GeneHero CRISPR Products and Services | Genecopoeia

Posted: June 7, 2018 at 3:40 am

GeneCopoeia’s GeneHero CRISPR-Cas9 products and services provide a complete, powerful solution to your genome editing needs. Products and services include:

CRISPR Plasmids. Transfect cells with our CRISPR plasmids with Cas9 and sgRNA for human, mouse, and rat. Search our database of more than 45,000 human, mouse, and rat genes for genome editing using CRISPR.

CRISPR Lentivirus.Genome integration of CRISPR elements using lentivirus. Cas9 and/or sgRNA packed in purified lentiviral particles at 108 TU/ml, ready to infect all cell types.

CRISPR AAV.Episomal expression of CRISPR components with adeno-associated viralparticles carrying Cas9 and/or sgRNA, excellent for tissue and animal transduction.

Cas9 Stable Cell Lines.Premade Cas9-expressing stable cell lines are great for sgRNA library screening and other high-throughput CRISPR-Cas9 applications.

The clustered, regularly interspaced, short palindromic repeats (CRISPR) system is bacterial immunity mechanism for defense against invading viruses and transposons. This system has been adapted for highly efficient genome editing in many organisms. Compared with earlier genome editing technologies such as zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), CRISPR-Casmediated gene targeting has similar or greater efficiency. Genome editing has been used for numerous applications, as shown in Table 1.

Table 1. Applications for CRISPR-mediated genome editing.

In the type II CRISPR systems, the complex of a CRISPR RNA (crRNA) annealed to a trans-activating crRNA (tracrRNA) guides the Cas9 endonuclease to a specific genomic sequence, thereby generating double-strand breaks (DSBs) in target DNA. This system has been simplified by fusing crRNA and tracrRNA sequences to produce a synthetic, chimeric single-guided RNA (sgRNA). The sgRNA contains within it a 20 nucleotide DNA recognition sequence (Figure 1).

Figure 1. Mechanism of CRISPR-Cas9-sgRNA target recognition and cleavage.

When the Cas9-sgRNA complex encounters this target sequence in the genome followed by a 3 nucleotide NGG PAM (protospacer adjacent sequence) site, the complex binds to the DNA strand complementary to the target site. Next, the Cas9 nuclease creates a site-specific double-strand break (DSB) 3-4 nucleotides 5′ to the PAM. DSBs are repaired by either non-homologous end joining (NHEJ), which is error-prone, and can lead to frameshift mutations, or by homologous recombination (HR) in the presence of a repair template (Figure 2).

Figure 2.CRISPR-Cas9-based gene engineering. Left. DSBs created by sgRNA-guided Cas9-mediated cleavage are repaired by NHEJ. Right. DSBs created by sgRNA-guided Cas9 nuclease are repaired homologous recombination between sequences flanking the DSB site, thereby causing “knock in” of sequences on a donor DNA.

While the CRISPR system provides a highly efficient means for carrying out genome editing applications, it is prone to causing off-target indel mutations. Off-targeting is caused by the ability of the Cas9- sgRNA complex to bind to chromosomal DNA targets with one or more mismatches, or non-Watson-Crick complementary. The propensity of CRISPR for off-target modification is a significant concern for some researchers who want to avoid results that are potentially confounded by off-target modification, as well as for those who might be interested in developing CRISPR for gene therapy applications.

Several strategies have been employed to mitigate CRISPR’s propensity for off-target genome modification. One such strategy is to use double nickases to create DSBs. The Cas9 D10A mutant is able to cleave only one DNA strand, thereby creating a “nick”. When two sgRNAs that bind on opposite strands flanking the target are introduced, two Cas9 D10A nickase molecules together create a staggered-cut DSB, which is then repaired by either NHEJ or HR (Figure 3). The double nickase strategy has been shown to greatly reduce the frequency of off-target modification. However, double nickases are limited in utility by design constraints; the sgRNAs must be on opposite strands, in opposite orientation to one another, and display optimal activity when spaced from 3-20 nucleotides apart. In addition, the cleavage activity of double nickases tends to be lower than that of standard Cas9-sgRNA. Further, nickases can still cause some degree of off-target indel formation.

