nat Methods 10:973–... cell lines.   dCas9-VP64 Description CRISPR activation can occur through fusing dCas9 with VP64, a strong... for CRISPR-based gene activation. dCas9-CBP In this method, dCas9 is fused to CBP, an histone acetyltransferase...

...time CRISPR users Learn how to Choose the Best Cas9 Variant for Your Next Experiment Learn More About Designing...Additional Resources on Addgene.org Find Other Cas9 Variants for Purifying Genomic Regions of Interest Here...co-expressed, the gRNA targets the dCas9 to the loci of interest and dCas9 is biotinylated by BirA. From here...To increase the resolution, the Xu lab created a dCas9-based CAPTURE (CRISPR Affinity Purification in situ... cell line that co-expresses three components: dCas9 with an added biotin acceptor site BirA, a biotin...be pulled down via streptavidin IP. Biotinylated dCas9 goes along for the ride throughout all of these ... CAPTURE cell lines will have varying levels of dCas9 and gRNA expression. Additionally, CAPTURE 3C-based...

...option is to use variants of Cas9, like split Cas9, or a smaller Cas9 ortholog like SaCas9. You could even...at double-stranded break points caused by CRISPR-Cas9 editing. The good news is that this integration ...approximately 4.7 kb — which means that when using Cas9, you’re already almost out of space! Don’t let this... you have one AAV vector dedicated to expressing Cas9, while the other houses the gRNA and scaffold. If...even venture away from the comfort of Cas9, and opt for a completely different Cas effector, like Cas12a...

... eSpCas9(1.1), or HypaCas9. Read more about Cas9 options in our blog post here. Dealing with low editing...version of Cas9 that has been specifically engineered for reduced off target editing, such as SpCas9-HF1, eSpCas9...gRNA and introduced it into your target cells with Cas9. Hooray! Now it’s time to make sure your genome ... product of both an unedited population and your Cas9-targeted cells. Simply upload both trace files to...with the estimated editing frequency of your sgRNA-Cas9 combo. Pro tip: When designing your PCR, ensure ...introduced a donor template along with your gRNA and Cas9 combo and are hoping for homology-directed repair...despair, you have options! If you think delivery of Cas9 or gRNA is the issue, check out or blog on optimizing...

...CRISPR-Cas9 genome editing may be the hot new way to manipulate gene expression, but other gene manipulation...expression; these deletions are defined using 2 loxP variants (only identical loxP sites can mediate recombination...either deletion removes one of the other loxP site variants, preventing further recombination. Brainbow-1.1...with recombination events specified by three loxP variants, but the principles remain the same. The first...Variations Between Brainbow Systems   Brainbow variants and applications beyond the mouse brain In addition...Brainbow to be used in a variety of species. More variants have been created by other labs, including R26R-Confetti...

...Use Cas9 Activators Perform Genome-Wide Screens with CRISPR Generate Mouse Models with CRISPR/Cas9 Additional...techniques, please see “Methods for Optimizing CRISPR-Cas9 Genome Editing Specificity” by Tycko et al. 2016...improving the genome-wide specificities of CRISPR–Cas9 nucleases”
by Tsai and Joung 2016. Many thanks ...high-throughput screening strategy for detecting CRISPR-Cas9 induced mutations using next-generation sequencing...sequencing: a comparison of methodologies for KRAS variant detection." Biotechniques 53.3 (2012): 182-188....of off-target DNA cleavage reveals RNA-programmed Cas9 nuclease specificity." Nature biotechnology 31.9.... "Digenome-seq: genome-wide profiling of CRISPR-Cas9 off-target effects in human cells." Nature methods...

...fluorescent protein to various Cas9 variants, SpCas9, NmCas9, and St1Cas9. These fusions localized to specific...The catalytically dead Cas9 protein (dCas9) is well known for its ability to bind DNA targets without...inhibition, among others. Over the past few years, dCas9 has also become a robust visualization tool to study...University of Massachusetts Medical School developed a dCas9-based multicolor labeling system to visualize chromosomal... al. “Multiplexed labeling of genomic loci with dCas9 and engineered sgRNAs using CRISPRainbow.” Nature...

... years, scientists have utilized CRISPR-Cas9 protein variants, Cas13, and Cas12a, to develop simple, portable...Cas12a (Cpf1) is a CRISPR Cas variant that can also cleave dsDNA similarly to Cas9 (Zetsche et al., 2015 )....

...for oxidizing environments to photoconvertible variants, it seems like GFP is always learning new things...proteins with a modular structure, constructing split variants should be relatively straightforward, but it is...versions of non-modular proteins like Cre. Could Cas9-DOG be developed soon to allow genome modification...

