CRISPR Mouse Deletion 3T3-L1

ROS has a very short half-lives in biological environment as they are influenced by exposure to ambient oxygen. As it is highly reactive and hard to measure care should be taken to ensure the stability of the sample during isolation, preparation, storage, and analysis.

Protein isolation is a technique that involves isolation and/ or purification of protein from cells or tissues via chromatography or electrophoresis. The major challenges in protein isolation include: 1. The concentration of proteins in cells is variable and tends to be small for some intracellular proteins. Unlike nucleic acids, proteins cannot be amplified. 2. Proteins are more unstable than nucleic acids. They are easily denatured under suboptimal temperature, pH or salt concentrations. 3. Finally, no generalized technique/protocol can be applied for protein isolation. Proteins may have different electrostatic (number of positively or negatively charged amino acids) or hydrophobic properties. Therefore, protein purification requires multiple steps depending on their charge (a negatively charged resin/column for positively charged proteins and vice-versa), dissolution (using detergents) and unlike in the case of DNA and RNA, instead of using salts, proteins should be isolated by isoelectric precipitation.

An alternative to culture-based cell death detection is an assessment of other cell viability indicators using fluorescent dyes, including membrane potential and membrane integrity. Live/Dead assays differentiates live and dead cells using membrane integrity as a proxy for cell viability and are based on a fluorescent staining procedure followed by detection using flow cytometry. However, samples preparation for such flow cytometry-based techniques could be challenging. Cell harvesting by trypsinization, mechanical or enzymatic cell disaggregation from tissues, extensive centrifugation steps, may all lead to preferential loss of apoptotic cells. To overcome this strictly follow manufacturers instruction of the detection kit.

Cell cytotoxicity assays measure the ability of certain compounds or chemical mediators to reduce the viability of the cells. The term cell cytotoxicity assay can sometimes be used interchangeably with cell proliferation assay. Healthy living cells can be identified by the use of formazan dyes, protease biomarkers or by measuring ATP content. The formazan dyes are chromogenic products formed by the reduction of tetrazolium salts by dehydrogenases, such as lactate dehydrogenase (LDH) and reductases that are released during cell death. Common tetrazolium salts include INT, MTT, MTS and XTT. Cell cytotoxicity can also be measured by using the SRB and WST-1 assays. These assays can usually be used in a high-throughput fashion and can be quantitated by measuring absorbance, colorimetry or luminescence. All these assays require similar numbers of cell plating at the initiation, a time course of treatment with the cytotoxic agent and at least triplicates for each condition at every point of analysis. Cell shrinkage, plasma membrane blebbing, cell detachment, externalization of phosphatidylserine, nuclear condensation and ultimately DNA fragmentation are well-described features of apoptosis. The assays that rely on cell membrane integrity for their function, may not be able to quantify early apoptosis. Therefore, in order to distinguish early apoptotic vs. late apoptotic or necrotic cells, additional flow cytometry techniques can be used. A combination of Annexin V and PI (propidium iodide) can be used to distinguish early (Annexin V+/PI-) and late apoptotic (Annexin V+/PI+) cells. Sometimes, caspase assays are used in order to differentiate the stages of apoptosis.

Transfection is a powerful technique that enables the study of the function of genes and gene products in cells. Based on the nature of experiments, we may need a stable DNA transfection in cells for persistent gain-of-function or loss-of-function of the target gene. For stable transfection, integration of a DNA vector into the chromosome is crucial which requires selective screening and clonal isolation. By carefully selecting a viral delivery system and related reagents we can ensure safe and highly-efficient delivery of expression constructs for high-level constitutive or inducible expression in any mammalian cell type.

The RNA-guided CRISPR-Cas9 nuclease system has revolutionized the genome editing practices. For the most part, the Cas9-mediated genome editing is performed either via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in mammalian cells, However, designing of specific sgRNAs and minimizing off-target cleavage mediated mutagenesis are the major challenges in CRISPR-Cas based genome editing. To circumvent these issues, we can take advantages of many available tools and approaches for sgRNA construction and delivery.

The RNA-guided CRISPR-Cas9 nuclease system has revolutionized the genome editing practices. For the most part, the Cas9-mediated genome editing is performed either via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in mammalian cells, However, designing of specific sgRNAs and minimizing off-target cleavage mediated mutagenesis are the major challenges in CRISPR-Cas based genome editing. To circumvent these issues, we can take advantages of many available tools and approaches for sgRNA construction and delivery.

The RNA-guided CRISPR-Cas9 nuclease system has revolutionized the genome editing practices. For the most part, the Cas9-mediated genome editing is performed either via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in mammalian cells, However, designing of specific sgRNAs and minimizing off-target cleavage mediated mutagenesis are the major challenges in CRISPR-Cas based genome editing. To circumvent these issues, we can take advantages of many available tools and approaches for sgRNA construction and delivery.

The RNA-guided CRISPR-Cas9 nuclease system has revolutionized the genome editing practices. For the most part, the Cas9-mediated genome editing is performed either via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in mammalian cells, However, designing of specific sgRNAs and minimizing off-target cleavage mediated mutagenesis are the major challenges in CRISPR-Cas based genome editing. To circumvent these issues, we can take advantages of many available tools and approaches for sgRNA construction and delivery.

The RNA-guided CRISPR-Cas9 nuclease system has revolutionized the genome editing practices. For the most part, the Cas9-mediated genome editing is performed either via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in mammalian cells, However, designing of specific sgRNAs and minimizing off-target cleavage mediated mutagenesis are the major challenges in CRISPR-Cas based genome editing. To circumvent these issues, we can take advantages of many available tools and approaches for sgRNA construction and delivery.