Figure 3. General scheme of Cas9 double-nickase strategy. From Ran, et al. (2013). Two additional strategies, the use of truncated (17-18 nucleotide) sgRNAs, as well as a Cas9-FokI fusion, also dramatically reduce CRISPR-mediated off-target genome modification. However, these methods suffer from even further reductions in on-target activity and/or more severe design constraints compared with the double nickase approach.

Recently, two groups demonstrated that engineering Cas9 variants carrying 3-4 amino acid changes virtually eliminates CRISPR off-target genome modification. These variants still retain high on-target activity, without the design constraints of previous approaches, providing a promising alternative for high-fidelity CRISPR-mediated genome editing.

Watch recorded webinar / Download slides Title: Genome Editing: How Do I Use CRISPR? Presented Wednesday, February 22, 2017

Genome Editing-the ability to make specific changes at targeted genomic sites-is fundamentally important to researchers in biology and medicine. CRISPR is a very widely-used method for modifying specific genome sites, and can be used for many applications, including gene knock out, transgene knock in, gene tagging, and correction of genetic defects. However, researchers are often unaware of some of the work required to identify their desired modification in their cell lines. In this webinar, we discuss what you need to do for CRISPR genome editing after you have obtained your reagents from GeneCopoeia, the so-called Downstream work.

Watch recorded webinar / Download slides Title: GeneCopoeia CRISPR Genome Editing Technology Presented Wednesday, January 25, 2017

The ability to make specific changes at targeted genomic sites in complex organisms is fundamentally important to researchers in biology and medicine. Researchers have developed and refined chimeric DNA endonucleases, such as CRISPR-Cas9, to stimulate double strand breaks at defined genomic loci, allowing the ability to insert, delete, and replace genetic information at will. These tools can also be used without nucleases to induce or repress gene transcription. In this webinar, we discuss CRISPR and other genome editing technologies and the applications they make possible, and provide information on GeneCopoeia’s powerful suite of genome editing products and services.

Watch recorded webinar / Download slides Title: Applications For CRISPR-Cas9 Stable Cell Lines Presented Wednesday, March 22, 2017

The CRISPR-Cas9 system has become greatly popular for genome editing in recent years, due to its ease-of-design, efficiency, specificity, and relatively low cost. In mammalian cell culture systems, most genome editing is achieved using transient transfection or lentiviral transduction, which works well for routine, low-throughput applications. However, for other applications, it would be beneficial to have a system in which one component, namely the CRISPR-Cas9 nuclease, was stably integrated into the genome. In this webinar, we introduce GeneCopoeias suite of Cas9 stable cell lines, and discuss the great utility that these cell lines provide for genome editing applications.

Watch recorded webinar / Download slides Title: Safe Harbor Transgenesis in Human & Mouse Genome Editing Presented Wednesday, April 19, 2017

Insertion of transgenes in mammalian chromosomes is an important approach for biomedical research and targeted gene therapy. Traditional lentiviral-mediated transgenesis is effective and straightforward, but its random integration can often be unstable and harm cells. “Safe Harbor” sites in human and mouse chromosomes have been employed recently as an alternative to random, viral-mediated integration because they support consistent, stable expression, and are not known to hamper cell fitness or growth. In this webinar, we will discuss the merits of Safe harbor transgenesis approaches, and how GeneCopoeia’s CRISPR tools for Safe Harbor knock-in can greatly benefit your research.

Watch recorded webinar / Download slides Title: GeneCopoeia CRISPR sgRNA Libraries For Functional Genomics Presented Wednesday, April 29, 2015

Biomedical researchers are enjoying a Renaissance in functional genomics, which aims to use a wealth of DNA sequence informationmost notably, the complete sequence of the human genometo determine the natural roles of the genes encoded by the genome. As a result, biochemical networks and pathways will be better understood, with the hope of leading to improved disease treatments. Researchers are turning increasingly to CRISPR (clustered, regularly interspaced, short palindromic repeats) for functional genomics studies. Several groups recently adapted CRISPR for high-throughput knockout applications, by developing large-scale CRISPR sgRNA libraries. GeneCopoeia recently launched a number of smaller, pathway- and gene group-focused CRISPR sgRNA libraries, which offer several key advantages over the whole-genome libraries. In this 40 minute webinar, we discuss the merits and applications for CRISPR sgRNA libraries, how to use CRISPR sgRNA libraries, the advantages of using small, pathway- and gene group-focused libraries, and how GeneCopoeia can help you with your high-throughput CRISPR knockout studies.