...plasmids available! Interested in purifying Cas9? Check out pET-28b-Cas9-His from Alex Schier's lab, designed...the lab of Yonglong Chen, pCS2-3xFLAG-NLS-SpCas9-NLS is a Cas9 expression plasmid that was used by Chen...colleagues, FokI-dCas9 expresses Fok1 nuclease domain fused to catalytically inactive Cas9 DNA-binding domain...which is 45 nm more red-shifted compared to other variants. The group further optimized Chrimson through ...off-kinetics (15.8 ± 0.4ms from 21.4 ± 1.1 ms); this new variant was named ChrimsonR. Plasmids containing Chronos...lentiviral and AAV expression vectors for certain variants. Klapoetke et al., Nat Methods 2014 Mar 11;(...gene/region of interest is a key step for CRISPR/Cas9 gene editing. Dr. Masahito Ikawa has created a GFP...

...Gram-positive bacteria (Kellenberger et al., 2013). Other variants of Spinach include Baby Spinach, a miniaturized...cellular RNA to specific intracellular locations using Cas9 and track the localization of the complex. Broccoli...short non-coding RNAs (Autour et al., 2018). Three variants of Mango, coined Mango II, III, and IV, were then...high binding affinity to TO1-biotin. Two of these variants exhibit increased brightness compared to Mango...

...editors use either catalytically dead Cas9 (dCas9) or a Cas9 nickase (nCas9) to avoid introducing double-strand...need from Cas9 are sequence specificity and the R-loop structure. In order to bind DNA, Cas9 requires ...expanded CGBE target scope by creating BE variants with other Cas9s that recognize different PAMs. Their computational...non-target strand of DNA for Cas9 to bind.   R-loop The structure formed by Cas9 binding to DNA and separating...PAM) on the opposite strand. Once it finds a PAM, Cas9 unwinds the adjacent DNA to create a region of separate...single-stranded DNA (ssDNA) region, using enzymes fused to Cas9 to alter the exposed ssDNA bases. Thus, base editors...window restricted to the stretch of ssDNA created by Cas9 binding. Pro tip! In CRISPR, the non-target strand...

... samples. Ma et al. designed plasmids containing Cas9 and two different gRNAs, and electroporated them...genome sequencing in selected control and CRISPR-Cas9 injected embryos. In all cases, they did not observe...CRISPR Topic Page Read about High Fidelity CRISPR Variants Target Multiple Genes at Once with CRISPR Resources...

...using CRISPR/Cas9 to edit a gene, the expression of Cas9 is no longer necessary. However, Cas9 can be toxic...like creating stable cell lines, delivering CRISPR/Cas9 to cells for genome editing, and introducing inducible...Leavitt et al., 1996), and since then, numerous variants have been developed with different mechanisms ...

...2010 Yuhai Cui Red mScarlet Split-wrmScarlet variant of mScarlet Split-wrmScarlet and split-sfGFP: tools...-10) and sfCherry2(11), also photo-activatable variant PAsfCherry2(1-10) Improved split fluorescent proteins...Split-horseradish peroxidase (Alice Ting Lab 2016)  Split-Cas9 for inducible genome editing (Feng Zhang Lab 2015...

...Blainey’s lab has developed a multiplexing approach to Cas9-based pooled CRISPR screens called CROPseq-multi...Anzalone et al., 2019, including modifications to the Cas9 or reverse transcriptase enzymes, inhibition of ...end of the pegRNA, which is not well protected by Cas9. This is similar to the proposed mechanism for engineered...domain conferred several new improvements. The new variant has increased signal-to-noise ratio and better ...of applications, including CRISPR activation by dCas9-VPR, prime editing, and delivery of disease-relevant...

... line knock-ins of patient mutations which are variants of unknown significance – mutations with unclear...CRISPR 101: Making a Knock-In Cell Line Using CRISPR-Cas9 to Edit Disease Out of the genome Tips for a first...

...) model consists of a catalytically dead Cas9 protein (dCas9) that lacks endonuclease activity coupled...effectively change metabolic flux. The dCas9 protein and orthogonal variants can be used as regulatory ON/OFF.... Using dCas9 as an on/off switch The multiple scRNAs all individually utilize the same dCas9 protein....modulate dCas9 expression, multiple scRNA transcriptional programs can be regulated with dCas9 as a master...an orthogonal dCas9 protein that will still recognize guide RNA but with a different dCas9 binding module...specific proteins via aptamer domains. Combined with dCas9, this new scaffold RNA (scRNA) will bind to a PAM-adjacent...layered with distinct programs controlled by each dCas9 regulatory switch. By no means limited to the field...