Site Directed Mutagenesis (SDM) Monkey Deletion COS-7

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. Multiplexing such a reaction amplifies the design challenges where one target requires 3 primers, which should be exclusively bound nowhere in the template DNA or to each other. Similarly, two targets require 6, three require 9, and so on. Each amplicon needs to be either a different size (for gels) or labeled with a different fluorescent tag that is spectrally distinct from the others in the reaction. Further complicating this, different targets in the reaction can compete with each other for resources and causes more challenges in the detection of amplicons. However, with proper primer designing, their validation, optimize quality and concentration of the enzyme and buffers certainly lead to a successful multiplex PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. Multiplexing such a reaction amplifies the design challenges where one target requires 3 primers, which should be exclusively bound nowhere in the template DNA or to each other. Similarly, two targets require 6, three require 9, and so on. Each amplicon needs to be either a different size (for gels) or labeled with a different fluorescent tag that is spectrally distinct from the others in the reaction. Further complicating this, different targets in the reaction can compete with each other for resources and causes more challenges in the detection of amplicons. However, with proper primer designing, their validation, optimize quality and concentration of the enzyme and buffers certainly lead to a successful multiplex PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. A quantitative, real-time PCR reaction typically includes all of that plus a probe that can be detected fluorescently as the reaction runs, with no gel required. for detection. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. A quantitative, real-time PCR reaction typically includes all of that plus a probe that can be detected fluorescently as the reaction runs, with no gel required. for detection. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

Short hairpin or small hairpin RNA (shRNA) is artificial RNA, which has a hairpin loop structure, and uses inherent microRNA (miRNA) machinery to silence target gene expression. This is called RNA interference (RNAi). These can be delivered via plasmids or viral/bacterial vectors. Challenges in shRNA-mediated gene silencing include: 1. Off-target silencing, 2. Packaging shRNA encoding lentivirus, and 3. Stable transduction in cells. RNAi have been designed to have anywhere from 19-27 bs, but the most effective design has 19 bp. In case commercial shRNAs are not available, potential target sites can be chosen within exon, 5’- or 3’ UTR, depending on which splice variants of the gene are desired. One should use the latest algorithms and choose at least two different sequences, targeting different regions, in order to have confidence in overcoming off-target effects. A BLAST search after selecting potential design will eliminate potential off-target sequences. For the second challenge, sequencing the vector using primers for either strand (50-100 bp upstream) is suggested, along with using enzymatic digestion on agarose gel for the vector. Next, once the shRNA-containing vector is packaged in a virus, it is important to check the viral titer before transduction. Finally, using a marker in the lentiviral vector (fluorescent protein or antibiotic resistance), along with qPCR for target gene expression can help in determining efficacy of transduction and shRNA on its target site.

Short hairpin or small hairpin RNA (shRNA) is artificial RNA, which has a hairpin loop structure, and uses inherent microRNA (miRNA) machinery to silence target gene expression. This is called RNA interference (RNAi). These can be delivered via plasmids or viral/bacterial vectors. Challenges in shRNA-mediated gene silencing include: 1. Off-target silencing, 2. Packaging shRNA encoding lentivirus, and 3. Stable transduction in cells. RNAi have been designed to have anywhere from 19-27 bs, but the most effective design has 19 bp. In case commercial shRNAs are not available, potential target sites can be chosen within exon, 5’- or 3’ UTR, depending on which splice variants of the gene are desired. One should use the latest algorithms and choose at least two different sequences, targeting different regions, in order to have confidence in overcoming off-target effects. A BLAST search after selecting potential design will eliminate potential off-target sequences. For the second challenge, sequencing the vector using primers for either strand (50-100 bp upstream) is suggested, along with using enzymatic digestion on agarose gel for the vector. Next, once the shRNA-containing vector is packaged in a virus, it is important to check the viral titer before transduction. Finally, using a marker in the lentiviral vector (fluorescent protein or antibiotic resistance), along with qPCR for target gene expression can help in determining efficacy of transduction and shRNA on its target site.

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.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. A quantitative, real-time PCR reaction typically includes all of that plus a probe that can be detected fluorescently as the reaction runs, with no gel required. for detection. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. A quantitative, real-time PCR reaction typically includes all of that plus a probe that can be detected fluorescently as the reaction runs, with no gel required. for detection. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

Short hairpin or small hairpin RNA (shRNA) is artificial RNA, which has a hairpin loop structure, and uses inherent microRNA (miRNA) machinery to silence target gene expression. This is called RNA interference (RNAi). These can be delivered via plasmids or viral/bacterial vectors. Challenges in shRNA-mediated gene silencing include: 1. Off-target silencing, 2. Packaging shRNA encoding lentivirus, and 3. Stable transduction in cells. RNAi have been designed to have anywhere from 19-27 bs, but the most effective design has 19 bp. In case commercial shRNAs are not available, potential target sites can be chosen within exon, 5’- or 3’ UTR, depending on which splice variants of the gene are desired. One should use the latest algorithms and choose at least two different sequences, targeting different regions, in order to have confidence in overcoming off-target effects. A BLAST search after selecting potential design will eliminate potential off-target sequences. For the second challenge, sequencing the vector using primers for either strand (50-100 bp upstream) is suggested, along with using enzymatic digestion on agarose gel for the vector. Next, once the shRNA-containing vector is packaged in a virus, it is important to check the viral titer before transduction. Finally, using a marker in the lentiviral vector (fluorescent protein or antibiotic resistance), along with qPCR for target gene expression can help in determining efficacy of transduction and shRNA on its target site.