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Answer:If you are doing simple gene knockouts in humans or mice, you can order CRISPR sgRNAs on our website. All you need to do is go to the , search for your gene, and then choose the appropriate clones that will work for your system. These CRISPR sgRNAs are designed by default to knock out all possible known and predicted transcript variants of your gene, and are targeted early in the coding regions. You can also order donor clones for these knockouts from the search results page. If you are doing a different application, such as introducing a point mutation, then you will need to and, after determining what you need, we will send you a custom quote.

Answer:For sgRNA clones (including both all-in-one Cas9/sgRNA clones and sgRNA-only clones, the default delivery format is bacterial stock. You have the option of ordering purified DNA for these clones for an additional charge. For HDR donor clones, the default delivery format is purified DNA.

Answer:The turnaround time for sgRNA clones (including both all-in-one Cas9/sgRNA clones and sgRNA-only clones) is 2-3 weeks. The turnaround time for HDR donor clones depends greatly on the nature of the modification that the clone is being used for. For HDR donor clones used for simple knockout, the turnaround time is 2-4 weeks. Other HDR donor clones, such as those used for fusion tagging or mutagenesis, can take 6-8 weeks, but can also take longer.

Answer:Yes. We sequence the inserts of each CRISPR sgRNA clone, and provide you with datasheets that show the full sequence of each clone (including HDR donor clones), a map, restriction enzyme digestions sites, and suggested sequencing primers. To obtain these datasheets, you just need to visit our on our website. You will need an account on our website, your catalog number(s), and your sales order number.

Answer:In the presence of drug, the only way for cells to survive is to integrate the plasmid into the chromosome, so it is possible to get drug-resistant clones that were only transfected with the donor plasmid. However, such integration is random. CRISPR increases donor targeting frequency by several orders of magnitude.

Answer:Our genome editing products can be used for virtually all species. Our standard plasmids for CRISPR are designed for work in mammalian cells. In addition, these plasmids can be used as templates for T7 promoter-driven in vitro transcription, for introduction into mice, zebrafish, Drosophila, and many other model organisms. Further, we can generate custom constructs that can be used in a wide variety of organisms.

Answer:Yes. The donor must be present when the DSB is formed in order to be used as a repair template. Otherwise, the cell must use non-homologous end joining (NHEJ) in order to repair the DSB, because unrepaired DSBs are lethal.

Answer:Our CRISPR plasmids typically do not integrate into the host genome in transfection experiments. However, after clonal selection for edited cells, we recommend screening clones for those which have lost the nuclease plasmids. This can be done by testing clones to see if they have become sensitive to the antibiotic of the resistance gene on the plasmid, or if they no longer express the plasmid’s fluorescent marker (where applicable). Our lentiviral clones are expected to integrate randomly into chromosomes.

1. If you are making an insertion or deletion, the easiest way to screen your cells is by PCR using primers flanking the modified site, provided that the insertion or deletion is large enough to detect by standard agarose gel electrophoresis.

2. For very small insertions or deletions, you can screen your clones using GeneCopoeia’s IndelCheck T7 endonuclease I assay, which is a method that detects mutations by cleaving double stranded DNA containing a mismatch. You can also screen using Sanger sequencing of PCR products.

3. If you are introducing a point mutation, then you can use either real-time PCR or Sanger sequencing to detect the modification.

4. If the modification you are introducing creates or destroys a restriction enzyme site, then enzyme cleavage of PCR products can be used to distinguish between modified and unmodified alleles.

5. Finally, either Sanger sequencing of PCR products or Next Generation sequencing of whole genomes can be used to screen for modifications. Regardless of which screening method you choose, it is also important that you are able to determine whether only a portion or all of the alleles have been modified.

In order to reduce the amount of time and effort required to identify edited clones, GeneCopoeia recommends our donor plasmid design and construction service. We will construct a donor plasmid that contains a defined modification, flanked by a selectable marker such as puromycin resistance, and homologous arms from your target region. The donor may or may not also include a fluorescent reporter such as GFP. The markers can be flanked by loxP sites, to permit Cre-mediated removal, if desired. Use of a GeneCopoeia-designed donor plasmid allows you to select for edited clones and reduces the number of clones required for screening. You can also purchase our donor cloning vectors for do-it-yourself donor clone construction.

Answer:Yes. Even though frameshifts are not possible with miRNAs and other noncoding RNAs, an indel occurring in a critical region, such as the mature sequence of a miRNA, should be enough to abolish its function.

Answer:The vector backbones of our CRISPR sgRNAs are designed to not replicate in the host. These plasmids, which are transiently transfected, will typically be lost after several rounds of cell division and will not further affect the host cell. After transfection, cells are plated at low density to promote the formation of single colonies. These colonies should be screened to ensure that they have lost the plasmid(s). This can be done by testing clones to see if they have become sensitive to the antibiotic of the resistance gene on the plasmid, or if they no longer express the plasmid’s fluorescent marker (where applicable). However, even if the TALEN or CRISPR plasmid integrates, it can no longer cut the site after it is edited, because NHEJ destroys the TALEN or sgRNA recognition site. To be completely assured that the transfection is transient, we recommend delivering RNA instead of plasmid DNA. If you are using HDR, we recommend engineering synonymous mutations into the donor to destroy the TALEN or sgRNA recognition site.

Answer:Yes. CRISPR has been shown to be able to disrupt multiple copies at once. The efficiency varies depending on different factors, such as cell type, transfection efficiency and TALEN/CRISPR activity.

Answer:Yes. We have the reagents for the Cas9 D10A nickase, and have successfully tested our double nickase designs. However, in order to create mutagenic DSBs, the nickase requires the correct targeting of two appropriately-spaced sgRNAs on opposite strands, flanking the break site. Because proper sgRNA targeting requires the presence of the N-G-G PAM site immediately following the recognition site, it might not always be possible to use the nickase for DSB formation. There are also high-fidelity variants of Cas9 nuclease that edit genes with greater specificity than wild type Cas9, but sometimes with reduced efficacy and with increased design constraints. However, since these high fidelity variants use only one sgRNA, they are easier to work with than Cas9 niclases.

Answer:Yes. To create a DSB, the nickase requires the correct targeting of two appropriately-spaced sgRNAs on opposite strands, flanking the break site. This is sufficient to stimulate HDR between the target site and the donor. While this method has the advantage of potentially fewer off-target NHEJ-mediated mutations, since single strand nicks are repaired with higher fidelity than DSBs, it is not without limitations. Proper sgRNA targeting requires the presence of the N-G-G PAM site immediately following the recognition site. Therefore, it might not always be possible to use the nickase for HDR.

Answer:We only sell plasmids containing our custom-designed CRISPR sgRNAs. If you need a negative control, we also sell a CRISPR plasmid containing a scrambled sgRNA.

Answer:Yes.

Answer:Yes. There is a double mutant of the Cas9 nuclease that completely abolishes nuclease activity. This mutant can be fused to a transcriptional modulator such as VP64 and targeted to specific genes. You can also use the catalytically dead Cas9 with properly-designed sgRNAs to repress, or interfere with, gene expression.

Answer:Yes. We have both non-viral and lentiviral formats. We also have , in which we can provide you with lentiviral particles expressing both Cas9 and sgRNAs.

Answer:Unfortunately, no. Lentiviruses enter cells as RNA, but HDR donors must enter the cells as DNA at the same time as Cas9 and the sgRNAs.

Answer:Lentiviral particles, transfection-ready DNA, and bacterial stock.

Answer:Yes. The lentiviral plasmids are “dual-use”, so that they can either be packaged into lentiviral particles or transfected into cells by standard transfection methods.

Answer:Our sgRNA representation does not need to be validated by Next Generation Sequencing. Each library is small compared with the genome-wide libraries, and each sgRNA clone is constructed individually, cultured in E. coli individually, then pooled as E. coli in approximately equal amounts. From those pools we prepare DNA and then, if necessary, lentiviral particles.

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GeneHero CRISPR Products and Services | Genecopoeia

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